Meaning of helpless: “Unable to defend oneself or to act without help.” A student who has a history of failure and does not expect this to change will attribute failure to ability an internal and stable factor. This pattern is characteristic of students classified as having learned helplessness. These individuals expect that their actions will be futile in affecting future outcomes. Consequently, they give up. Learned helplessness was first investigated in young animals who had been presented with inescapable electric shocks in one situation; when placed in a different situation, they failed to try to escape or avoid the shock (Seligman & Maier, 1967). Animals that demonstrated no connection between their activity and avoiding the shock had learned to be helpless. It was further hypothesized that humans responded the same way: they were passive in situations where they believed their actions would have no effect on what happens to them. In this original explanation, helplessness was viewed as global affecting all domains of one’s life. Later research found that people may experience helplessness in one situation and not in others (Alloy, Abramson, Peterson, & Seligman, 1984). This means that a student may feel helpless in learning math but not in learning history.
Helplessness exists in achievement situations when students do not see a connection between their actions and their performance and grades. The important aspect of learned helplessness is how it affects the motivational behavior of students in the face of failure. The attributions a student makes for failure act as a bridge between a student’s willingness to try again and the student’s tendency to give up.
Helpless and Mastery Orientation
In a now-classic study, Diener and Dweck (1978) identified two patterns of responses to failure following success in problem-solving tasks: a maladaptive-helpless orientation and an adaptive-mastery orientation. Children showed different response patterns to failure in their thinking, self-talk, affect, and actions. Keep in mind that the students in the study had the same failure experience while performing the tasks, but there were two different patterns of response to the failure outcome. The thinking, self-talk, and actions of the helpless-oriented children formed a self-defeating pattern. When failure is attributed to lack of ability, there is a decline in performance. Attribution to lack of effort does not show this decline (Dweck & Goetz, 1978).
Are there ability differences in learned helplessness? Butkowsky and Willows (1980) compared good, average, and poor readers. They found that poor readers had lower expectancies of success on a reading task. Poor readers overwhelmingly attributed their failures to lack of ability (68% compared with 13% for average readers and 12% for good readers). They took less responsibility for success, attributing success more to task ease an external cause than did the good and average readers. In the face of difficulty, poor readers became less persistent a self-defeating behavior. Helplessness was also found when children studied new material that required them to read passages with confusing concepts.
In a study by Licht and Dweck (1984), half the children received material with a clear passage, and the other half received a confusing passage. There were no differences between mastery orientation and helpless orientation when the passage was clearly written. In contrast, when the passage was not clear, most of the mastery children reached the learning criterion, whereas only one third of the helpless children did. This investigation is important because some academic subjects, like math, are characterized by constant new learning, which may be initially confusing to students. Mastery students will not be discouraged by the initial difficulty, whereas helpless students immediately lose confidence although they may be equally competent. When teaching new material, teachers can be especially alert for this pattern of helplessness in the face of initial difficulty.
Learned Helplessness and Students with Learning Disabilities
Are some students more prone to experience a sense of helplessness? Students particularly susceptible to the pattern of learned helplessness are those students who are identified as having learning disabilities (LD) (Licht, 1983). Children with LD experience much failure over a long period of time on a variety of school tasks. As a result, these children come to doubt their academic abilities, with the accompanying belief that nothing they can do will help them be successful. This is followed by the self-defeating response of decreasing effort. Children with LD have been found to exhibit the following characteristics of the learned helplessness pattern (Licht, 1983):
Score lower than non-LD children on measures of self-esteem and perceptions of ability,
Are more likely to attribute difficulty with tasks to lack of ability,
Are less likely to attribute failure to insufficient effort, and
Lower their expectations for future success and display greater decline in expectation following failure.
It is important for teachers to be aware of the characteristics of helplessness because learned helplessness may explain the students’ apparent lack of motivation. How can a teacher identify a helpless pattern? What can a teacher do to lessen the likelihood of helplessness and help students who have this tendency? Butkowsky and Willows (1980) suggested that educators must begin to rethink failure as a necessary component of the learning process and not as a damaging experience to be avoided.
Does the pattern of learned helplessness show up in young children? Dweck and Sorich (1999) concluded that there is clear evidence of a helplessness pattern in children younger than age 8. After experiencing failure or criticism, they show signs of helplessness like self-blame, lowered persistence, and lack of constructive strategies. Mastery-oriented children, in contrast, assumed they were still good even when their work had errors, and believed they could improve through effort. An important implication for parents and teachers, according to the authors, is to be very cautious when giving feedback to children. Extremely positive or negative feedback can be detrimental to children’s beliefs about their competence.
Understanding of Attribution and Motivation Among Ethnicity?
What is Ethnicity? Meaning of Ethnicity “The fact or state of belonging to a social group that has a common national or cultural tradition.” Some about of Ethnic; Relating to a population subgroup (within a larger or dominant national or cultural group) with a common national or cultural tradition. Relating to national and cultural origins. Denoting origin by birth or descent rather than by present nationality. Characteristic of or belonging to a non-Western cultural tradition.
An ethnic group or ethnicity is a category of people who identify with each other based on similarities, such as common ancestral, language, social, cultural or national experiences. Unlike other social groups (wealth, age, hobbies), ethnicity is often an inherited status based on the society in which one lives. In some cases, it can be adopted if a person moves into another society. Membership of an ethnic group tends to be defined by a shared cultural heritage, ancestry, origin myth, history, homeland, language or dialect, symbolic systems such as religion, mythology and ritual, cuisine, dressing style, art, and physical appearance.
Ethnic groups, derived from the same historical founder population, often continue to speak related languages and share a similar gene pool. By way of language shift, acculturation, adoption and religious conversion, it is sometimes possible for individuals or groups to leave one ethnic group and become part of another (except for ethnic groups emphasizing racial purity as a key membership criterion).
Ethnicity is often used synonymously with ambiguous terms such as nation or people. In English, it can also have the connotation of something exotic (cf. “White ethnic”, “ethnic restaurant”, etc.), generally related to cultures of more recent immigrants, who arrived after the founding population of an area was established.
Now reading – Attribution and Motivation Among Ethnicity; Do attributional explanations for success and failure act as an important motivational force in different ethnic groups? According to Graham (1989,1994), because attributional theory considers the role of thought in determining behavior, it is particularly fruitful in examining motivation in different cultures and ethnic groups.
