Tag: Elements

  • Meaning, Definition, and Objectives of Career Management

    Meaning, Definition, and Objectives of Career Management

    Career Management; A common way of career action is by choosing a person to proceed through the life of his employment. It can represent as a person whom a person has organized for so many years. Career management is the engagement plan of someone’s activities and attachments in the work done during his life for better fulfillment, development and financial stability. This is a sequential process that starts with understanding itself and involves business awareness. Do you study to learn: If Yes? Then read the lot. Let’s Study Meaning, Definition, and Objectives of Career Management. Read this in the Hindi language: करियर प्रबंधन का अर्थ, परिभाषा, और उद्देश्य। 

    The concept of Career Management Discussing the topic: Meaning, Definition, Benefits, Objectives, and Elements of Career Development.

    Many people feel satisfied by achieving their career goals. Also, others have a strong sense that their career, their life, and their abilities have become incomplete. Employers’ employees also have a profound impact on their careers. Some organizations have formal career management procedures, while others worry very little about it. Career management is defined as the ongoing process of preparation, implementation, and monitoring of career plans. It can do either by a person alone or there may a consolidate activity with the organization’s career system.

    Meaning and Critical Concept of Career Management:

    Career management is a process that enables employees to better understand, develop and give direction to their career skills and to effectively utilize those skills and interests both within and outside the organization. Specialized career management activities provide realistic career-oriented assessment, post open jobs and offer formal career development activities.

    Career development involves the lifespan series of activities that contribute to a person’s career exploration, establishment, development, success, and fulfillment. Career planning is a deliberate process by which a person becomes aware of his skills, interests, motivation, knowledge and other such characteristics. He also receives and receives information about opportunities and options, identifies career goals and establishes action plans to achieve specific goals.

    Career management and career planning activities are complementary and can strengthen each other. Career management can also consider a lifelong, self-monitoring process of a career plan. It involves choosing and setting individual goals and preparing strategies for achieving them.

    The Concept of Career Management:

    However, in an organizational context, the focus is on taking action to meet the estimated human resources requirements.

    • A person’s career is the only source of natural expression of self. A school of thought describes the purpose of life and the work of someone’s manifestation and the purpose of existence or existence. Still, others believe that there is a big difference between a person’s career and his life. In any case, careers are an integral part of one’s life and hence its management is needed.
    • Career management is more or less like organizational management; There is no classification of individuals after all organizations! The process of career management starts with the construction of goals and objectives, which are short-lived or for short-term achievement.
    • This is a difficult task compared to a long-term career goal, which is more or far-sighted. Since the objective is short-term or immediate, it is verb-oriented. Second, it demands every moment, every moment of achievement. Then this step can be very difficult for those who are not aware of available opportunities or are not fully aware of their talents. However, more specific, measurable and achievable goals are likely to have more and more fruit plan management plans.
    • A well-prepared strategy is needed to achieve the goal, which means the action plan to achieve the goal. After this, it will have to draft or establish rules that govern procedures/policies/norms or rules or procedures.
    • The final step in the career management process is to evaluate the career management plan to ensure that progress is being made or if there is a need for some changes later.

    Benefits of Career Management:

    The following benefits below are;

    1] Staffing List:

    Effective Career Management ensures the continuous supply of professional, technical and managerial talent to meet an organizational goal.

    2] Staffing from within:

    Most organizations prefer to promote employees from within the available positions due to many potential benefits. To recruit from within, it requires a strong career management program, which ensures effective performance in the effective new job of employees.

    3] Resolving employees problems:

    Effective career management can act as a measure of some employees’ problems. Employee business rates can reduce due to the sense of the existence of opportunity within the organization. It may be easy to go for recruits because the company develops its employees and provides better career opportunities.

    4] The satisfactory employee needs:

    The present generation of employees is very different from those of the previous generation who are in the set of their needs. Then higher levels of education have raised expectations of their career and many employees are directly responsible for providing better opportunities to achieve their career expectations.

    5] Advanced Motivation:

    As progress with career path is directly related to job performance, one employee can motivate and can perform at the top level to meet career goals.

    6] Employment Equity:

    Effective Career Management Demands Try to eliminate fair and equitable recruitment, selection and appointment and discrimination against publicity and career mobility. Such positive programs have formal provisions which help in increasing the career mobility of women and other minority groups, which emphasize job equity.

    Objectives of Career Management:

    Career management programs include a large number of these human resource management practices with the following objectives:

    1] Assisting employees to improve their performance:

    Career management programs try to involve employees in setting their goals and identifying their strengths and weaknesses. It helps with the identification and convenience of the training needs and opportunities of the employees. This is achieving primarily by building the process of reaction and discussion in the performance management system of the institutions.

    2] Explain the available career options:

    Through career management programs, employees are informing about career options available within the institute. It helps the employees with the recognition of the skills and other qualities required for current and future jobs.

    Most Career Management programs want to focus on the employees’ career plans at the institute, thereby increasing their commitment to the organization. In doing so, career paths are developing which indicates the mobility in the various directions in the Institute for the employees.

    3] Align the aspirations of employees with organizational objectives:

    Many organizations strive to help employees in their career plans through career management programs. Career management programs now want to improve the job matching with the right staff. Evaluating the skills and competencies of the employees can help them adjust to those positions which make them better suited.

    Through the application of practices such as transfer and rotation, the operational effectiveness of an institution can improve. As a result of career management programs, the need for external recruitment can also reduce as the employees with the necessary abilities have come to know through their career planning activities.

    From the perspective of the employer, the objective of your Career Management program should be to ensure the availability of capable and skilled employees within your organization.

    Elements of Career Management:

    The following three elements are common to most career management programs:

    1] Career Planning:

    Career planning is a deliberate process to be aware of the opportunities, obstacles, options, and goals related to careers and the identification of programming work, education and related development experiences, to achieve specificity, direction, time and Sequence can provide.

    The goal of becoming something in life. Career planning is also a process done by employees and their supervisors. The employee is responsible for self-assessment, identifies career interests and needs for development. As part of the self-assessment process, the employee analyzes his skills and weaknesses, along with his strengths and weaknesses.

    Career planning is also more effective when done by an individual and organization jointly. There is a stake in the organization’s successful career plan. Because of the continuous supply of adequate training people are required to do jobs at every level of the organization.

    2] Career Path:

    Based on the career expectations identified in the career planning process, potential career paths are mapping to employees. Career path sets a sequence of posts for which employees can promote, moved and rotated. However, it should note that each employee may have a crowd of career pathing options.

    The career path should establish an organization’s career development system. The existence of such career paths communicates employees with specific step-by-step objectives and identifies the potential role model in the organization. In establishing a career path, employees and their supervisors should be realistic in terms of their ability and time limits. In which career goals can achieve in career paths.

    3] Career Development:

    Career Development refers to a planned effort to connect the person’s career needs with the workforce requirements of the organization. It can see as a process to help in organizing a career in musicians with business needs and strategic direction of the organization. It is also important to note that, with the concept of alignment between the person and the organization, career development is a continuous process. One of the roles of the organization is to provide training and development opportunities to meet the needs of the movement with the career path.

    While these three elements are identifying as different practices, they complement each other during the career management process and inform. Also, to choose any career path, you can use the services of different career evaluation tests at different stages. Which are in line with the likes and dislikes, strengths and weaknesses. These tests are from those people who are small and short, providing complete details of minutes. Some tests have multiple intelligence between MBTY (Myers and Briggs Type Indicator), SDI (Strength Deployment List) and others.

    The job of career management is more on the personal self than the employer. Ensuring personal development in terms of skills, competencies, changes in attitude over time, things may need to take care of someone. There is a need to complete and evaluate short-term goals. There is a need to revise long-term career goals with changes in employment scenario and self; Organizations cannot or may not worry on a large scale or combine your priorities with careers and lives. Often counseling is helpful to evaluate the job and prospects and to establish the clarity of values because they make changes with time. Read this in the Hindi language: करियर प्रबंधन का अर्थ, परिभाषा, और उद्देश्य। 

    Meaning Definition and Objectives of Career Management

  • A Good Advertisement Copy: Characteristics and Elements

    A Good Advertisement Copy: Characteristics and Elements

    Meaning: An “ad copy” is the medium through which an advertiser expresses his views as a message to readers. This article explains about A Good Advertisement Copy with discussion by Characteristics and Elements. It refers to all the reading cases of an advertisement, whether it is short or long, and includes the title, sub-title, text or body, an advertiser’s name or initials. An ad copy is sometimes known as “advertising message”. Also, learn A Good Advertisement Copy.

    Understand and Learn, A Good Advertisement Copy: Characteristics and Elements.

    Ad copy can be anything from a simple text to art form made of aesthetics or to a celebrity playing in the background or appearing in admirable music or ad in the background. A product or brand advertisement is done through many mediums. There are newspapers and magazines in which there are many pages of advertising.

    The advertisement in this form is known as the print media. Advertising can do through visual and audio media, which are usually television channels and radio channels. Regardless of how the advertisement is done, the jingles in the advertisements displayed or displayed in the words, serve as a continuous reminder for the brand and its products in our memory.

    An ad copy helps people targeted to an organization to communicate a specific message. Advertising copy plays an important role in taking marketing efforts for customers. Making an ad copy for print media and electronic media differs on different aspects. While print media ads have a positive effect on the position and appearance of the position, the electronic media is focused on catching people’s hearts within a few seconds of the allotted time.

    The Concept of the study Explains – A Good Advertisement Copy: Characteristics of a Good Advertisement Copy, and Elements of a Good Advertisement Copy.

    Characteristics of a Good Advertisement Copy:

    This article throws light on the few main characteristics of a good copy of the advertisement.

