Week 2 - Major Molecules: Engage/Explore

• Due Sunday by 11:59pm
• Points 1
• Submitting a text entry box

As we saw in the video on Alzheimer's disease that we reviewed earlier, there are a variety of specific molecules, besides just water, that we care about in relation to health and disease.  One of the main molecules in that video was beta amyloid, a protein.  Proteins, along with lipids, nucleic acids, and carbohydrates, will represent some of the most critical molecules for us in anatomy and physiology.  Those four types of molecules should become your good friends in this course!

In the coming pages and activities, we will review your understanding of those molecules and ensure the entire class has a common understanding of those chemicals. For now, consider the statement in quotation marks below.

“You can find proteins in your brain, carbs in your muscles, and fats in your bones.”

Do you agree or disagree with the statement above?  Why or why not? 

(Please state your opinion and write at least 2 sentences to explain. Your responses are scored only for providing a response, not for being "right" or "wrong."  This is simply a chance to explore your existing ideas.)

Properties of Water

Week 2 - Chemistry: Elaborate/Evaluate

  Correct answers are hidden.

Score for this attempt: 5 out of 5

Submitted Jan 20 at 9:02pm

This attempt took 6 minutes.

 

Question 1

1 / 1 pts

Which of the atoms below is the smallest in size?

 

Hydrogen

 

Carbon

 

Oxygen

 

Nitrogen

 

Question 2

1 / 1 pts

Which type of bond is formed when atoms share electrons?

 

Covalent Bond

 

Hydrogen Bond

 

Ionic Bond

 

Weak Bond

 

Question 3

1 / 1 pts

Which type of bond involves relatively weak attractions between slightly negative and slightly positive atoms or molecules?

 

Ionic Bond

 

Covalent Bond

 

Metallic Bond

 

Hydrogen Bond

 

Question 4

1 / 1 pts

What type of bond is shown above using a dotted line (indicated by the blue arrow)?

 

Metallic Bond

 

Hydrogen Bond

 

Ionic Bond

 

Covalent Bond

 

Question 5

1 / 1 pts

Which types of chemical bonds are shown in the diagram of a protein molecule above?

 

Ionic Bonds Only

 

Covalent Bonds Only

 

Covalent Bonds & Ionic Bonds

 

Ionic Bonds & Hydrogen Bonds

 

Covalent Bonds & Hydrogen Bonds

Quiz Score: 5 out of 5

Properties of Water

 

Week 2 - Chemistry: Explain

Clarifying Atoms, Elements, and Molecules

As you saw in the last activity for this module, Bio 40A students have a wide range of ideas of what water looks like!  While there are certainly many different "correct" ways to draw water, we would like to narrow down our ideas and be able to create scientifically supported diagrams.  Perhaps we can begin by agreeing that each water molecule is composed of atoms.  Click here

Links to an external site. to review the "Elements and Atoms" section of our book.  As you read, be sure to clarify your thoughts regarding following questions related to water (and eventually related to the other topics we will study!).

• What exactly is an atom vs. an element vs. a molecule?
• What types of atoms, and how many of each, make up water?
• Which of those atoms are bigger vs. smaller, and why?
• Why do the atoms in a water molecule interact and partner with one another?

Homeostasis

 Homeostasis depends on the ability of your body to detect and oppose these changes.

Maintenance of homeostasis usually involves negative feedback loops. These loops act to oppose the stimulus, or cue, that triggers them.

Is temperature a positive or negative feedback loop?

If the temperature is high, the body sweats in order to cool down. Since the process of sweating is done to stop the temperature change, this is a negative feedback. Feedback loops come in two flavors: positive and negative. A negative feedback loop reduces the effect of change and helps maintain balance.

chegg response

 In a positive feedback loop, the response amplifies the initial stimulus, leading to a further increase in the stimulus. In the case of a fever, the elevated body temperature triggers the release of chemicals called pyrogens, which signal the hypothalamus in the brain to raise the body’s set point for temperature. This causes the body to generate and retain more heat, leading to a further increase in body temperature 12.

The human body has a complex mechanism to maintain homeostasis, which is the tendency to resist change in order to maintain a stable, relatively constant internal environment 1. Homeostasis typically involves negative feedback loops that counteract changes of various properties from their target values, known as set points. In contrast to negative feedback loops, positive feedback loops amplify their initiating stimuli, in other words, they move the system away from its starting state 1.