Beliefs About Effort and Ability
Are attributional belief patterns similar among different ethnic groups? A comparison of poor African-American, Hispanic, Indo-Chinese, and White fifth- and sixth-grade students found similar attribution patterns for all groups (Bempechat, Nakkula, Wu, & Ginsberg, 1996). All groups rated ability as the most important factor for success in math. In a subsequent study comparing African-American, Hispanic, Indo-Chinese, and White fifthand sixth-graders, Bempechat, Graham, and Jimenez (1999) found cultural similarities as well as cultural specifics. For all ethnic groups, failure was attributed to lack of ability and success to external factors. In contrast, Indo-Chinese students had stronger beliefs that failure was due to lack of effort. Attribution for failure due to lack of ability is a problem for all students because it is believed to be uncontrollable.
Graham (1984) compared middle- and low-SES African-American and White students on attributions for failure following a problem-solving task. The middle-class children in both ethnic groups were more likely to attribute failure to lack of effort and maintained consistently higher expectancies for success after experiencing failure. For both groups, this is indicative of an adaptive attributional pattern following failure, similar to that found in research by Diener and Dweck (1978). The findings of this research are important because they demonstrate the positive motivation pattern of African-American students—a pattern that has received little attention.
Stevenson and Lee (1990) compared beliefs of American and Asian students concerning the role of effort and ability for success in mathematics. They asked mothers in Minnesota, Japan, and Taiwan to assign 10 points among ability, effort, task difficulty, and luck to rank their importance in academic success and school performance. All the mothers assigned the points in the same rank order: (1) effort, (2) ability, (3) task, and (4) luck. American mothers scored ability and effort as about equal. In contrast, Taiwanese and Japanese mothers assigned effort a higher value than ability. Peak (1993) noted that, in Japanese elementary schools, ability is rarely mentioned, whereas effort is consistently portrayed as key to success. In contrast, in the United States, students who try very hard are often labeled nerd or grind.
These perceptions of effort and ability take on increased importance when homework is considered in the context of effort. Japanese and Chinese students spend at least twice the amount of time and effort on homework than do American students (Stevenson & Lee, 1990). American teachers assign less and consider it less valuable. Peak (1993) pointed out that homework reflects teachers’ beliefs on whether extra practice makes a difference and whether students are willing to engage in extra effort on behalf of their studies. American parents do not appear to consider good study habits as critical to academic success as do Asian parents.
Implications for Teachers
What can teachers draw from the attributional beliefs among different ethnic groups in terms of classroom practice? The important issue is to understand the motivational processes, such as attribution, operating within a particular ethnic group (Bempechat et al., 1996; Graham, 1994). When similarities are found across ethnic groups, educational interventions do not necessarily have to be targeted to children differentially based on their ethnic group membership.
Graham (1989) emphasized the importance of teacher feedback in influencing concepts of ability and expectations of minority, low-SES students. Recall the previous discussion of indirect attributional cues. It is important to be aware of feedback that may indirectly convey to students that they have low ability. Graham (1994) suggested that in view of the number of African- American children in negative educational situations, it is especially important to be sensitive to how minorities feel, think, and act in response to non-attainment of goals.
How do we decide what caused our success and failure? What cues do we use to explain whether an outcome was influenced by our ability, effort, or some other factor? Information comes from direct and indirect cues (Graham, 1991). Some information comes from direct cues, like failing a test when other students succeeded. Information is also obtained from more indirect cues, often conveyed unintentionally, such as when a teacher communicates pity to a student who failed a test. In addition, there may be a bias toward causes (Weiner, 1992).
Direct Attributional Cues
One of the most important informational cues is the outcome of the task. Here students have a direct cue as to their performance. Another source of attributional information comes from comparing one’s performance to that of others (Weiner, 1992). When most of the class fails a test, students are likely to attribute the failure to the difficulty of the task, not to their ability. However, if Sam failed and everyone else in the class made an A or B, he is likely to believe the failure was due to his low ability. If Sarah fails a test and a peer says, “I didn’t study at all and I made an A,” Sarah may take this as a cue that failure must be due to her ability. When a teacher sees students comparing grades on a test, information other than the test score is being communicated. An important role of the teacher is to help students interpret the possible reasons for test scores and make an adaptive attribution.
Indirect Attributional Cues
In school, feedback that students receive from teachers is a source of much information about ability. Students’ attributional interpretations may be based on the attributions that teachers communicated to them (Reyna, 2000). Graham (1991) identified three groups of feedback as sources of indirect cues: praise versus blame, sympathy versus anger, and help versus neglect.
Praise Versus Blame: The praise or blame a student receives from a teacher can function as an indirect low-ability cue (Graham, 1991). The cue provided by praise or blame interacts with the difficulty of the task and effort expended by a student. Praise acts as a low-ability cue when a student is praised for completing an easy task. A low-ability cue is also conveyed when a student fails a task but receives no blame, like lack of effort. The student can interpret this to mean, “There’s nothing I can do about the failure.”
Sympathy Versus Anger: Did it ever occur to you that communicating sympathy to a student could be interpreted as evidence that he or she has the low ability? Graham (1984) found that when teachers conveyed sympathy following poor student performance, the failing students took this as a cue that they had low ability. Obviously a statement like “I feel sorry for you because you made such a low score” would be a low-ability cue. What might a teacher say that unintentionally conveys a message of low ability to a student? One student remembers a class being told, “All students have to do this except Holly and Ramon.” Holly took her omission as a cue that she would not be able to do the task. In contrast, mild anger for failure can provide an indirect cue that one is capable. For example, “You can do better than this. You handed this paper in with no editing,” provides a cue to the student that he or she is capable of more.
Unsolicited Help: Another low-ability cue for students is unsolicited help by the teacher (Graham & Barker, 1990). Graham and Barker found that, regardless of whether a helper was a peer or teacher, other students judged the student who received unsolicited help as lower in ability than non-helped peers. The important factor in this example is unsolicited. When the teacher consistently gives help to Sylvia before she requests it, this suggests that the teacher knows that she will not be able to do it.