    The following characteristics are:

    • Attention Value.
    • Suggestive Value
    • Memorizing Value.
    • Conviction Value.
    • Sentimental Value.
    • Educational Value, and.
    • Instinctive Appeal Value.

    Now Explanation Each:

    Attention Value:

    The copy of an advertisement should so draft as to easily draw the attention of the prospects. This is the first requisite on which depends on the effectiveness of the ad­vertisement. Attraction can bring about by pictures, by the use of display types, borders, price quotations, reply coupons, etc. Which one or which of them will be most suitable depends on the individual condition of the product and the market.

    Suggestive Value:

    The suggestion as to the use and quality of the product makes a copy of the advertisement a good one. The re­peated use of a suggestion, a command or a slogan can do the trick. Coca-Cola, Pepsi are examples.

    Memorizing Value:

    The copy of the advertisement should so draft as to make it suitable to stick to the memory of the in­dividual reader. Repetition of the advertisement is an effective way of creating memorizing value. In any copy of advertise­ment of a branded product, the advertiser must stress the brand name repeatedly. (Vim, Coca-Cola, etc.).

    Conviction Value:

    Convincing arguments add value to a copy of the advertisement. To create the conviction value, the advertiser will have to avoid both extremes it should neither be a plain notice to the prospects announcing the availability of a certain product nor should it use flowery and high-flown language to advertise a product, without giving any tangible and appealing reasons why the customer should prefer the product to the rival products in the market.

    Sentimental Value:

    Sentiments play a very important role in any matter. In advertising, it must not overlook that the sentiments of those for whom the advertisement is primarily meant rouse or at least not injured or adversely affected.

    Educational Value:

    A copy of the advertisement, though is commercial, we must not forget that the advertise­ment should contain information that has some educational value. An advertisement not only retains an existing market but creates the market for the future. The copy of the advertisement should be informative and must contain in it the ingredients that will help people to change their habits in such as to be conducive to create additional demand.

    Instinctive Appeal Value:

    Certain instincts are ingrained in human beings. The copy of the advertisement should so draft as to encourage those instincts that are relevant for the product advertised. Advertising is essentially the motivation of the po­tential consumer and to activate the motivation, an appeal is of very great significance.

    Generally speaking, a good of advertis­ing should direct to:

    1. Self-preservation instinct,
    2. Hoarding instinct,
    3. The instinct for self-display,
    4. Parental in­stinct and,
    5. Something for nothing instinct (vague desire’ to get something without paying for it).

    Based on these basic instinctive appeals, the follow­ing themes may lay down for a copy of good advertisement: pride, beauty, health, economy, comfort, fear, parental affec­tion, patriotism, achievement, emulation, and imitation.

    The Elements of a Good Advertising Copy:

    The make-up or parts of the copy of the good advertisement or advertising can view from two aspects – elements below are:

    1. Advertising theme, and.
    2. Advertising layout.

    Now, explain each one;

    Advertising Theme:

    A theme represents a particular viewpoint or a central idea with which the message is conveyed to the consuming public. The theme involves a rational appeal based on human emotions, desires or sentiments. Such well-thought-out and specific appeals became effective in arousing desire and in initiating action on the part of consumers.

    Elements of Good Advertisement Copy – The following are the common themes used in advertising:

    The theme of beauty:

    The sales appeal for cosmetics, perfumeries, and toilet products are usually based upon the theme of beauty. Accordingly, the message of the advertisement contains expressions like “For romantic or charming appearance, use product A”, “Product B ensures alluring or exquisite complexion”, or “Care your hair with product C for the glossy glimpse and luxuriant growth.”

    The theme of pride:

    The sales message in the case of pieces of jewelry, radios, costly clothes, motor cars, and others is laid upon the theme of pride since the acquisition of such products deems as proud possessions on the part of buyers. For example, “Prestige car means A”, “Radio B adds decency to any home”, “Discerning people prefer fabric C”, or “X’s Jewellery adorns fashionable ladies.”

    The theme of health:

    Food products and drugs are advertising through reliance upon the theme of health. To take some examples, “Product A supplies boundless energy and vigor”, “Health brings happiness—and the key to health help by product B”, “Product C keeps you free from disease”, or “Eminent physicians prescribe D for cold and cough.”

    The theme of comfort:

    Products which aid in giving comfort to the people at work or home are advertising through the theme of comfort. Elec­trical fans, air-conditioning plants, refrigerators, and the likes belong to the group of products meant for providing comfort.

    The theme of the economy:

    This is a common appeal use in many cases for making bargaining purchase, for saving money or for protecting costly things from decay and destruction.

    The theme of fear:

    The theme of fear utilizes by insurance companies and safety-vault operators in expanding the demand for their services. Possible dangers and their consequences are presenting in the copy of advertising for initiating action on the part of their customers.

    The theme of emulation:

    The desire for imitation strongly implants in human nature. By giving illustrations and factual information as to what some distinguished persons do, the message of the advertisement may call for imitation on the part of others. To take one case, “The succ­essful men all over the globe use Blade A.”

    The theme of distinction:

    The desire for individual recognition, distinct social status, and superior community standing is inherent in human beings. As an outward mark of that distinction, selected products of very expensive nature are acquiring by a class of people who may be high-borns or aristocrats.

    The theme of affection:

    Baby foods, toys, and other playthings are advertising based on this theme. By directing appeal towards parental love, the copy of advertising becomes effective in securing action on the part of buyers.

    The theme of patriotism:

    The appeal for products of national origin is sometimes based upon national sentiments. For the prosperity of a nation and its citizens, the theme of patriotism makes out a case for using national products in preference to goods of foreign origin.

    Advertising Layout:

    The layout is the logical arrangement of compo­nents of an advertisement in the copy and deals with the systematic presentation of the message. The pattern of layout varies according to the medium to use.

    For newspapers and magazines, the presentation of the message is visible in written words and pictures; in radio, the presentation is audible in spoken words and sound effects; and in television, both audio and visual presentations are practicable. In all cases, balance and symmetry are of prime importance in presenting the message within the allotted space or time.

    Visual layout in any publication can divide into the following three parts:

    Headlines:

    Headlines are using in bold letters for drawing atten­tion of the consuming public. The size and length of the headline must be appropriate to the general format and page size of the publication; it must also be in keeping with the theme of advertising and with the entire makeup of the copy.

    Usually, short headlines are giving stressing some facts, suggestions, prepositions or convictions. In magazines and trade journals, color printing adopts for headlines to make than more promi­nent and conspicuous.

    Illustrations:

    Illustrations are giving by way of pictures, symbols or photographs for drawing attention, creating interest as well as for arousing desire. Significant illustrations may be worth a thousand words in securing public reception for the product.

    But limits of decency must not exceed in presenting pictures or photographs which should always be in good taste. Obscene and objectionable pictures do more harm than good to the cause of advertisement.

    Texts:

    Texts provide the heart of the message of advertisements, and they are to weave around an advertising theme. For an individual copy, one theme is desirable; a multiplicity of themes creates confusion and weakens the strength of appeal. For presenting the text, different practices are following in the business world.

    In some cases, the text prefaces by a statement of the problem to the reader and follow by a solution thereof. In other cases, reading materials are presenting analytically with pertinent facts and data. Furthermore, the text may present by the use of a typeface in one copy or of hard lettering in another copy.

    A Good Advertisement Copy Characteristics and Elements - ilearnlot
    A Good Advertisement Copy: Characteristics and Elements #Pixabay,

  • Explain essay on the Direction of an Organization!

    Learn, Explain essay on the Direction of an Organization!

    Before start studying, you must know what common question types asked around the place. Essay for Articles: What is the Essay on the Meaning of Direction? What is the Essay on the definition of Direction? What is the Essay on the Elements of Direction? What is the Essay on the Importance of Direction? What is the Essay on Written VS Oral Directives? What is the Essay on the Techniques of Direction? and What is the Essay on the Principles of Direction? Also learned, The Importance of Directing in an Organization! Explain essay on the Direction of an Organization!

    Now Explain it:

    #The Essay on Meaning of Direction:

    Direction involves communication and providing leadership to the subordinates and motivating them to contribute to the best of their capability for the achievement of organizational objectives. It is concerned with influencing the behavior of human resources for the accomplishment of organizational objectives.

    Directing concerns the total manner in which a manager influences the actions of his subordinates. It is the final act of a manager getting others to act after all preparations have been completed. It starts with issuing orders and instructions to the subordinates and ends with getting the work done. Related question – Explain Principles for Achieving Effective Direction in Management!

    #The Essay on the Definition of Direction:

    In the words of Ernest Dale, “Direction is telling people what to do and seeing that they do it to the best of their ability. It includes making assignments. Corresponding procedures, seeing that mistakes are corrected, providing on-the-job instructions and, of course, issuing orders.”

    According to Theo Haimann, “Directing consists of the processes and techniques utilized in issuing instructions and making certain that operations are carried out as originally planned.”

    According to Koontz and O’Donnell, “Directing is the interpersonal aspect of managing by which subordinates are led to understand and contribute effectively and efficiently to the attainment of enterprise objectives.”

    #The Essay on Elements of Direction:

    These are four elements of direction discussed below:

    #Supervision:

    It is the process by which conformity between planned and actual results is maintained. Effective supervision ensures greater output of high quality. It reaches the subordinates the way their tasks are to be performed.

    #Leadership:

    It is the process by which a manager guides and influences the work of others in choosing and attaining specified goals. According to Chester Barnard, “Leadership is the quality of the behavior of the individuals whereby they guide people and their activities in the organized effort.”

    #Communication:

    A manager has to tell the workers what they are required to do how to do and when to do it. He has to create an understanding in the minds of the subordinates of the work to be done. This is done by the process of communication.