Positive feedback loops are not always harmful. For instance, during childbirth, the hormone oxytocin is released, which stimulates uterine contractions. These contractions push the baby towards the birth canal, leading to more oxytocin release and stronger contractions, until the baby is born 2.

I hope this helps!

 Higher temperature indicates that primarily in response to an infection. Maintaining high temperature 

Week 2 - Considering another feedback loop

 

This is a graded discussion: 1 point possible
due Jan 21
Week 2 - Considering another feedback loop
18
18 unread replies.
31
31 replies.

group-discussion.jpgLet's examine another scenario and see if we can uncover what sort of feedback loop is in play here.  Note that this will be a very common and relatable scenario, but it's one that students in the past have found quite tricky in terms of its feedback loop characteristics!

Consider the prompt below and compose a post with your response.  You will receive 1 point for submitting a post of your own (3 sentences or more), after which you will be able to see your colleagues' posts.

 

Discussion Prompt:

Fever is one of the most common symptoms of coronavirus.  Most of you have likely had fevers before!  For example, during a fever, your body might maintain a high temperature (e.g., 101°F) for a few days.

During a fever, when your body is maintaining 101°F, is your body temperature in a negative or positive feedback loop?  How can you tell?
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    Mariah Loya
    Mariah Loya
    Tuesday
    Jan 16 at 5:24pm

    I believe your body is in a positive feedback loop. I say this because we are starting with a fever and ending with a fever. if it was a negative feedback loop, then we would end with no fever.
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    Cordell Reed
    Cordell Reed
    Tuesday
    Jan 16 at 6:09pm

    it is a positive feed back because its self reinforcing mechanisms the initial signal.which makes it a posotive feed back due to the facts that it is doing more and amplifying the body temperature.
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    Richard Joseph
    Richard Joseph
    Tuesday
    Jan 16 at 7pm

    Your body would be in a negative feedback loop because you’re not getting any better. The only way it would be considered a positive feedback loop would be if you got better. Also your body could potentially be a positive feedback loop if you’re body was trying to fight the illness.
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    Jorge Sosa Castellanos
    Jorge Sosa Castellanos
    Tuesday
    Jan 16 at 7:27pm

    The body is in a positive feedback loop in this scenario. This is because when sick, in this case, the body temperature rises but doesn't seem to drop back down to a regular temperature. If the body were in a negative feedback loop, the body temperature would drop back to homeostasis.
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    Hazel Mendoza
    Hazel Mendoza
    Tuesday
    Jan 16 at 8:30pm

    I think this fever is an example of a negative feedback loop. Since the body is maintaining a high temperature, it stays close to/at the set point. The body keeps the temperature close to the set point making it a negative feedback loop.
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    Jasmin Villicana-Lopez
    Jasmin Villicana-Lopez
    Tuesday
    Jan 16 at 9pm

    I believe it is Negative feedback because normally your body temperature is not high but during a fever your temperature rises. I use the arrow method and got negative feedback. I believe the question can get interpreted differently if you have the fever and the temperature stays the same it would be positive feedback.
    Edited by Jasmin Villicana-Lopez on Jan 16 at 9:04pm
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    Melissa Escobar
    Melissa Escobar
    Tuesday
    Jan 16 at 10:04pm
    I would say the body is in a positive feedback loop considering the body is maintaining a high temperature rather than reducing. During a negative feedback loop, the body would be regulating body temp back to normal. However in this case, it’s displaying a temperature that is above normal.
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    Angelica Galdamez Gutierrez
    Angelica Galdamez Gutierrez
    Tuesday
    Jan 16 at 11:50pm

    When your body is maintaining a 101 degrees fever, your body temperature is in a positive feedback loop. I believe it's in a positive feedback loop because I noticed that the example used the word "maintaining" which means that the fever is not getting any better. Instead the body continues to remain at a high temperature for several days. Though the body may be working to fight against the fever, in this example no changes opposite to the deviation seem to be resulting which is why I wouldn't label this a negative feedback loop.  
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    Tonya Cedillo
    Tonya Cedillo
    Wednesday
    Jan 17 at 7:31am

    I think the body is in a positive loop. The stimulus is a high temperature. The fact that the body temperature is staying the same or maintaining denotes a positive loop feedback.
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    Justin Laster
    Justin Laster
    Wednesday
    Jan 17 at 9:17am

    I believe that the this example is a negative feedback loop. I think the body is just creating a new set point for the body temperature as it fights off the virus. Since your body maintains 101 degrees then your body is going against the deviation to lower. the body temperature.
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    Briana McDowell
    Briana McDowell
    Wednesday
    Jan 17 at 10:01am