Ability Grouping: One powerful cue for ability that affects large groups of students are tracking according to ability groups. Students in both high and low tracks are defined by labels such as high ability, honors, low-achieving, slow, and average (Oakes, 1985). These labels are powerful cues about one’s ability. Oakes observed that students in the lower track are usually seen by others as dumb and also see themselves in this way. A label may have an adverse effect on students in the high-achieving class as well. Students in a high-track class may take this label as a cue that they naturally have high ability and then assume inflated self-concepts. This belief can interfere with students working to develop their academic skills.
It is important that teachers be aware of the subtle cues that may have unintentional effects on students’ perception of ability. Commonly accepted practices of generous praise, minimal blame, sympathy, and unsolicited help can sometimes be interpreted by students as they have the low ability (M. D. Clark, 1997; Graham, 1991). M. D. Clark found that responses given to students with LD are often interpreted as low-ability cues. Graham further suggested that these cues raise important questions pertinent to the motivation of minority students such as African-Americans. For example, are minority students more likely to be targeted for feedback that conveys sympathy—thus receiving a cue for low ability? Reyna (2000) took this a step further, stating that labeling and indirect cues can lead to stable beliefs about ability and have the negative effect of stereotyping.
Attribution Bias
Attribution bias or Attributional bias is a predisposition to make certain attributional judgments that may be in error (Weiner, 1985). Several variations of attributional bias have been identified that are relevant to achievement settings. A common misjudgment is a hedonic bias, the tendency to attribute success to self rather than to attribute failure to self (Weiner, 2000).
Previous knowledge can also lead to attributions that are erroneous (Frieze, 1980). Potential sources of errors in attributional judgments can be found in stereotypes about certain groups (Reyna, 2000). These preconceptions about certain groups can serve as ready-made explanations for why a student achieves or does not achieve. There is a danger that the stable, uncontrollable attribution for low performance will lead to lower expectations.
The implication for educators is to recognize that a number of possible causes may explain any given success or failure. Thus, it is important to be aware of potential stereotypical attributional biases. Explore other possible causes by gathering more information when bias may be a factor (see Strategy).
Strategy of Collect Attributional Information
Simply ask students why they succeeded, failed, or improved.
Some teachers elicit information by having students give their reasons for how well they did after assignments or exams.
Attribution information can be obtained through the use of learning logs, in which students keep records and write about their goals, successes, and failures.
Conduct an attributional task analysis of student performance. Is it because the student cannot or will not? A teacher may believe that a student is not performing well because he or she has the low ability or is lazy. Instead, the student may be performing low because he or she does not have the essential skills.
Look for clues that will enable you to determine if the student has the essential skills. Does the student have prerequisite knowledge or skills? Does the task require formal reasoning whereas the student is functioning at the concrete reasoning level? Does the student have the necessary learning or memory strategies?
If the student cannot, then teach the prerequisite skill or guide student to the appropriate source of help.
The ability to concentrate is a skill that becomes stronger over time. Through constant practice, you will be able to concentrate more effectively for an extended period of time. However, if you constantly find it difficult to focus on tasks, or if you find yourself wasting your time on unimportant activities, then you need to address this problem as soon as possible.
Ability: Human Resource Management; An acquired or natural capacity or talent that enables an individual to perform a particular job or task successfully. See also aptitude. Law; The power to carry out a legal act or satisfy a legal obligation.
Concentrate: A concentrate is a form of substance which has had the majority of its base component (in the case of a liquid: the solvent) removed. Typically, this will be the removal of water from a solution or suspension, such as the removal of water from fruit juice. One benefit of producing a concentrate is that of a reduction in weight and volume for transportation, as the concentrate can be reconstituted at the time of usage by the addition of the solvent. Completely different to clustered.
The good news is that there are tested-and-proven tips on how you can concentrate better. Apply the following tips and notice how you will then be able to finish your important tasks on time.
Eliminate distractions
Distractions come in all shapes and sizes. It could be the uncomfortable chair you are sitting on, the messy desk you have to work on, or the loud noises from outside. Whatever your case may be, it is important to get rid of them before you begin your task. That way, you can no longer use them as an excuse to procrastinate.
Here are some suggestions:
I. Hang up a “do not disturb” sign.
II. Play instrumental “concentration enhancing” music to drown out the background noise.
III. Set your phone on silent mode and store it away.
IV. Block certain websites that keep you from focusing.
Focus on one task at a time
Multi-tasking keeps you from being able to provide quality output. It also stresses your mind out, whether you are aware of it or not. This is because you are not really “accomplishing” multiple things at once, but rather you are rapidly switching from one task to another.
Instead, set aside a time block for a particular task and do absolutely nothing else except that task within that time frame. You could even set a timer so that you will not have to glance at the clock every now and then to check how much time you have left.
Take short breaks between tasks
Most people – even the most productive ones out there – can concentrate on an important task for no more than two hours at a time. Likewise, it takes approximately fifteen minutes of rest to replenish this concentration “energy.” Therefore, you can use this as a rule of thumb to schedule breaks.
For instance, after working non-stop on a task for two hours straight, set a timer to signal you to take a fifteen-minute break. Then, do something relaxing, such as taking a walk or having a snack. After fifteen minutes, you will be ready to take on another two-hour long task, give or take.
Focus on challenging tasks during your peak hours
Identify which part of the day you feel most confident and energized, and use this time to work on the tasks that require the most concentration. For most people, mornings are the times when they feel as if they can handle anything. For others, this happens during the evenings when everyone else is exhausted from work.
Reward yourself after accomplishing a challenging task
Our minds are programmed to repeat a certain behavior if we are rewarded for it. Therefore, to condition yourself to practice improving your concentration each day, do not forget to reward yourself after a job well done. It could be something as simple as playing a video game for an hour, watching an episode of your favorite television show, or enjoying a delicious, albeit sinful, snack. That way, you can be more driven to finish the task so that you can get your reward.
Aside from these tips, it always helps to remind yourself to take good care of your body. Always make it a priority to get enough hours of sleep, eat nutritious meals, and hydrate throughout the day. When your body is healthy and full of energy, it is only natural for your mind to be sharp and focused.
At this point, you must be excited to start working on your tasks. However, you might want to learn how to manage your schedule first, especially if you have multiple tasks to handle each day. Find out how you can acquire this skill in the post What is Master the Art of Scheduling?