    #Motivation:

    Motivation is the function of a manager to motivate the people working under him to perform the work assigned. A successful manager has made proper use of motivation to enthuse the people to work harmoniously for the attainment of desired objectives.

    #The Essay on Importance of Direction:

    These are some of the importance of direction discussed below:

    The direction is the function of management which follows planning, organizing, and staffing. Once objectives have been formulated and plans have been drawn, it is necessary to implement the plans. This can be accomplished by directing the people and their activities.

    It is through directing that managers get the work done through people. The direction is the process of guiding, supervising, leading and motivating the subordinates to work in a way that is beneficial to the enterprise. The manager not only shows the right path but also leads the subordinates to achieve the objectives of the enterprise. He creates a sense of belongingness, faith, and loyalty among the subordinates.

    The importance of direction in an organization can be viewed by the fact that every action is initiated through direction. Since, human, beings in the organization handle the physical resources that are men, money, material, machinery, etc. to accomplish certain functions by which organizational objectives are to be achieved. This necessitates the importance of the direction function as an important factor for achieving organizational efficiency and effectiveness.

    In this context, the importance of direction is discussed as follows.

    #Direction Initiates Action:

    Through direction, management conveys and motivates individuals in the organization to function in the desired way in order to achieve organizational objectives. Without direction, other managerial activities like planning, organizing, and staffing become ineffective.

    #Direction Integrates Group Efforts:

    Management uses various techniques of direction to integrate the efforts of different individuals in the organization. Since their actions are inter-related in such a way that each individual’s performance affects the performance of others in the organization. Direction integrates the activities of the employees by supervision, guidance, and counseling.

    #Direction Facilitates Changes:

    As we all know, organizations exist as a part of the ever-changing environment, the dynamic nature of environment often require changes in the business enterprise. Direction helps the management to incorporate and implement these changes through better communication and leadership.

    #Direction Improves Efficiency through Motivation:

    Direction deals with an essential and sensitive factor of production that is the human factor. Every individual in the organization has a potential which can be utilized optimally only through motivation, leadership and effective communication which are essential elements of direction.

    #Direction Provides Stability and Balance in the Organization:

    Effective leadership, communication, and motivation provide stability and maintain balance in individual and organizational interest. The organization with the help of direction expands and grows in the right direction in order to achieve a stable existence.

    “Direction Helps Initiating Action and Integration”:

    The human resources available to management in an organization must be properly activated. It is through the combined efforts of people that various resources are utilized for the achievement of organizational objectives. Therefore, the direction of human efforts is a central responsibility of management everywhere.

    The effectiveness with which human resources are led, motivated and utilized determines the success in achieving organizational objectives. The need for direction arises to deal effectively and efficiently with the human factor for the accomplishment of goals of the enterprise.

    People working in the enterprise have to be told what they should do and they have also to be guided and induced to accomplish this. Moreover, individuals have their own goals which they expect to fulfill through the enterprise. These goals may be entirely different from those of the enterprise.

    The effective direction is a must to achieve congruency in the goals of the enterprise and those of the individuals. It will lead to replacing the existing behavior patterns of the individuals by those which are in conformity with the requirements of the organization.

    #The Essay on Written VS Oral Directives:

    The directives may be either written or oral.

    Some of the advantages of written directives are as follows:

    • Written orders are comparatively more intelligible and the chances for misunderstanding and duplication of effort will be minimized.
    • Written orders lead to clarity of thought and the quality of directive is, thus improved considerably.
    • A written order can be consulted readily to maintain accuracy.
    • The subordinate also gets an ample opportunity to study directive carefully.
    • The written order also makes it possible to communicate it to all interested parties simultaneously.
    • In case of written orders, every member of the organization is certain of his job. This improves the accountability aspect of management.

    In spite of numerous advantages, written directives suffer from the following disadvantages:

    • Written instructions are expensive and more time-consuming.
    • Written instructions might lead to an undesirable degree of inflexibility. Revision of written instructions is difficult. But it is not so difficult to revise an oral order.

    According to Theo Haimann, “Oral orders are almost invariably used when the action required is relatively simple in character. Also in times of emergency oral orders are almost always used. In order to strike a happy medium between the advantages and disadvantages of a written instruction, it is often expedient to put merely the important points of the instruction in writing and to give additional information orally.”

    #The Essay on Techniques of Direction:

    The main techniques of direction are given below:

    • Consultative Direction.
    • Free Rein Direction, and.
    • Autocratic Direction.

    Now Explain it:

    #Consultative Direction:

    Under this technique of direction, the executive consults with his subordinate concerning the feasibility, the workability, and the extent and the content of a problem before the superior makes a decision and issues a directive. It does not weaken the manager’s formal authority because the right to decide still remains with him. Here participation can occur at every level of organization.

    To make this technique a success, it is essential that the subordinate must be in favor of it. If the subordinate is the kind of a person who believes that the boss knows best and that making decisions and giving directives is none of his concern then there is a little likelihood that the opportunity to participate induces better motivation and better morale.

    One of the clear disadvantages of this technique is that the directive emerging from this consultation does not appear to the subordinate as an order, but as a solution which came directly from him or in which he participated. This assures the subordinate’s best cooperation and enthusiasm in carrying it out.

    Some other disadvantages of this technique are as follows:

    (i) There is a danger that the executive, in his desire to consult with his subordinates, might give them the impression of being not able to come to a decision.

    (ii) At times the subordinates consider it their right and prerogative to be consulted before a directive is given to them by their superior.

    #Free Rein Direction:

    This technique of direction encourages and enables the subordinate to contribute his own initiative, independent thought, drive perspicacity and ingenuity to the solution of the problem. This does not mean no- rein technique. He assigns the task not in a specific way but in general terms.

    In this technique, the initiative remains with the subordinate. The subordinate will have to select the solution and carry it out. This technique of direction will probably show the best and quickest results if the subordinate is the brilliant young man, highly educated, who has a sincere desire to become a top-level manager.

    #Autocratic Technique:

    The antithesis of free rein technique is the autocratic method where the executive substitutes command for the more informal methods and hands down detailed and precise orders in connection with the close supervision of subordinates.

    When the autocratic technique is adopted, the manager gives direct, clear and precise orders to his subordinates with detailed instructions as to how and what is to be done. The most democratic manager will find himself forced into issuing autocratic commands.

    #The Essay on Principles of Direction:

    The basic principles of direction are discussed below:

    • Harmony of Objectives.
    • Unity of Command.
    • Direct Supervision.
    • Effective Communication, and.
    • Effective Leadership.

    These are explained in brief as follows:

    #Harmony of Objectives:

    Every individual is assigned a particular job and he himself is responsible to complete that. He can do it in a better way only when he thinks that it is going to attain his personal objectives which may be different from the organizational objectives. So, the manager must try to reconcile the personal objectives of his subordinates with those of organizational objectives.

    #Unity of Command:

    This principle of direction states that a subordinate should get orders and instruction from one boss. He is responsible to one boss only. It is the best principle if it is not affected by the dual command.

    #Direct Supervision:

    Supervision refers to the direct and immediate guidance and control of subordinates in the performance of their task. Direct supervision by the boss and his direct advice to the subordinates boosts their morale resulting into renewed and vigorous effort. It also increases loyalty among the subordinates which is better for effective direction.

    #Effective Communication:

    Effective communication fosters mutual understanding, secures greater efforts from the subordinates and helps in co­ordinating the activities of an organization. Effective communication is an instrument of direction.

    Communication is complete only when the receiver receives and accepts the message intended. Two-way communications give the subordinates a chance to express their feelings and the boss to know the feelings of the subordinates. Misunderstanding, if any, can be removed through effective communication. Participation of subordinates in decision-making and responsibility is essential to make communication really effective and meaningful.

    #Effective Leadership:

    The success of an organization depends upon the quality of leadership exhibited by its managers at every level. Subordinates are happy if they get effective leadership from their boss. The boss must possess the qualities of a good leader if he is to get the work done with and through subordinates.

    The style of leadership adopted by a manager may be directive or democratic depending upon the needs of the situation, In any case, the manager cannot afford to overlook the interests of the subordinates. A person can exercise leadership over his subordinates only when he can fulfill their aspirations, and when they are satisfied with the type of leadership provided.

  • The Importance of Directing, with Aspects or Elements!

    Explain the Importance of Directing, with Aspects or Elements!

    The main Aspects or Elements of directing are as follows: Issuing Orders and Instructions, Leadership, Communication, Motivation, Supervision, and Co-ordination.  Importance of Directing are following: Initiates Action, Improves Efficiency, Ensures Co-ordination, Helpful in Implementing Changes, Provides Stability, Motivation, Supervision, and Co-ordination. Define of directing: “The heart of administration is the directing function which involves determining the course, giving order and instructions, providing the dynamic leadership.” Also learn, Production Management,  Now learned The Importance of Directing, with Aspects or Elements!

    Marshall E. Dimock “Directing consists of the process and techniques utilizing in issuing instructions and making certain that operations are carried out as originally planned.”

    Haimann remarks from the above definitions, we can conclude that the directing function of management is the heart of management process as it is concerned with initiating action. It consists of all those activities which are concerned with influencing, guiding or supervising the subordinates in their job.

    Aspects or Elements of Directing or Direction:

    Directing is a very important function of management. It is rightly called the heart of management process as it is concerned with initiating action. It consists of all those activities which are concerned with influencing, guiding or supervising the subordinates in their job. Related questions: What is the Importance of Directing Functions?

    The main aspects or elements of direction are as follows:

    • Issuing Orders and Instructions.
    • Leadership.
    • Communication.
    • Motivation.
    • Supervision, and
    • Co-ordination.