    I think that during a fever, when your body is maintaining 101 degrees that your body temperature is in a negative feedback loop. This is because in a positive feedback loop, the body is increasing its temperature. However, the negative feedback loop is maintaining the body's temperature at 101. This is because in a negative feedback loop the result of a reaction is reduced to bring the system back to a stable state. In general, if a fever reaches 103-105, it is considered to be dangerous, but since the body can keep the fever at a safe level and still be high enough for it to fight off any infections is it being maintained.
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    Sean Sok
    Sean Sok (He/Him)
    Wednesday
    Jan 17 at 4:46pm

    I think that this is a positive feedback loop because if it is initially a high temperature and has not decreased, then the temperature is just being amplified.
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    Marsela Arreola Garcia
    Marsela Arreola Garcia
    Wednesday
    Jan 17 at 5:13pm

    this is an example of a positive feedback loop because when your body detects an infection it increases your bodies temp.
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    Angela Avalos
    Angela Avalos
    Wednesday
    Jan 17 at 8:37pm

    During a fever you're body temperature Is in a positive feedback loop. It's positive feedback because its not going the opposite direction to a lower body temperature which would make it a negative feedback . Maintaining a high fever is going the same direction as the deviation .
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    Michael Molcsan
    Michael Molcsan
    Wednesday
    Jan 17 at 9:42pm

    I believe that an increased body temperature from a fever is an example of a negative feedback loop. I think this because the increased temperature is a reaction from the body trying fight an infection. The way I went about this thought process is similar to what we did in class with the up and down arrow. The body senses an "increase" in infection and ups the body temperature to "decrease" the infection. Once the infection is gone you will typically break the fever and your body temperature will go back to normal.
    Edited by Michael Molcsan on Jan 17 at 9:43pm
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    Kalena Cao
    Kalena Cao
    Wednesday
    Jan 17 at 10:27pm

    During a fever when your body is maintaining 101°F; your body temperature is in a positive feedback loop as it is maintaining 101°F rather than going back to the set point when the body is trying to reduce the fever. The average body temperature is 98.6°F and the fever rises to 101°F while also maintaining at that temperature. For it to be considered as a negative feedback loop, the body temperature must decrease to the set point. However, that is not the case with the body continues to stay at 101°F, which makes it a positive feedback loop as it does not go back to the set point.
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    Michael Terrell Jr
    Michael Terrell Jr
    Thursday
    Jan 18 at 12:21pm

    A fever of 101 degrees for a few days is considered a negative feedback loop. This is your bodies way of fighting off the pathogen in order to get your body back into homeostasis. You can tell because your cell receptors detect a pathogen has entered the body and a fever acts as the effector. Generally speaking fever's at 101 degrees isn't necessarily a bad thing, this is why medical professionals will typically tell you to stay home and rest. Some also believe that our white bloods cells work better in the raised body temperature.

     

    Now, if the fever never went back down to the normal set point after a few days or if the fever increased then this would be an example of positive feedback loop.
    Edited by Michael Terrell Jr on Jan 18 at 12:31pm
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    Thomas Raffa
    Thomas Raffa
    Thursday
    Jan 18 at 3:49pm

    This is a negative feedback loop because it is at an equilibrium point. If you take a fever-reducing medication, the fever will return after the drug wears off because your body is actively maintaining that temperature. Therefore, this is an example of negative feedback.
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    Diana Hernandez Barba
    Diana Hernandez Barba (She/Her)
    Thursday
    Jan 18 at 5:40pm

    When having a fever of 101°F for a few days I would say this is a positive feedback loop. This is a positive feedback loop because the fever is being maintaining at that temperature but it isn't going back to the original set point. Positive feedback is known for things to be moved further away from the set point like staying above, below or the same but away from the set point.
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    Kevin Pham
    Kevin Pham
    Thursday
    Jan 18 at 6:20pm

    During a fever, when our body is maintaining 101°F, our body temperature is in a negative feedback loop. This is because the temperature control is a negative feedback mechanism that it is to help fight off an infection or the fever itself to which the body heat is lost to environment then it drops down to normal body temperature.
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    Minhthy-Jacqlyn Le
    Minhthy-Jacqlyn Le
    Thursday
    Jan 18 at 7:18pm