Efficient (of a system or machine) achieving maximum productivity with minimum wasted effort or expense, preventing the wasteful use of a particular resource. Working in a well-organized and competent way. Performing or functioning in the best possible manner with the least waste of time and effort; having and using requisite knowledge, skill, and industry.
Abraham Lincoln once gave a sound piece of advice regarding productivity. He said, “Give me six hours to chop down a tree and I will spend the first four sharpening the Axe.”
It is apparent that he means that he can do a much more efficient job with the right tool. On the other hand, chopping away on the tree with a dull Axe might cut it down as well, but less efficiently and probably for a longer period of time. In other words, the best way to make the most of your time is by establishing an efficient system. To be more specific, you should first create the most conducive environment, and choosing the best tools, for the task.
To help you establish an efficient system, there are two main things to do. The first one is to choose the right tools you need to accomplish the task in the best possible way. The second is to organize the space in which you will be doing the task.
Choose the Best Tools for the Task
Can you tell off the bat which tools you need the most to accomplish certain tasks? If you cannot, try remembering the following guidelines:
The tool should be the most user-friendly.
While this does not apply to all cases, it helps to remember to go back to the basics. Often, the tool that is easiest to use is also the more efficient. It does not require much time to learn how to use it and to manipulate it.
An example of a simple, user-friendly time management tool is the to Do list. It is simple as jotting down tasks on a piece of paper and crossing them out once you are done.
The tool should help you focus.
Some people who want to enhance their time management skills often tend to buy a number of “organizational tools,” such as planners, calendars, and so on, but then end up not using most of them at all. Worse, some would attempt to use them all at once and end up confused. Therefore, the best solution is to pick no more than one tool you will truly use for a particular project, goal, or task, and then stick to it.
The tool should be the most efficient and effective.
If a tool requires too much time to set up before you can use it, then it had better be four times more efficient than the other models. Otherwise, you would only end up accumulating wasted time from using it. The bottom-line is to choose a tool that will strike a balance between efficiency and effectiveness by looking at how well it can help you with the task and how quickly it can be used.
Aside from these, other factors you can consider are accessibility, cost, visibility, and so on, depending on the specific tools you need. After all, some tools are to be used for personal goals and tasks, while others are for professional use or team projects. Nevertheless, it helps to keep these three core guidelines in mind before you decide to choose a certain tool for your project.
Organize and Develop an Efficient Work Space
A space that is clean and organized does not just mean it is neat and tidy. Rather, it expands to keeping only the things you need in sight. Everything else that does not serve any purpose to your goal is merely a distraction. This rule applies not just to your physical surroundings, but your digital space as well.
You can achieve this by taking these simple steps:
Clear all the items off the area first. This will make it easier for you to separate the items and tools you want to use from the ones that only serve as distraction.
For instance, if your computer desktop is cluttered with all sorts of icons and folders, then create a folder and label it “Mess.” After that, move everything into it in one full sweep.
Re-build or re-organize the area by choosing the tools that you need. Everything else must be removed or stored away more efficiently.
If we go back to the same example, when you are left with a clear desktop, you can then choose from the “Mess” folder the ones you need for a particular project or goal. Everything else can be deleted or sorted out until you can safely delete the “Mess” folder.
Develop an efficient system for your project or goal.
Now that only the tools you need remain in the area, your final step is to use them to create an efficient system. It is important to ensure that the system is simple, easy to use, and effective, because you may be using it so often it becomes a habit.
Let us say you make a living as a medical transcriptionist. Since your desktop is now uncluttered, you now only have your transcribing tool, a spreadsheet icon of a file that helps you track your progress, and folder of projects on it. Your final step is to systematize how you work so that you can maximize your time and efficiency. It can be simple, such as:
Step 1: Click the spreadsheet icon to monitor and review project.
Step 2: Open transcribing tool.
Step 3: Open project to be transcribed.
Step 4: Put on headset, adjust volume, and start transcribing.
Once your tools and system are polished and organized, it is guaranteed that all the tasks you need to accomplish will become easier to do. All you need to do at this point is to take action.
A goal is a desired result or possible outcome that a person or a system envisions, plans and commits to achieve: a personal or organizational desired end-point in some sort of assumed development. Many people endeavor to reach goals within a finite time by setting deadlines.
It is roughly similar to purpose or aim, the anticipated result which guides reaction, or an end, which is an object, either a physical object or an abstract object, that has intrinsic value.
Setting the Goals
Goal setting may involve establishing specific, measurable, achievable, relevant, and time-bounded (SMART) objectives, but not all researchers agree that these SMART criteria are necessary.
Research on goal setting by Edwin A. Locke and his colleagues suggests that goal setting can serve as an effective tool for making progress when it ensures that group members have a clear awareness of what each person must do to achieve a shared objective. On a personal level, the process of setting goals allows individuals to specify and then work toward their own objectives (such as financial or career-based goals). Goal-setting comprises a major component of personal development and management.
Goals can be long-term, intermediate, or short-term. The primary difference is the time required to achieve them.
Short-term goals
Short-term goals expect accomplishment in a short period of time, such as trying to get a bill paid in the next few days. The definition of a short-term goal need not relate to any specific length of time. In other words, one may achieve (or fail to achieve) a short-term goal in a day, week, month, year, etc. The time-frame for a short-term goal relates to its context in the overall time line that it is being applied to. For instance, one could measure a short-term goal for a month-long project in days; whereas one might measure a short-term goal for someone’s lifetime in months or in years. Planners usually define short-term goals in relation to long-term goals.
In any endeavor, the first step is to establish a clear goal. The more detailed and clear it is, the easier it will be for you to make choices and establish steps that you need to take towards accomplishing it.
However, before getting into the subject of setting goals, let us first talk about the Goal-Setting Theory of Locke and Latham. Learning this will help you visualize the results that you truly want and need.
Dr. Edwin Locke, the author of the article “Toward a Theory of Task Motivation and Incentives”, published in 1968, explained that people become motivated towards doing their job when they are given clear goals as well as proper feedback. He also pointed that having a specific and challenging goal motivates people to boost their performance.