    Now Explain:

    1. Issuing Orders and Instructions:

    A manager is required to issue a number of orders to his subordinates to initiate, modify or halt any action. He is also required to guide and instruct workers in performance of their task towards the achievement of desired goals. Instructions are important in directing subordinates. Orders and instructions reflect the decisions of managers.

    A good order or instruction should have the following characteristics:

    • It should be simple, unambiguous and clear.
    • It should be brief but complete.
    • It should be reasonable and enforceable.
    • It should be convincing and acceptable.
    • It should invoke co-operation.
    • It should be compatible with the objectives of the organization.
    • It should “be in written form as far as possible.
    • It should be backed up by follow-up action.

    2. Leadership:

    Leadership is “the process by which an executive or manager imaginatively directs/guides and influences the work of others in choosing and attaining specified goals by mediating between the individual and organization in such a manner that both will get maximum satisfaction.” It is the ability to build up confidence and zeal among people and to create an urge in them to be led. To be a successful leader a manager must process the qualities of foresight, drive, initiative, self-confidence, and personal integrity. Different situations may demand different types of leadership viz., autocratic leadership, democratic leadership and free-rein leadership.

    3. Communication:

    Communication constitutes a very important element of directing. It is said to be the number one problem of management today. Communication is the means by which the behavior of the subordinates is modified and change is effected in their action.

    The word communication has been derived from the Latin word ‘Communis’ which means ‘common’. Thus, communi­cation means sharing of ideas in common. The essence of communication is getting the receiver and the sender tuned together for a particular message. Communication refers to the exchange of ideas, feelings, emotions, knowledge, and information between two or more persons.

    In management ideas, objectives, orders, appeals, observations, instructions, suggestions etc. have to be exchanged among the managerial personnel and their subordinates operating at different levels of the organization for the purpose of planning and executing the business policies. Directing will mainly depend upon the effectiveness of communication. In case the orders and instructions are not properly conveyed then these may not be properly implemented.

    4. Motivation:

    It is an important element of directing function. Motivation encourages persons to give their best performance and help in reaching enterprise goals. It is the degree of readiness for undertaking the assigned task and doing it in the best possible way. The directing function tries to make the best use of various factors of production available in the organization. This can be achieved only when employees co­operate in this task. Efforts should be made to make employees contribute their maximum.

    5. Supervision:

    It consists of the process and technique involved in issuing instructions and confirming that operations are carried as originally planned. Supervision is a continuing activity and performed at every level of activity. It is inevitable at every level of management for putting the managerial plans and policies into action. In a way, supervision is a sort of control as the supervisor is supposed to take corrective measures if the work is not in line with the plan.

    6. Co-ordination:

    Co-ordination is an orderly arrangement of the group effort to provide unity of action in pursuit of common purpose. The purpose of directing is to get various activities coordinated for achieving common goals. Co-ordination involves the integration of various parts of the organization. In order to achieve goals of an enterprise, both physical as well as mental co-ordination should be secured. Co-ordination is a part of directing exercise and helps in synchronization of various efforts.

    The Importance of Directing or Direction:

    Directing various employees in an organization is an important managerial task. It is indispensable for achieving enterprise objectives.

    Effective direction provides the following advantages:

    • Initiates Action,
    • Improves Efficiency,
    • Ensures Co-ordination,
    • Helpful in Implementing Changes,
    • Provides Stability,
    • Motivation,
    • Supervision, and.
    • Co-ordination.

    Now Explain:

    1. Initiates Action:

    The direction is required to initiate action. The functions of planning, organizing, staffing etc., will be taken up only when the direction is given to initiate them. Direction starts the actual work for achieving enterprise objectives.

    2. Improves Efficiency:

    A manager tries to get maximum work from his subordinates. This will be possible only through motivation and leadership and these techniques are a part of direction.

    3. Ensures Co-ordination:

    Direction helps in ensuring mutual understanding and teamwork. The individual efforts are directed in such a way that personal performances help in achieving enterprise objectives. The integration of various activities is possible through direction.

    4. Helpful in Implementing Changes:

    A business operates in a changing environment. New situations develop every now and then. A proper system of motivation will help employees in taking up new challenges.

    5. Provides Stability:

    Effective leadership, supervision and motivation will help in the smooth growth of an enterprise. A growing concern will provide stability to its activities.

    6. Motivation:

    Motivation is an important element of direction. Motivation is a factor which encourages persons to give their best performance and help in achieving enterprise goals. A strong positive motivation will enable the increased output of employees. A key element in direction is motivation. It helps in getting willing co-operation of employees. Every organization makes efforts that its employees contribute maximum to achieving enterprise goals.

    7. Supervision:

    Direction involves giving instructions to employees for undertaking some work. In order to see whether employees are doing the things as per targets or not there is a need for supervision. In supervision, all the activities of the employees are controlled and efforts are made to ensure proper achievement of targets. In case the performance is less than the targets then remedial steps are taken for improving the performance. So supervision is an integral part of direction.

    8. Co-ordination:

    Direction will be effective only when there is a proper co-ordination. In direction, different persons are asked to perform specific tasks. In order to see that efforts of every employee are in the direction of achieving organizational goals, there is a need to coordinate various activities. In the absence of coordination, every person will go in his own direction without bothering for the enterprise target. When various activities are co-originated then overall enterprise objectives will be easily achieved.

  • Explain are Evolution, Elements of an Organizational Climate!

    Explain are Evolution, Elements of an Organizational Climate!

    First, learn Evolution, after Elements of an Organizational Climate: Classical organization theory dominated management thinking during the first half of the twentieth century. Its organization can trace back to the ideas of Adam Smith who is the wealth of nations showed, as early as 1776, how the division of labor could improve the productivity of pin markers a hundredfold or more. However, it was only in the early 1900s that men like Fredrick, W. Taylor, Henry Fayol and Max Weber developed the full philosophy of the classical theory.

    Learn and Understanding, Evolution, Elements of an Organizational Climate!

    The classical approach to organization design was based on;

    (a) The full decision of labor, (b) Rigid hierarchy, and (c) Standardization of labor to reach its objectives. The idea was to lower costs by using unskilled repetitive labor that could train easily to do a small part of a job.

    The said approach did result in a substantial increase in economic productivity. As it turned out, however, these gains often involved considerable human cost. Because of an excessive division of labor and over-dependence on rules, procedure, and hierarchy, the workers became isolated from his fellow workers and felt alienated. The result was higher turnover, absenteeism, and decline in the quality of products.

    It took the academicians and practitioners of management some time to recognize the nature and severity of the problem. Roethlisberger and Dickson offered a behavioral interpretation of management based on their findings from the famous Hawthorne studies. They stressed the importance of individual differences, informal group interactions, and participation in decision – making.

    The sum total of these and many other such activities creates an internal an environment within each organization, which accounts for its uniqueness and identify members of an organization who work within and continuously influenced by this the internal environment which is also called organizational culture or organizational climate. Each organization deals with its members in a variety of ways in the course of their employment to obtain their co-operation in achieving organizational objectives.

    The management of an organization must satisfy various needs of the employees, through activities such as allocation of resources, rewards and punishment, the pattern of communication, mode of decision making, style of leadership, and so on. An organization influences the feelings, attitudes, and behaviors of its members.

    The Following Elements of an Organizational Climate are!

    The organizational climate is the general set of attitudes that the members of an organization, especially its management, have. These attitudes can affect decision-making and member satisfaction with the organization. Organizational climate concepts apply to businesses, nonprofit organizations, clubs and any other situation where groups of people gather for a common purpose.

    Diversity

    Each organizational climate has its own attitude towards diversity, either positive, negative or somewhere between. Ideally, all organizational climates should have a positive attitude toward diversity. Organizations should not discriminate against people based on race, religion or gender.

    Centralized or Decentralized

    Organizational climates are either centralize and hierarchical or decentralize, Centralize organizations give certain individuals power over others. Decentralize organizational cultures have authority spread out among different members.

    As workers become more specialized, they need more autonomy and self-regulation. Since authority figures will not always have the knowledge necessary to manage more sophisticated tasks. However, workers have more responsibilities placed on them in decentralized organizations than in centralized organizations, since they mainly decide which actions they will take, not the superiors.

    Formal or Informal

    The climate can have a more formal or informal structure. Formalized structures have standardized rules about how workers carry out activities in the organization, While less formalized structures give members the freedom to engage in alternative solutions to problems, with members having more freedom.

    Social Interaction

    The level of social interaction in organizational climate influences. How innovative and cooperative the climate is, according to Chung-Jen Chen and Jing-Wen Huang in the International Journal of Information Management. Some organizational climates are more teamwork-oriented, While other organizational climates have isolated members operating on their own. Teamwork-oriented climates are more supportive.

    Integration

    Integration is the extent of where the subdivisions of the organization work together. Organizations that are highly integrated have more opportunities for the members to work together. Share information, learn from each other, solve problems and identify potential problems that other members miss.

    Self-Direction

    Organizations vary in the extent to which the members feel like they have control over themselves and the organization. Some organizational climates have a high degree of stress, which increases the chances that members will experience burnout and increases the rate at which members leave due to low satisfaction with the organization. Workers experience burnout when they feel exhausted both emotionally and with their work.

    Explain are Evolution Elements of an Organizational Climate - ilearnlot
    Explain are Evolution, Elements of an Organizational Climate!

    Reference

    1. Evolution of OC,
    2. Following Elements of OC, and
    3. Photo Credit URL.

  • Cellular Respiration

    What is Cellular Respiration?