Twelve years later, Locke and Dr. Gary Latham published “A Theory of Goal Setting and Task Performance,” their seminal work. It not only highlighted the significance of setting definite and challenging goals, but also provided five key components that will guide you to set them successfully. These are Clarity, Challenge, Commitment, Feedback, and Task Complexity. Here are the steps on how you can use them:
Establish clear goals.
It is important to be detailed with what you want to accomplish. By doing so, you can track your progress and determine which areas you need to improve on and which ones are helping you to get closer to your goal.
Perhaps the most efficient way to establish goals is by applying the SMART criteria. This was first explained by George T. Doran in the November 1981 issue of Management Review. It has since become the primary tool used in setting goals.
“SMART” stands for Specific, Measurable, Achievable (or Assignable), Relevant, and Time-bound. Here is how you can apply each criterion:
Specific – the goal has to be so clear it leaves no room for doubt. Detail what is important to you, what you expect from it, how you will know when it happens, and so on.
Measurable – this puts emphasis on the need for measurable factors to help determine whether you are improving or not. Without measurable factors, you would find it impossible to stay motivated.
Assignable or Achievable – a goal may be specific and measurable, but it can be unachievable if it is unrealistic. It is important to ensure that you can either achieve the goal-related tasks yourself, or assign some of the tasks to someone who can.
Relevant – it is important to work towards a goal that is in line with your principles and purpose in life. For instance, you can consider whether the goal is worth the time, energy, and resources and if it is of true value to you.
Time-bound – a time frame is an essential part of goal setting, because it helps you commit and increases your focus. A goal that is not time-bound is usually shipped off to “someday” land and never seen again. Therefore, you must set a target date.
Here is an example of a SMART goal: “I will finish writing the first draft of my twenty-thousand-word romance fiction novel entitled “Oceans Away from Sarah” before December 25, 2016.”
Ensure that the goals are challenging
The more challenging yet realistic a goal is, the more motivated you will be to accomplish it. First, consider whether the goal you want makes you feel excited. Why does the thought of accomplishing it makes you feel good? Visualize the goal and determine the steps you need to take to turn it into a reality.
Commit yourself to the goal
Committing to your goal means that you are going to devote your time, energy, and resources to accomplish it. It also means you recognize its importance in your life and that you will not give up. It also helps to remember that plans can change, but the goal should remain the same.
Track your Progress to Get Feedback
As you work towards your goal, you must continuously enhance your skills, plans, and tools. That way, you can become even more efficient and effective. The only way to know how and what to improve on is by receiving feedback.
Feedback is easily given by a team leader and one’s peers in major projects, but if you are on your own, then you need to track your own progress to receive it. Therefore, you must create a way to measure your progress as soon as you start working towards your goal. Through these standards, you can determine how far along you are.
Calibrate the complexity of the task
If a certain task towards your goal is too challenging it becomes unrealistic, you can take a step back and make the necessary adjustments. In other words, do not charge head-on if you are unprepared for it, because you will only end up feeling too pressured. This is dangerous, because it can cause you to give up altogether.
Instead, consider the factors that are causing the task to be too complex. Reflect on whether you need more time, additional skills, or better tools for it. Maybe you need to break it down into smaller, more manageable parts. It is also possible that you need to delegate it to an expert. All these adjustments may even help you achieve your goal more efficiently.
Once you have established a clear goal, the next step is to generate tasks that are in line with it. By doing so, you would then be able to determine the time you need to accomplish it. How to Set Your Organize Priorities? posts will help you to identify which tasks are important each day, and which ones to set aside.
There are specific skills and steps that you can learn to effectively manage multiple priorities and to actually assess which activities you need to work on first then next in order to tame your daily and weekly schedule. I’ve tried to organize the best time management advice I can find into one place and make it “research administrator-friendly.”
The ability to prioritize is highly important in terms of achieving your goal. It helps you to identify and focus only on the essential tasks. It frees you from falling into procrastination or getting distracted by less important tasks. By harnessing this skill, you will be less stressed and a lot more organized and put-together.
To become proficient in prioritizing, you can start by applying former U.S. President Dwight D. Eisenhower’s Urgent/Important Principle.
Eisenhower’s Urgent/Important Principle
In 1954, he mentioned that there are “two kinds of problems: the urgent and the important. The urgent are not important, and the important are never urgent.” In this sense, these two concepts can be defined as follows:
Important tasks are those whose results lead to the achievement of our personal or professional goals.
Urgent tasks require your immediate attention. However, they are typically related to the goal of someone else (such as your boss). Nevertheless, we focus on them more because there are negative consequences to not doing them right away.
At this point, you may want to reflect on three things.
First, identify which tasks or activities are most important to you. Are they in line with your goal? How far along are you in terms of accomplishing it?
Second, look back on how you spend your time each day. Do you focus on what is urgent? Were you able to find time for what is important?
Finally, consider how you can make time for what is important and still be able to do what is urgent. Alternatively, think about whether you can sacrifice what is urgent for what is important.
One strategy that can help you focus on the important tasks first is to do them at the start of your day. The reason why this is effective is that you would still make time for what is urgent later on in the day. After all, you will always find a way to do what is urgent to avoid the consequence.
Make sure to write down all your thoughts until you can flesh out a concrete plan out of them.
The Pareto Principle
It is easy to prioritize when you are in control of your time and resources. However, things take a more challenging turn when you are faced with many issues that will force you to make quick decisions.
If ever you find yourself in this situation, then you can take a page out of Italian economist Wilfredo Pareto. According to him, eighty percent of the effects of most events come from twenty percent of the causes. To make his point clear, he explained two examples.
The first one is that 80 percent of the properties in his homeland are owned by only 20 percent of the population. The second, on which his principle is initially based, is that 20 percent of the pea-pods in his garden held 80 percent of the peas produce.
To this day, the Pareto Principle is being used by many professionals to gauge almost anything, such as by stating that 80 percent of a corporation’s sales come from only 20 percent of its products.
Going back to the concept of Prioritization, you can apply the Pareto Principle by applying the following steps:
Identify the main problems.
Take note of every issue that is holding you back from achieving your goal or task. If you are working as a team, consult each member to get their own insights. You might also need to consult your progress chart.
Determine the main cause of each problem.
According to the concept of Root Cause Analysis, there are three common root causes behind any problem. These are Physical Causes, Human Causes, and Organizational Causes.
When something breaks down or fails to operate due to some tangible or observable aspect, then it is due to a Physical Cause. One example is you being unable to finish a three-page report due tomorrow because your laptop computer crashed.
If a person failed to do something, or did something wrong, then the problem is from a Human Cause. An example would be your co-worker failing to send you an email of the survey results for your report tomorrow.
In situations where, despite the effectiveness of tools and the efficient skills of the people involved, the process itself caused the problem, then it is considered to be due to an Organizational Cause. One example is the pyramid scheme, in that the products are effective and the salespeople are passionate and trained. Yet, the system itself fails to be sustainable.
Based on this perspective, it is easy to identify the root cause of some problems. However, if you find it a challenge to do so, then you should ask yourself these questions to help you deduce the issue until you can identify the root cause.
What happened?
How did it happen?
Why did it happen?
Will it happen again?
Why or why not?
Rearrange the problems in order of priority.
After you have identified the root cause for each problem, you should then create another list of the same problems. Only this time, you will be enumerating them based on how important it is for them to be solved. This way, you will instantly know which one to focus on solving first before you move on to the second, third, and so on.
Come up with the solutions.
Now that you have analyzed and organized all the problems, the final step is to solve each of them. Start with the most important problem to be solved, and then brainstorm on the best steps to take to address it.
Now that you know how to apply Eisenhower’s Urgent/Important Principle and Pareto’s Principle, you can choose from a variety of time management tools in organizing all this information. A simple chart on a spreadsheet should do the trick, and it can look something like this:
Eisenhower’s Urgent/Important Principle
Today’s List of Tasks
Important Tasks Urgent Tasks
Task 1 – 8:00 am to 9:30 am Task 1 – 11:00 am to 12:00 am
Task 2 – 10:00 am to 10:30 am Task 2 – 1:00 pm to 3:00 pm
Pareto’s Principle
Ranking Problem Root Cause Solution:
1 Problem A Root Cause A Solution A
2 Problem B Root Cause B Solution B
3 Problem C Root Cause C Solution C
By using these tools, you will surely be able to get more tasks done throughout your day. Of course, this does not mean that these tools alone will enable you to focus on getting the job done. There will be times when we fail to focus on a task because of unexpected occurrences and distractions. However, you can overcome these challenges by improving your ability to concentrate. The next chapter can provide you with tips and strategies on how to do just that.
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.
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.
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.
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.
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.
Cells biology is the study of cell structure and function, and it revolves around the concept that the cell is the fundamental unit of life. Focusing on the cell permits a detailed understanding of the tissues and organisms that cells compose. Some organisms have only one cell, while others are organized into cooperative groups with huge numbers of cells. On the whole, cell biology focuses on the structure and function of a cell, from the most general properties shared by all cells, to the unique, highly intricate functions particular to specialized cells.
Cells Defined: One of the basic tenets of biology is that all living things are composed of one or more cells. Some organisms consist of a single cell, while others have multiple cells organized into tissues, and tissues organized into organs. In many living things, organs function together as an organ system. However, even in these complex organisms, the basic biology revolves around the activities of the cell.
The starting point for this discipline might be considered the 1830s. Though scientists had been using microscopes for centuries, they were not always sure what they were looking at. Robert Hooke’s initial observation in 1665 of plant-cell walls in slices of cork was followed shortly by Antonie van Leeuwenhoek’s first descriptions of live cells with visible moving parts. In the 1830s two scientists who were colleagues Schleiden, looking at plant cells, and Schwann, looking first at animal cells provided the first clearly stated definition of the cell. Their definition stated that all living creatures, both simple and complex, are made out of one or more cells, and the cell is the structural and functional unit of life a concept that became known as cell theory.
As microscopes and staining techniques improved over the nineteenth and twentieth centuries, scientists were able to see more and more internal detail within cells. The microscopes used by van Leeuwenhoek probably magnified specimens a few hundredfold. Today high-powered electron microscopes can magnify specimens more than a million times and can reveal the shapes of organelles at the scale of a micrometer and below. With confocal microscopy a series of images can be combined, allowing researchers to generate detailed three-dimensional representations of cells. These improved imaging techniques have helped us better understand the wonderful complexity of cells and the structures they form.
There are several main subfields within cell biology. One is the study of cell energy and the biochemical mechanisms that support cell metabolism. As cells are machines unto themselves, the focus on cell energy overlaps with the pursuit of questions of how energy first arose in original primordial cells, billions of years ago. Another subfield of cell biology concerns the genetics of the cell and its tight interconnection with the proteins controlling the release of genetic information from the nucleus to the cell cytoplasm. Yet another subfield focuses on the structure of cell components, known as subcellular compartments. Cutting across many biological disciplines is the additional subfield of cell biology, concerned with cell communication and signaling, concentrating on the messages that cells give to and receive from other cells and themselves. And finally, there is the subfield primarily concerned with the cell cycle, the rotation of phases beginning and ending with cell division and focused on different periods of growth and DNA replication. Many cell biologists dwell at the intersection of two or more of these subfields as our ability to analyze cells in more complex ways expands.
In line with the continually increasing interdisciplinary study, the recent emergence of systems biology has affected many biological disciplines; it is a methodology that encourages the analysis of living systems within the context of other systems. In the field of cell biology, systems biology has enabled the asking and answering of more complex questions, such as the interrelationships of gene regulatory networks, evolutionary relationships between genomes, and the interactions between intracellular signaling networks. Ultimately, the broader a lens we take on our discoveries in cell biology, the more likely we can decipher the complexities of all living systems, large and small.
One of the first scientists to observe cells was Englishman Robert Hooke. In the mid-1600s, Hooke examined a thin slice of cork through the newly developed microscope. The microscopic compartments in the cork impressed him and reminded him of rooms in a monastery, known as cells. He therefore referred to the units as cells. Later in that century, Anton Van Leeuwenhoek, a Dutch merchant, made further observations of plant, animal, and microorganism cells. In 1838, German botanist Matthias Schleiden proposed that all plants are composed of cells. A year later, his colleague, anatomist Theodor Schwann, concluded that all animals are also composed of cells. In 1858, biologist Rudolf Virchow proposed that all living things are made of cells and that all cells arise from preexisting cells. These premises have come down to us as the cell theory.