    Some organisms, such as plants, can trap the energy in sunlight through photosynthesis (see Photosynthesis) and store it in the chemical bonds of carbohydrate molecules. The principal carbohydrate formed through photosynthesis is glucose. Other types of organisms, such as animals, fungi, many protozoa, and a large portion of bacteria, are unable to perform this process. Therefore, these organisms must rely on the carbohydrates formed in plants to obtain the energy necessary for their metabolic processes.

    Animals and other organisms obtain the energy available in carbohydrates through the process of cellular respiration. Cells take the carbohydrates into their cytoplasm, and through a complex series of metabolic processes, they break down the carbohydrates and release the energy. The energy is generally not needed immediately; rather, it is used to combine adenosine diphosphate (ADP) with phosphate ions to form adenosine triphosphate (ATP) molecules. The ATP can then be used for processes in the cells that require energy, much as a battery powers a mechanical device.

    During the process of cellular respiration, carbon dioxide is given off. This carbon dioxide can be used by plant cells during photosynthesis to form new carbohydrates. Also in the process of cellular respiration, oxygen gas is required to serve as an acceptor of electrons. This oxygen is identical to the oxygen gas given off during photosynthesis. Thus, there is an interrelationship between the processes of photosynthesis and cellular respiration, namely the entrapment of energy available in sunlight and the provision of the energy for cellular processes in the form of ATP.

    The overall mechanism of cellular respiration involves four processes: glycolysis, in which glucose molecules are broken down to form pyruvic acid molecules; the Krebs cycle, in which pyruvic acid is further broken down and the energy in its molecule is used to form high-energy compounds, such as nicotinamide adenine dinucleotide (NADH); the electron transport system, in which electrons are transported along a series of coenzymes and cytochromes and the energy in the electrons is released; and chemiosmosis, in which the energy given off by electrons pumps protons across a membrane and provides the energy for ATP synthesis. The general chemical equation for cellular respiration is:

    C6H12O6 + 6 O2 → 6 H2O + 6CO2 + energy

    Figure 1. provides an overview of cellular respiration. Glucose is converted to pyruvic acid in the cytoplasm, which is then used to produce acetyl CoA in the mitochondrion. Finally, the Krebs cycle proceeds in the mitochondrion. Electron transport and chemiosmosis result in energy release; ATP synthesis also occurs in the mitochondrion.

    Glycolysis

    Glycolysis is the process in which one glucose molecule is broken down to form two molecules of pyruvic acid (also called pyruvate). The glycolysis process is a multi-step metabolic pathway that occurs in the cytoplasm of animal cells, plant cells, and the cells of microorganisms. At least six enzymes operate in the metabolic pathway.

    In the first and third steps of the pathway, ATP energizes the molecules. Thus, two ATP molecules must be expended in the process. Further along in the process, the six-carbon glucose molecule converts into intermediary compounds and is then split into two three-carbon compounds. The latter undergo additional conversions and eventually form pyruvic acid at the conclusion of the process.

    During the latter stages of glycolysis, four ATP molecules are synthesized using the energy given off during the chemical reactions. Thus, four ATP molecules are synthesized and two ATP molecules are used during glycolysis, for a net gain of two ATP molecules.

    An overview of cellular respiration

    Figure 1. An overview of cellular respiration.

    Another reaction during glycolysis yields enough energy to convert NAD to NADH (plus a hydrogen ion). The reduced coenzyme (NADH) will later be used in the electron transport system, and its energy will be released. During glycolysis, two NADH molecules are produced.

    Because glycolysis does not require oxygen, the process is considered to be anaerobic. For certain anaerobic organisms, such as some bacteria and fermentation yeasts, glycolysis is the sole source of energy.

    Glycolysis is a somewhat inefficient process because much of the cellular energy remains in the two molecules of pyruvic acid that are created. Interestingly, this process is somewhat similar to a reversal of photosynthesis (see Photosynthesis).

    Krebs Cycle

    Following glycolysis, the mechanism of cellular respiration involves another multi-step process—the Krebs cycle, which is also called the citric acid cycle or the tricarboxylic acid cycle. The Krebs cycle uses the two molecules of pyruvic acid formed in glycolysis and yields high-energy molecules of NADH and Flavin adenine dinucleotide (FADH2), as well as some ATP.

    Krebs Cycle
    Krebs Cycle

    The Krebs cycle occurs in the mitochondrion of a cell (see Figure 6). This sausage-shaped organelle possesses inner and outer membranes and, therefore, inner and outer compartments. The inner membrane is folded over itself many times; the folds are called cristae. They are somewhat similar to the thylakoid membranes in chloroplasts (see Photosynthesis). Located along the cristae are the important enzymes necessary for the proton pump and for ATP production.

    Prior to entering the Krebs cycle, the pyruvic acid molecules are altered. Each three-carbon pyruvic acid molecule undergoes conversion to a substance called acetyl-coenzyme A, or Acetyl-CoA. During the process, the pyruvic acid molecule is broken down by an enzyme, one carbon atom is released in the form of carbon dioxide, and the remaining two carbon atoms are combined with a coenzyme called coenzyme A. This combination forms Acetyl-CoA. In the process, electrons and a hydrogen ion are transferred to NAD to form high-energy NADH.

    Acetyl-CoA enters the Krebs cycle by combining with a four-carbon acid called oxaloacetic acid. The combination forms the six-carbon acid called citric acid. Citric acid undergoes a series of enzyme-catalyzed conversions. The conversions, which involve up to ten chemical reactions, are all brought about by enzymes. In many of the steps, high-energy electrons are released to NAD. The NAD molecule also acquires a hydrogen ion and becomes NADH. In one of the steps, FAD serves as the electron acceptor, and it acquires two hydrogen ions to become FADH2. Also, in one of the reactions, enough energy is released to synthesize a molecule of ATP. Because for each glucose molecule there are two pyruvic acid molecules entering the system, two ATP molecules are formed.

    Also during the Krebs cycle, the two carbon atoms of Acetyl-CoA are released, and each forms a carbon dioxide molecule. Thus, for each Acetyl-CoA entering the cycle, two carbon dioxide molecules are formed. Two Acetyl-CoA molecules enter the cycle, and each has two carbon atoms, so four carbon dioxide molecules will form. Add these four molecules to the two carbon dioxide molecules formed in the conversion of pyruvic acid to Acetyl-CoA, and it adds up to six carbon dioxide molecules. These six CO2 molecules are given off as waste gas in the Krebs cycle. They represent the six carbons of glucose that originally entered the process of glycolysis.

    At the end of the Krebs cycle, the final product is oxaloacetic acid. This is identical to the oxaloacetic acid that begins the cycle. Now the molecule is ready to accept another Acetyl-CoA molecule to begin another turn of the cycle. All told, the Krebs cycle forms (per two molecules of pyruvic acid) two ATP molecules, ten NADH molecules, and two FADH2 molecules. The NADH and the FADH2 will be used in the electron transport system.

    Electron Transport System

    The electron transport system occurs in the cristae of the mitochondria, where a series of cytochromes (enzymes) and coenzymes exist. These cytochromes and coenzymes act as carrier molecules and transfer molecules. They accept high-energy electrons and pass the electrons to the next molecule in the system. At key proton-pumping sites, the energy of the electrons transports protons across the membrane into the outer compartment of the mitochondrion.

    Each NADH molecule is highly energetic, which accounts for the transfer of six protons into the outer compartment of the mitochondrion. Each FADH2 molecule accounts for the transfer of four protons. The flow of electrons is similar to that taking place in photosynthesis. Electrons pass from NAD to FAD, to other cytochromes and coenzymes, and eventually they lose much of their energy. In cellular respiration, the final electron acceptor is an oxygen atom. In their energy-depleted condition, the electrons unite with an oxygen atom. The electron-oxygen combination then reacts with two hydrogen ions (protons) to form a water molecule (H2O).

    The role of oxygen in cellular respiration is substantial. As a final electron acceptor, it is responsible for removing electrons from the electron transport system. If oxygen were not available, electrons could not be passed among the coenzymes, the energy in electrons could not be released, the proton pump could not be established, and ATP could not be produced. In humans, breathing is the essential process that brings oxygen into the body for delivery to the cells to participate in cellular respiration.

    Chemiosmosis

    The actual production of ATP in cellular respiration takes place through the process of chemiosmosis (see Cells and Energy). Chemiosmosis involves the pumping of protons through special channels in the membranes of mitochondria from the inner to the outer compartment. The pumping establishes a proton (H+) gradient. After the gradient is established, protons diffuse down the gradient through a transport protein called ATP synthase. The flow of hydrogens catalyzes the pairing of a phosphate with ADP, forming ATP.

    The energy production of cellular respiration is substantial. Most biochemists agree that 36 molecules of ATP can be produced for each glucose molecule during cellular respiration as a result of the Krebs cycle reactions, the electron transport system, and chemiosmosis. Also, two ATP molecules are produced through glycolysis, so the net yield is 38 molecules of ATP. These ATP molecules may then be used in the cell for its needs. However, the ATP molecules cannot be stored for long periods of time, so cellular respiration must constantly continue in order to regenerate the ATP molecules as they are used. Each ATP molecule is capable of releasing 7.3 kilocalories of energy per mole.

    Fermentation

    Fermentation is an anaerobic process in which energy can be released from glucose even though oxygen is not available. Fermentation occurs in yeast cells, and a form of fermentation takes place in bacteria and in the muscle cells of animals.

    In yeast cells (the yeast used for baking bread and producing alcoholic beverages), glucose can be metabolized through cellular respiration as in other cells. When oxygen is lacking, however, glucose is still metabolized to pyruvic acid via glycolysis. The pyruvic acid is converted first to acetaldehyde and then to ethyl alcohol. The net gain of ATP to the yeast cell is two molecules—the two molecules of ATP normally produced in glycolysis.