Movement Through the Plasma Membrane
In order for the cell cytoplasm to communicate with the external environment, materials must be able to move through the plasma membrane. This movement occurs through several mechanisms.
Diffusion: One method of movement through the membrane is diffusion. Diffusion is the movement of molecules from a region of higher concentration to one of lower concentration. This movement occurs because the molecules are constantly colliding with one another. The net movement of the molecules is away from the region of high concentration to the region of low concentration.
Diffusion is a random movement of molecules down the pathway called the concentration gradient. Molecules are said to move down the concentration gradient because they move from a region of higher concentration to a region of lower concentration. A drop of dye placed in a beaker of water illustrates diffusion as the dye molecules spread out and color the water.
Osmosis: Another method of movement across the membrane is osmosis. Osmosis is the movement of water from a region of higher concentration to one of lower concentration. Osmosis occurs across a membrane that is semipermeable. A semipermeable membrane lets only certain molecules pass through while keeping other molecules out. Osmosis is really a type of diffusion involving only water molecules.
Facilitated diffusion: A third mechanism for movement across the plasma membrane is facilitated diffusion. Certain proteins in the membrane assist facilitated diffusion by permitting only certain molecules to pass across the membrane. The proteins encourage movement in the direction that diffusion would normally take place, from a region with a higher concentration of molecules to a region of lower concentration.
Active transport: A fourth method for movement across the membrane is active transport. When active transport is taking place, a protein moves a certain material across the membrane from a region of lower concentration to a region of higher concentration. Because this movement is happening against the concentration gradient, the cell must expend energy that is usually derived from a substance called adenosine triphosphate, or ATP (see Chapter 4). An example of active transport occurs in human nerve cells. Here, sodium ions are constantly transported out of the cell into the external fluid bathing the cell, a region of high concentration of sodium. (This transport of sodium sets up the nerve cell for the impulse that will occur within it later.)
Endocytosis and exocytosis: The final mechanism for movement across the plasma membrane into the cell is endocytosis, a process in which a small patch of plasma membrane encloses particles or tiny volumes of fluid that are at or near the cell surface. The membrane enclosure then sinks into the cytoplasm and pinches off from the membrane, forming a vesicle that moves into the cytoplasm. When the vesicle contains solid particulate matter, the process is called phagocytosis. When the vesicle contains droplets of fluid, the process is called pinocytosis. Along with the other mechanisms for transport across the plasma membrane, endocytosis ensures that the internal cellular environment will be able to exchange materials with the external environment and that the cell will continue to thrive and function. Exocytosis is the reverse of endocytosis, where internally produced substances are enclosed in vesicles and fuse with the cell membrane, releasing the contents to the exterior of the cell.
The Structure of Prokaryote and Eukaryote Cells
During the 1950s, scientists developed the concept that all organisms may be classified as prokaryotes or eukaryotes. The cells of all prokaryotes and eukaryotes possess two basic features: a plasma membrane, also called a cell membrane, and cytoplasm. However, the cells of prokaryotes are simpler than those of eukaryotes. For example, prokaryotic cells lack a nucleus, while eukaryotic cells have a nucleus. Prokaryotic cells lack internal cellular bodies (organelles), while eukaryotic cells possess them. Examples of prokaryotes are bacteria and archaea. Examples of eukaryotes are protists, fungi, plants, and animals (everything except prokaryotes).
Plasma membrane: All prokaryote and eukaryote cells have plasma membranes. The plasma membrane (also known as the cell membrane) is the outermost cell surface, which separates the cell from the external environment. The plasma membrane is composed primarily of proteins and lipids, especially phospholipids. The lipids occur in two layers (a bilayer). Proteins embedded in the bilayer appear to float within the lipid, so the membrane is constantly in flux. The membrane is therefore referred to as a fluid mosaic structure. Within the fluid mosaic structure, proteins carry out most of the membrane’s functions.
The “Movement through the Plasma Membrane” section later in this chapter describes the process by which materials pass between the interior and exterior of a cell.
Cytoplasm and organelles: All prokaryote and eukaryote cells also have cytoplasm (or cytosol), a semiliquid substance that composes the volume of a cell. Essentially, cytoplasm is the gel-like material enclosed by the plasma membrane.
Within the cytoplasm of eukaryote cells are a number of membrane-bound bodies called organelles (“little organs”) that provide a specialized function within the cell.
One example of an organelle is the endoplasmic reticulum (ER). The ER is a series of membranes extending throughout the cytoplasm of eukaryotic cells. In some places, the ER is studded with submicroscopic bodies called ribosomes. This type of ER is called rough ER. In other places, there are no ribosomes. This type of ER is called smooth ER. The rough ER is the site of protein synthesis in a cell because it contains ribosomes; however, the smooth ER lacks ribosomes and is responsible for producing lipids. Within the ribosomes, amino acids are actually bound together to form proteins. Cisternae are spaces within the folds of the ER membranes.
Another organelle is the Golgi apparatus (also called Golgi body). The Golgi apparatus is a series of flattened sacs, usually curled at the edges. In the Golgi body, the cell’s proteins and lipids are processed and packaged before being sent to their final destination. To accomplish this function, the outermost sac of the Golgi body often bulges and breaks away to form drop like vesicles known as secretory vesicles.
An organelle called the lysosome (see Figure) is derived from the Golgi body. It is a drop like sac of enzymes in the cytoplasm. These enzymes are used for digestion within the cell. They break down particles of food taken into the cell and make the products available for use; they also help break down old cell organelles. Enzymes are also contained in a cytoplasmic body called the peroxisome.
Diagram of an Animal Cells Biology
Figure The components of an idealized eukaryotic cell. The diagram shows the relative sizes and locations of the cell parts.
The organelle that releases quantities of energy to form adenosine triphosphate (ATP) is the mitochondrion (the plural form is mitochondria). Because mitochondria are involved in energy release and storage, they are called the “powerhouses of the cells.”
Green plant cells, for example, contain organelles known as chloroplasts, which function in the process of photosynthesis. Within chloroplasts, energy from the sun is absorbed and transformed into the energy of carbohydrate molecules. Plant cells specialized for photosynthesis contain large numbers of chloroplasts, which are green because the chlorophyll pigments within the chloroplasts are green. Leaves of a plant contain numerous chloroplasts. Plant cells not specializing in photosynthesis (for example, root cells) are not green.
An organelle found in mature plant cells is a large, fluid-filled central vacuole. The vacuole may occupy more than 75 percent of the plant cell. In the vacuole, the plant stores nutrients, as well as toxic wastes. Pressure within the growing vacuole may cause the cell to swell.
The cytoskeleton is an interconnected system of fibers, threads, and interwoven molecules that give structure to the cell. The main components of the cytoskeleton are microtubules, microfilaments, and intermediate filaments. All are assembled from subunits of protein.
The centriole organelle is a cylinder like structure that occurs in pairs. Centrioles function in cell division.
Many cells have specialized cytoskeletal structures called flagella and cilia. Flagella are long, hair like organelles that extend from the cell, permitting it to move. In prokaryotic cells, such as bacteria, the flagella rotate like the propeller of a motorboat. In eukaryotic cells, such as certain protozoa and sperm cells, the flagella whip about and propel the cell. Cilia are shorter and more numerous than flagella. In moving cells, the cilia wave in unison and move the cell forward. Paramecium is a well-known ciliated protozoan. Cilia are also found on the surface of several types of cells, such as those that line the human respiratory tract.
Nucleus: Prokaryotic cells lack a nucleus; the word prokaryotic means “primitive nucleus.” Eukaryotic cells, on the other hand, have a distinct nucleus.
The nucleus of eukaryotic cells is composed primarily of protein and deoxyribonucleic acid, or DNA. The DNA is tightly wound around special proteins called histones; the mixture of DNA and histone proteins is called chromatin. The chromatin is folded even further into distinct threads called chromosomes. Functional segments of the chromosomes are referred to as genes. Approximately 21,000 genes are located in the nucleus of all human cells.
The nuclear envelope, an outer membrane, surrounds the nucleus of a eukaryotic cell. The nuclear envelope is a double membrane, consisting of two lipid layers (similar to the plasma membrane). Pores in the nuclear envelope allow the internal nuclear environment to communicate with the external nuclear environment.
Within the nucleus are two or more dense organelles referred to as nucleoli (the singular form is nucleolus). In nucleoli, submicroscopic particles known as ribosomes are assembled before their passage out of the nucleus into the cytoplasm.
Although prokaryotic cells have no nucleus, they do have DNA. The DNA exists freely in the cytoplasm as a closed loop. It has no protein to support it and no membrane covering it. A bacterium typically has a single looped chromosome.
Cell Wall
Many kinds of prokaryotes and eukaryotes contain a structure outside the cell membrane called the cell wall. With only a few exceptions, all prokaryotes have thick, rigid cell walls that give them their shape. Among the eukaryotes, some protists, and all fungi and plants, have cell walls. Cell walls are not identical in these organisms, however. In fungi, the cell wall contains a polysaccharide called chitin. Plant cells, in contrast, have no chitin; their cell walls are composed exclusively of the polysaccharide cellulose.
Cell walls provide support and help cells resist mechanical pressures, but they are not solid, so materials are able to pass through rather easily. Cell walls are not selective devices, as plasma membranes are.
The cell (from Latin cella, meaning “small room”) is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, and cells are often called the “building blocks of life”. The study of cells is called cell biology.
Cells consist of cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Organisms can be classified as unicellular (consisting of a single cell; including bacteria) or multicellular (including plants and animals). While the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion (1012) cell. Most plant and animal cells are visible only under a microscope, with dimensions between 1 and 100 micrometers.
The cell was discovered by Robert Hooke in 1665, who named the biological unit for its resemblance to cell inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cell, that cell are the fundamental unit of structure and function in all living organisms, that all cell come from preexisting cell, and that all cell contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. Cells emerged on Earth at least 3.5 billion years ago.
Types of Cells
Eukaryote and Prokaryote
Prokaryote Cells
Prokaryotic cells were the first form of life on Earth, characterized by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells and lack membrane-bound organelles such as the nucleus. Prokaryotes include two of the domains of life, bacteria, and archaea. The DNA of a prokaryotic cell consists of a single chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid. Most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter.
A prokaryotic cell has three architectural regions:
I. Enclosing the cell is the cell envelope generally consisting of a plasma membrane covered by a cell wall which, for some bacteria, may be further covered by a third layer called a capsule. Though most prokaryotes have both a cell membrane and a cell wall, there are exceptions such as Mycoplasma (bacteria) and Thermo-plasma (archaea) which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, serving as a protective filter. The cell wall consists of peptidoglycan in bacteria and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting (cytolysis) from osmotic pressure due to a hypotonic environment. Some eukaryotic cells (plant cells and fungal cells) also have a cell wall.
II. Inside the cell is the cytoplasmic region that contains the genome (DNA), ribosomes and various sorts of inclusions. The genetic material is freely found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular. Linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid. Plasmids encode additional genes, such as antibiotic resistance genes.
III. On the outside, flagella and pili project from the cell’s surface. These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells.
The Structure of Prokaryote and Eukaryote Cells
Eukaryote Cells
Plants, animals, fungi, slime moulds, protozoa, and algae are all eukaryotic. These cells are about fifteen times wider than a typical prokaryote and can be as much as a thousand times greater in volume. The main distinguishing feature of eukaryotes as compared to prokaryotes is compartmentalization: the presence of membrane-bound organelles (compartments) in which specific metabolic activities take place. Most important among these is a cell nucleus, an organelle that houses the cell’s DNA. This nucleus gives the eukaryote its name, which means “true kernel (nucleus)”. Other differences include:
I. The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may or may not be present.
II. The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria also contain some DNA.
III. Many eukaryotic cell are ciliated with primary cilia. Primary cilia play important roles in chemosensation, mechanosensation, and thermosensation. Cilia may thus be “viewed as a sensory cellular antenna that coordinates a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation.”
IV. Motile cells of eukaryotes can move using motile cilia or flagella. Motile cells are absent in conifers and flowering plants. Eukaryotic flagella are less complex than those of prokaryotes.