    Yeasts are able to participate in fermentation because they have the necessary enzyme to convert pyruvic acid to ethyl alcohol. This process is essential because it removes electrons and hydrogen ions from NADH during glycolysis. The effect is to free the NAD so it can participate in future reactions of glycolysis. The net gain to the yeast cell of two ATP molecules permits it to remain alive for some time. However, when the percentage of ethyl alcohol reaches approximately 15 percent, the alcohol kills the yeast cells.

    Yeast is used in both bread and alcohol production. Alcohol fermentation is the process that yields beer, wine, and other spirits. The carbon dioxide given off during fermentation supplements the carbon dioxide given off during the Krebs cycle and causes bread to rise.

    In muscle cells, another form of fermentation takes place. When muscle cells contract too frequently (as in strenuous exercise), they rapidly use up their oxygen supply. As a result, the electron transport system and Krebs cycle slow considerably, and ATP production is slowed. However, muscle cells have the ability to produce a small amount of ATP through glycolysis in the absence of oxygen. The muscle cells convert glucose to pyruvic acid. An enzyme in the muscle cells then converts the pyruvic acid to lactic acid. As in the yeast, this reaction frees up the NAD while providing the cells with two ATP molecules from glycolysis. Eventually, however, the lactic acid buildup causes intense fatigue, and the muscle stops contracting.

  • Photosynthesis

    What is Photosynthesis?

    A great variety of living things on Earth, including all green plants, synthesize their foods from simple molecules, such as carbon dioxide and water. For this process, the organisms require energy, and that energy is derived from sunlight.

    Figure 1. shows the energy relationships in living cells. Light energy is captured in the chloroplast of plant cells and used to synthesize glucose molecules, shown as C6H12O6. In the process, oxygen (O2) is released as a waste product. The glucose and oxygen are then used in the mitochondrion of the plant cell, and the energy is released and used to fuel the synthesis of ATP from ADP and P. In the reaction, CO2 and water are released in the mitochondrion to be reused in photosynthesis in the chloroplast.

    Energy relationships in living cells Cycles
    Energy relationships in living cells Cycles

    Energy relationships in living cells

    Figure 1. Energy relationships in living cells.

    The process of utilizing energy to synthesize carbohydrate molecules is called photosynthesis. Photosynthesis is actually two separate processes. in the first process, energy-rich electrons flow through a series of coenzymes and other molecules. This electron energy is trapped. During the trapping process, adenosine triphosphate (ATP) molecules and molecules of nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) are formed. Both ATP and NADPH are rich in energy. These molecules are used in the second process, where carbon dioxide molecules are bound into carbohydrates too form organic substances such as glucose.

    Chloroplast

    The organelle in which photosynthesis occurs (in the leaves and green stems of plants, for example) is called the chloroplast. Chloroplasts are relatively large organelles, containing a watery, protein-rich fluid called stroma. The stroma contains many small structures composed of membranes that resemble stacks of coins. Each stack is a granum (the plural form is grana). Each membrane in the stack is a thylakoid. Within the thylakoid membranes of the granum, many of the reactions of photosynthesis take place. The thylakoids are somewhat similar to the cristae of mitochondria (see Cellular Respiration).

    Photosystems

    Pigment molecules organized into photosystems capture sunlight in the chloroplast. Photosystems are clusters of light-absorbing pigments with some associated molecules—proton (hydrogen ion) pumps, enzymes, coenzymes, and cytochromes (see Cells and Energy). Each photosystem contains about 200 molecules of a green pigment called chlorophyll and about 50 molecules of another family of pigments called carotenoids. In the reaction center of the photosystem, the energy of sunlight is converted to chemical energy. The center is sometimes called a light-harvesting antenna.

    There are two photosystems within the thylakoid membranes, designated photosystem I and photosystem II. The reaction centers of these photosystems are P700 and P680, respectively. The energy captured in these reaction centers drives chemiosmosis, and the energy of chemiosmosis stimulates ATP production in the chloroplasts.

    Process of Photosynthesis

    The process of photosynthesis is conveniently divided into two parts: the energy-fixing reaction (also called the light reaction) and the carbon-fixing reaction (also called the light-independent reaction or the dark reaction).

    Energy-fixing reaction

    The energy-fixing reaction of photosynthesis begins when light is absorbed in photosystem II in the thylakoid membranes. The energy of the sunlight, captured in the P680 reaction center, causes the electrons from P680’s chlorophyll to move to a higher, unstable energy level. These electrons pass through a series of cytochromes in the nearby electron-transport system.

    After passing through the electron transport system, the energy-rich electrons eventually enter Photosystem-I. Some of the energy of the electron is used to pump protons across the thylakoid membrane, and this pumping sets up the potential for chemiosmosis.

    The spent electrons from P680 enter the P700 reaction center in photosystem I. Sunlight activates the electrons, which receive a second boost out of the chlorophyll molecules. There they reach a high energy level. The electrons progress through a second electron transport system, but this time there is no proton pumping. Rather, the energy reduces NADP. This reduction occurs as two electrons join NADP and energize the molecule. Because NADP acquires two negatively charged electrons, it attracts two positively charged protons to balance the charges. Consequently, the NADP molecule is reduced to NADPH, a molecule that contains much energy.

    Because electrons have flowed out of the P680 reaction center, the chlorophyll molecules are left without a certain number of electrons. Electrons secured from water molecules replace these electrons. Each split water molecule releases two electrons that enter the chlorophyll molecules to replace those lost. The split water molecules also release two protons that enter the cytoplasm near the thylakoid and are available to increase the chemiosmotic gradient.

    The third product of the split water molecules is oxygen. Two oxygen atoms combine with one another to form molecular oxygen (O2), which is given off as the by-product of photosynthesis; it fills the atmosphere and is used by all oxygen-requiring organisms, including plant and animal cells.

    Described above are the noncyclic energy-fixing reactions (see Figure 2). Certain plants and autotrophic prokaryotes are also known to participate in cyclic energy-fixing reactions. These reactions involve only photosystem I and the P700 reaction center. Excited electrons leave the reaction center, pass through coenzymes of the electron transport system, and follow a special pathway back to P700. Each electron powers the proton pump and encourages the transport of a proton across the thylakoid membrane. This process enriches the proton gradient and eventually leads to the generation of ATP.

    The energy-fixing reactions of photosynthesis

    Figure 2. The energy-fixing reactions of photosynthesis.

    ATP production in the energy-fixing reactions of photosynthesis occurs by the process of chemiosmosis (explained in Cells and Energy). Essentially, this process consists of a rush of protons across a membrane (the thylakoid membrane, in this case), accompanied by the synthesis of ATP molecules. Biochemists have calculated that the proton concentration on one side of the thylakoid is 10,000 times that of the opposite side of the membrane.

    In photosynthesis, the protons pass back across the membranes through channels lying alongside sites where enzymes are located. As the protons pass through the channels, the energy of the protons is released to form high-energy ATP bonds. ATP is formed in the energy-fixing reactions along with the NADPH formed in the main reactions. Both ATP and NADPH provide the energy necessary for the synthesis of carbohydrates that occurs in the second major set of events in photosynthesis.

    Carbon-fixing reaction

    Glucose and other carbohydrates are synthesized in the carbon-fixing reaction of photosynthesis, often called the Calvin cycle after Melvin Calvin, who performed much of the biochemical research (see Figure 3). This phase of photosynthesis occurs in the stroma of the plant cell.

    A carbon-fixing reaction or the Calvin cycle
    A carbon-fixing reaction or the Calvin cycle

    Figure 3. A carbon-fixing reaction, also called the Calvin cycle.

    In the carbon-fixing reaction, an essential material is carbon dioxide, which is obtained from the atmosphere. The carbon dioxide is attached to a five-carbon compound called ribulose bisphosphate. Ribulose bisphosphate carboxylase catalyzes this reaction.

    After carbon dioxide has been joined to ribulose bisphosphate, a six-carbon product forms, which immediately breaks into two three-carbon molecules called phosphoglycerate. Each phosphoglycerate molecule converts to another organic compound, but only in the presence of ATP. The ATP used is the ATP synthesized in the energy-fixing reaction. The organic compound formed converts to still another organic compound using the energy present in NADPH. Again, the energy-fixing reaction provides the essential energy. Each of the organic compounds that results consists of three carbon atoms. Eventually, the compounds interact with one another and join to form a single molecule of six-carbon glucose. This process also generates additional molecules of ribulose bisphosphate to participate in further carbon-fixing reactions.

    Glucose can be stored in plants in several ways. In some plants, the glucose molecules are joined to one another to form starch molecules. Potato plants, for example, store starch in tubers (underground stems). In some plants, glucose converts to fructose (fruit sugar), and the energy is stored in this form. In still other plants, fructose combines with glucose to form sucrose, commonly known as table sugar. The energy is stored in carbohydrates in this form. Plant cells obtain energy for their activities from these molecules. Animals use the same forms of glucose by consuming plants and delivering the molecules to their cells.

    All living things on Earth depend in some way on photosynthesis. It is the main mechanism for bringing the energy of sunlight into living systems and making that energy available for the chemical reactions taking place in cells.

  • Cells and Energy

    What are Cells and Energy?

    The Laws of Thermodynamics; Life can exist only where molecules and cells remain organized. All cells need energys to maintain organization. Physicists define energy as the ability to do work; in this case, the work is the continuation of life itself.

    Energy has been expressed in terms of reliable observations known as the laws of thermodynamics. There are two such laws. The first law of thermodynamics states that energy can neither be created nor destroyed. This law implies that the total amount of energy in a closed system (for example, the universe) remains constant. Energys neither enters nor leaves a closed system.

    Cells and Energy 1

    Within a closed system, energy can change, however. For instance, the chemical energy in gasoline is released when the fuel combines with oxygen and a spark ignites the mixture within a car’s engine. The gasoline’s chemical energy is changed into heat energy, sound energy, and the energy of motion.

    The second law of thermodynamics states that the amount of available energy in a closed system is decreasing constantly. Energy becomes unavailable for use by living things because of entropy, which is the degree of disorder or randomness of a system. The entropy of any closed system is constantly increasing. In essence, any closed system tends toward disorganization.

    Unfortunately, the transfers of energy in living systems are never completely efficient. Every body movement, every thought, and every chemical reaction in the cells involves a shift of energy and a measurable decrease of energy available to do work in the process. For this reason, considerably more energy must be taken into the system than is necessary to carry out the actions of life.

    Chemical Reactions

    Most chemical compounds do not combine with one another automatically, nor do chemical compounds break apart automatically. The great majority of the chemical reactions that occur within living things must be energized. This means that the atoms of a molecule must be separated by energy put into the system. The energy forces apart the atoms in the molecules and allows the reaction to take place.

    To initiate a chemical reaction, a type of “spark,” referred to as the energy of activation, is needed. For example, hydrogen and oxygen can combine to form water at room temperature, but the reaction requires activation energy.

    Any chemical reaction in which energy is released is called an exergonic reaction. In an exergonic chemical reaction, the products end up with less energy than the reactants. Other chemical reactions are endergonic reactions. In endergonic reactions, energy is obtained and trapped from the environment. The products of endergonic reactions have more energy than the reactants taking part in the chemical reaction. For example, plants carry out the process of photosynthesis, in which they trap energy from the sun to form carbohydrates (see Photosynthesis).

    The activation energy needed to spark an exergonic or endergonic reaction can be heat energy or chemical energy. Reactions that require activation energy can also proceed in the presence of biological catalysts. Catalysts are substances that speed up chemical reactions but remain unchanged themselves. Catalysts work by lowering the required amount of activation energy for the chemical reaction. For example, hydrogen and oxygen combine with one another in the presence of platinum. In this case, platinum is the catalyst. In biological systems, the most common catalysts are protein molecules called enzymes. Enzymes are absolutely essential if chemical reactions are to occur in cells.

    Enzymes

    The chemical reactions in all cells of living things operate in the presence of biological catalysts called enzymes. Because a particular enzyme catalyzes only one reaction, there are thousands of different enzymes in a cell catalyzing thousands of different chemical reactions. The substance changed or acted on by an enzyme is its substrate. The products of a chemical reaction catalyzed by an enzyme are end products.

    All enzymes are composed of proteins. (Proteins are chains of amino acids; see The Chemical Basis of Life.) When an enzyme functions, a key portion of the enzyme, called the active site, interacts with the substrate. The active site closely matches the molecular configuration of the substrate. After this interaction has taken place, a change in shape in the active site places a physical stress on the substrate. This physical stress aids the alteration of the substrate and produces the end products. During the time the active site is associated with the substrate, the combination is referred to as the enzyme-substrate complex. After the enzyme has performed its work, the product or products are released from the enzyme’s active site. The enzyme is then free to function in another chemical reaction.

    Enzyme-catalyzed reactions occur extremely fast. They happen about a million times faster than uncatalyzed reactions. With some exceptions, the names of enzymes end in “–ase.” For example, the enzyme that breaks down hydrogen peroxide to water and hydrogen is catalase. Other enzymes include amylase, hydrolase, peptidase, and kinase.

    The rate of an enzyme-catalyzed reaction depends on a number of factors, such as the concentration of the substrate, the acidity and temperature of the environment, and the presence of other chemicals. At higher temperatures, enzyme reactions occur more rapidly, but only up to a point. Because enzymes are proteins, excessive amounts of heat can change their structures, rendering them inactive. An enzyme altered by heat is said to be denatured.

    Enzymes work together in metabolic pathways. A metabolic pathway is a sequence of chemical reactions occurring in a cell. A single enzyme-catalyzed reaction may be one of multiple reactions in a metabolic pathway. Metabolic pathways may be of two general types: catabolic and anabolic. Catabolic pathways involve the breakdown or digestion of large, complex molecules. The general term for this process is catabolism. Anabolic pathways involve the synthesis of large molecules, generally by joining smaller molecules together. The general term for this process is anabolism.

    Many enzymes are assisted by chemical substances called cofactors. Cofactors may be ions or molecules associated with an enzyme and are required in order for a chemical reaction to take place. Ions that might operate as cofactors include those of iron, manganese, and zinc. Organic molecules acting as cofactors are referred to as coenzymes.

    Adenosine Triphosphate (ATP)

    Adenosine Triphosphate (ATP)

    The chemical substance that serves as the currency of energy in a cell is adenosine triphosphate (ATP). ATP is referred to as currency because it can be “spent” in order to make chemical reactions occur. The more energy required for a chemical reaction, the more ATP molecules must be spent.

    Virtually all forms of life use ATP, a nearly universal molecule of energy transfer. The energy released during catabolic reactions is stored in ATP molecules. In addition, the energy trapped in anabolic reactions (such as photosynthesis) is trapped in ATP molecules.

    An ATP molecule consists of three parts. One part is a double ring of carbon and nitrogen atoms called adenine. Attached to the adenine molecule is a small five-carbon carbohydrate called ribose. Attached to the ribose molecule are three phosphate units linked together by covalent bonds.

    Adenosine Triphosphate Structure
    Adenosine Triphosphate Structure

    The covalent bonds that unite the phosphate units in ATP are high-energy bonds. When an ATP molecule is broken down by an enzyme, the third (terminal) phosphate unit is released as a phosphate group, which is an ion. When this happens, approximately 7.3 kilocalories of energy are released. (A kilocalorie equals 1,000 calories.) This energy is made available to do the work of the cell.

    The adenosine triphosphatase enzyme accomplishes the breakdown of an ATP molecule. The products of ATP breakdown are adenosine diphosphate (ADP) and a phosphate ion. Adenosine diphosphate and the phosphate ion can be reconstituted to form ATP, much like a battery can be recharged. To accomplish this, synthesis energy must be available. This energy can be made available in the cell through two extremely important processes: photosynthesis.

    ATP Production

    ATP is generated from ADP and phosphate ions by a complex set of processes occurring in the cell. These processes depend on the activities of a special group of coenzymes. Three important coenzymes are nicotinamide adenine dinucleotide (NAD), nicotinamide adenine dinucleotide phosphate (NADP), and Flavin adenine dinucleotide (FAD).

    NAD and NADP are structurally similar to ATP. Both molecules have a nitrogen-containing ring called nicotinic acid, which is the chemically active part of the coenzymes. In FAD, the chemically active portion is the Flavin group. The vitamin riboflavin is used in the body to produce this Flavin group.

    All coenzymes perform essentially the same work. During the chemical reactions of metabolism, coenzymes accept electrons and pass them on to other coenzymes or other molecules. The removal of electrons or protons from a coenzyme is oxidation. The addition of electrons to a molecule is reduction. Therefore, the chemical reactions performed by coenzymes are called oxidation-reduction reactions.

    The oxidation-reduction reactions performed by the coenzymes and other molecules are essential to the energy metabolism of the cell. Other molecules participating in this energy reaction are called cytochromes. Together with the coenzymes, cytochromes accept and release electrons in a system called the electron transport system. The passage of energy-rich electrons among cytochromes and coenzymes drains the energy from the electrons to form ATP from ADP and phosphate ions.

    The actual formation of ATP molecules requires a complex process called chemiosmosis. Chemiosmosis involves the creation of a steep proton (hydrogen ion) gradient. This gradient occurs between the membrane-bound compartments of the mitochondria of all cells and the chloroplasts of plant cells. A gradient is formed when large numbers of protons (hydrogen ions) are pumped into the membrane-bound compartments of the mitochondria. The protons build up dramatically within the compartment, finally reaching an enormous number. The energy released from the electrons during the electron transport system pumps the protons.

    After large numbers of protons have gathered within the compartments of mitochondria and chloroplasts, they suddenly reverse their directions and escape back across the membranes and out of the compartments. The escaping protons release their energy in this motion. This energy is used by enzymes to unite ADP with phosphate ions to form ATP. The energy is trapped in the high-energy bond of ATP by this process, and the ATP molecules are made available to perform cell work. The movement of protons is chemiosmosis because it is a movement of chemicals (in this case, protons) across a semipermeable membrane. Because chemiosmosis occurs in mitochondria and chloroplasts, these organelles play an essential role in the cell’s energy metabolism. Photosynthesis explains how energy is trapped in the chloroplasts in plants, while Cellular Respiration explains how energy is released in the mitochondria of plant and animal cells.

  • What is The Chemical Basis of Life?

    What is The Chemical Basis of Life?

    Understanding of Chemical; A chemical substance is a form of matter that has the constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be chemical elements, chemical compounds, ions or alloys.

    Chemical substances are often called ‘pure’ to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are the diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical.

    Chemical substances exist as solids, liquids, gases, or plasma, and may change between these phases of matter with changes in temperature or pressure. Chemical substances may be combined or converted to others by means of chemical reactions. Now you will understanding of The Chemical Basis of Life.

    Acids and Bases

    Acids are chemical compounds that release hydrogen ions (H+) when placed in water. For example, when hydrogen chloride is placed in water, it releases its hydrogen ions and the solution becomes hydrochloric acid.

    Bases are chemical compounds that attract hydrogen atoms when they are placed in water. An example of a base is sodium hydroxide (NaOH). When this substance is placed in water, it attracts hydrogen ions, and a basic (or alkaline) solution results as hydroxyl (–OH) ions accumulate.

    Molecule

    Most of the compounds of interest to biologists are composed of units called molecules. A molecule is a precise arrangement of atoms held together by chemical bonds, and a compound is a molecule that contains atoms of more than one element. A molecule may be composed of two or more atoms of the same element, as in oxygen gas (O2), or it may be composed of atoms from different elements. The arrangements of the atoms in a molecule account for the properties of a compound. The molecular weight is equal to the atomic weights of the atoms in the molecule.

    The atoms in molecules may be joined to one another by various linkages called bonds. One example of a bond is an ionic bond, which is formed when the electrons of one atom transfer to a second atom. This creates electrically charged atoms called ions. The electrical charges cause the ions to be attracted to one another, and the attraction forms the ionic bond.

    A second type of linkage is a covalent bond. A covalent bond forms when two atoms share one or more electrons with one another. For example, as shown in Figure 1, oxygen shares its electrons with two hydrogen atoms, and the resulting molecule is water (H2O). Nitrogen shares its electrons with three hydrogen atoms, and the resulting molecule is ammonia (NH3). If one pair of electrons is shared, the bond is a single bond; if two pairs are shared, it is a double bond.

    Formation of a covalent bond in water and ammonia molecules

    Figure 1. Formation of a covalent bond in water and ammonia molecules. In each molecule, the second shell fills with eight electrons.

    Organic Compound: The chemical compounds of living things are known as organic compounds because of their association with organisms and because they are carbon-containing compounds. Organic compounds, which are the compounds associated with life processes, are the subject matter of organic chemistry. Among the numerous types of organic compounds, four major categories are found in all living things: carbohydrates, lipids, proteins, and nucleic acids.

    Carbohydrates

    Almost all organisms use carbohydrates as sources of energy. In addition, some carbohydrates serve as structural materials. Carbohydrates are molecules composed of carbon, hydrogen, and oxygen; the ratio of hydrogen atoms to oxygen and carbon atoms is 2:1.

    Simple carbohydrates, commonly referred to as sugars, can be monosaccharides if they are composed of single molecules, or disaccharides if they are composed of two molecules. The most important monosaccharide is glucose, a carbohydrate with the molecular formula C6H12O6. Glucose is the basic form of fuel in living things. In multicellular organisms, it is soluble and is transported by body fluids to all cells, where it is metabolized to release its energy. Glucose is the starting material for cellular respiration, and it is the main product of photosynthesis

    Three important disaccharides are also found in living things: maltose, sucrose, and lactose. Maltose is a combination of two glucose units covalently linked. The table sugar sucrose is formed by linking glucose to another monosaccharide called fructose. (Figure 2 shows that in the synthesis of sucrose, a water molecule is produced. The process is therefore called a dehydration reaction. The reversal of the process is hydrolysis, a process in which the molecule is split and water is added.) Lactose is composed of glucose and galactose units.

    Glucose and fructose molecules combine to form the disaccharide sucrose

    Figure 2. Glucose and fructose molecules combine to form the disaccharide sucrose.

    Complex carbohydrates are known as polysaccharides. Polysaccharides are formed by linking innumerable monosaccharides. Among the most important polysaccharides is starch, which is composed of hundreds or thousands of glucose units linked to one another. Starch serves as a storage form for carbohydrates. Much of the world’s human population satisfies its energy needs with starch in the form of rice, wheat, corn, and potatoes.

    Two other important polysaccharides are glycogen and cellulose. Glycogen is also composed of thousands of glucose units, but the units are bonded in a different pattern than in starch. Glycogen is the form in which glucose is stored in the human liver. Cellulose is used primarily as a structural carbohydrate. It is also composed of glucose units, but the units cannot be released from one another except by a few species of organisms. Wood is composed chiefly of cellulose, as are plant cell walls. Cotton fabric and paper are commercial cellulose products.

    Lipids

    Lipids are organic molecules composed of carbon, hydrogen, and oxygen atoms. The ratio of hydrogen atoms to oxygen atoms is much higher in lipids than in carbohydrates. Lipids include steroids (the material of which many hormones are composed), waxes, and fats.

    Fat molecules are composed of a glycerol molecule and one, two, or three molecules of fatty acids (see Figure 3). A glycerol molecule contains three hydroxyl (–OH) groups. A fatty acid is a long chain of carbon atoms (from 4 to 24) with a carboxyl (–COOH) group at one end. The fatty acids in a fat may all be alike or they may all be different. They are bound to the glycerol molecule by a process that involves the removal of water.

    Certain fatty acids have one or more double bonds in their molecules. Fats that include these molecules are unsaturated fats. Other fatty acids have no double bonds. Fats that include these fatty acids are saturated fats. In most human health situations, the consumption of unsaturated fats is preferred to the consumption of saturated fats.

    Fats stored in cells usually form clear oil droplets called globules because fats do not dissolve in water. Plants often store fats in their seeds, and animals store fats in large, clear globules in the cells of adipose tissue. The fats in adipose tissue contain much concentrated energy. Hence, they serve as a reserve energy supply to the organism. The enzyme lipase breaks down fats into fatty acids and glycerol in the human digestive system.

    A fat molecule is constructed by combining a glycerol molecule with three fatty acid molecules

    Figure 3. A fat molecule is constructed by combining a glycerol molecule with three fatty acid molecules. (Two saturated fatty acids and one unsaturated fatty acid are shown for comparison.) The constructed molecule is at the bottom.

    Protein

    Proteins, among the most complex of all organic compounds, are composed of amino acids (see Figure 4), which contain carbon, hydrogen, oxygen, and nitrogen atoms. Certain amino acids also have sulfur atoms, phosphorus, or other trace elements such as iron or copper.

    The structure and chemistry of amino acids

    Figure 4. The structure and chemistry of amino acids. When two amino acids are joined in a dipeptide, the –OH of one amino acid is removed, and the –H of the second is removed. So, water is removed. A dipeptide bond (right) forms to join the amino acids together

    Many proteins are immense and extremely complex. However, all proteins are composed of long chains of relatively simple amino acids. There are 20 kinds of amino acids. Each amino acid (see the left illustration in Figure 4) has an amino (–NH2) group, a carboxyl (–COOH) group, and a group of atoms called an –R group (where R stands for radical). The amino acids differ depending on the nature of the –R group, as shown in the middle illustration of Figure 4. Examples of amino acids are alanine, valine, glutamic acid, tryptophan, tyrosine, and histidine.

    The removal of water molecules links amino acids to form a protein. The process is called dehydration synthesis, and a by-product of the synthesis is water. The links forged between the amino acids are peptide bonds, and small proteins are often called peptides.

    All living things depend on proteins for their existence. Proteins are the major molecules from which living things are constructed. Certain proteins are dissolved or suspended in the watery substance of the cells, while others are incorporated into various structures of the cells. Proteins are also found as supporting and strengthening materials in tissues outside of cells. Bone, cartilage, tendons, and ligaments are all composed of proteins.

    One essential function of proteins is as an enzyme. Enzymes catalyze the chemical reactions that take place within cells. They are not used up in a reaction; rather, they remain available to catalyze succeeding reactions.

    Every species manufactures proteins unique to that species. The information for synthesizing the unique proteins is located in the nucleus of the cell. The so-called genetic code specifies the amino acid sequence in proteins. Hence, the genetic code regulates the chemistry taking place within a cell. Proteins also can serve as a reserve source of energy for the cell. When the amino group is removed from an amino acid, the resulting compound is energy-rich.

    Nucleic acids: Like proteins, nucleic acids are very large molecules. The nucleic acids are composed of smaller units called nucleotides. Each nucleotide contains a carbohydrate molecule (sugar), a phosphate group, and a nitrogen-containing molecule that, because of its properties, is a nitrogenous base.

    Living organisms have two important nucleic acids. One type is deoxyribonucleic acid, or DNA. The other is ribonucleic acid, or RNA. DNA is found primarily in the nucleus of the cell, while RNA is found in both the nucleus and the cytoplasm, a semiliquid substance that composes the volume of the cell.

    DNA and RNA differ from one another in their components. DNA contains the carbohydrate deoxyribose, while RNA has ribose. In addition, DNA contains the base thymine, while RNA has uracil.

    Elements and Atoms

    For many centuries, biology was the study of the natural world. Biologists searched for unidentified plants and animals, classified them, and studied their anatomy and how they acted in nature. Then in the 1700s, scientists discovered the chemical and physical bases of living things. They soon realized that the chemical organization of all living things is remarkably similar.

    Elements: All living things on Earth are composed of fundamental building blocks of matter called elements. More than 100 elements are known to exist, including those that are man-made. An element is a substance that cannot be chemically decomposed. Oxygen, iron, calcium, sodium, hydrogen, carbon, and nitrogen are examples of elements.

    Atoms: Each element is composed of one particular kind of atom. An atom is the smallest part of an element that can enter into combinations with atoms of other elements.

    Atoms consist of positively charged particles called protons surrounded by negatively charged particles called electrons. A third type of particle, a neutron, has no electrical charge; it has the same weight as a proton. Protons and neutrons adhere tightly to form the dense, positively charged nucleus of the atom. Electrons spin around the nucleus.

    The electron arrangement in an atom plays an essential role in the chemistry of the atom. Atoms are most stable when their outer shell of electrons has a full quota. The first electron shell has a maximum of two electrons. The second and all other outer shells have a maximum of eight electrons. Atoms tend to gain or lose electrons until their outer shells have a stable arrangement. The gaining or losing of electrons, or the sharing of electrons, contributes to the chemical reactions in which an atom participates.