    During a fever, when your body is maintaining 101°F fever your body would be in a negative feedback loop. You can tell it's in an negative feedback loop because the body's initial stimulus is a 101°F fever and if the response is still at a 101°F fever, there was no counteracting response to the initial stimulus. Thus, since they are the same it is still considered a negative feedback loop, even if the fever temperature isn't decreasing.
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    Elex Felix
    Elex Felix
    Thursday
    Jan 18 at 7:22pm

    I believe the body temperature is in a negative feedback loop. I can tell because the body is maintaining a high temperature rather than letting the temperature exceed normal limits. Although a temperature of 101°F+ is not normal, the body is fighting off the infection and not allowing it to become worse therefore maintaining stability.
    Edited by Elex Felix on Jan 18 at 7:29pm
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    Natalie Mahjoor
    Natalie Mahjoor
    Thursday
    Jan 18 at 9:29pm

    It is typically in a positive feedback loop. In a positive feedback loop, the response reinforces and amplifies the stimulus, leading to an increase in the original disturbance. In the case of a fever, the elevated body temperature is the stimulus. As the body detects an infection or other factors triggering the fever, it initiates a response to increase the body temperature. The higher temperature creates an environment less favorable for the growth of certain pathogens, contributing to the body's defense mechanisms. The positive feedback loop continues until the body successfully fights off the infection or the external factors causing the fever. Once the trigger is resolved, the body returns to its normal temperature through various mechanisms, such as sweating and increased blood flow to dissipate heat.
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    Vincent Lal
    Vincent Lal
    Thursday
    Jan 18 at 9:36pm
    During a fever, I believe for our body to maintain 101 °F is in a positive feedback loop. That is because it is a deviation from normal range to a definite end point. And that is because the high temperature is a response that your body is fighting off the virus.
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    Kyaw Latt
    Kyaw Latt
    Yesterday
    Jan 19 at 1:22am

    In my opinion, the body temperature is in a positive feedback loop because fever increases body temperature to 101 'F. The body's defense mechanism can not maintain to normal body temperature at 98.6'F. That result shows the direct proportion of fever and higher body temperature .
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    Kathleen Kaye Celis
    Kathleen Kaye Celis
    Yesterday
    Jan 19 at 2:52pm

    During our lecture class, we did group work on the Coronavirus feedback loop. We also understood that macrophages, which operate as receptors and control centers, and T-cells, which act as effectors, collaborate to keep the body in homeostasis. When our body comes into contact with a virus, specifically Coronavirus, it responds by raising its temperature. We  have a fever because our body is attempting to eliminate the virus or bacteria that caused the infection. Most of these bacteria and viruses thrive when our body temperature is normal. However, having a fever makes it tougher for them to live.Therefore, Fever is an example of a negative feedback loop.
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    Tianna Tran
    Tianna Tran
    Yesterday
    Jan 19 at 7:22pm

    During a fever, my body temperature is in a positive feedback loop, which means it's increasing to fight an infection. The elevated temperature triggers more responses to boost the fight against the infection. It's like my body's way of turning up the heat to help get rid of the intruders.
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    Lizette Romero Martinez
    Lizette Romero Martinez
    Yesterday
    Jan 19 at 9:05pm

    This situation shows a negative feedback loop. The reason for that is because during covid, if you were to get a fever, it will maintain at a high temperature for a few days. After those few days have passed, then it will go down to a normal temperature. You start off with a high temperature and end with a normal temperature.
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    Jocelyn Perez Diaz
    Jocelyn Perez Diaz
    Yesterday
    Jan 19 at 9:14pm

    During a fever when a bosy is maintaing itself at 101 degrees F, the body is in a positive feedback loop. The definition of a Positive feedback loop is when the body deviates further from the set point which in this case is normal body tempt of 96 to 98. The body is pushing the effectors extra hard to bring the body back to it's regular set point.  
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    Shariany Moreno
    Shariany Moreno (She/Her)
    Yesterday
    Jan 19 at 10:38pm

    In this example, I believe the body temperature is a negative feedback loop. Since the example says the body is maintaining a temperature of 101°F, that may mean that 101°F is the set point in this case. The body will try to reverse that change to go back to normal levels.
    Edited by Shariany Moreno on Jan 19 at 10:49pm
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    Phyu Phyu Thant
    Phyu Phyu Thant
    5:53am
    Jan 20 at 5:53am

    when someone was contracted corona virus the patient presented symptom that having fever high temperature. When the temperature elevated releasing chemical signal reported to the brain causing the body to generate more heat. In my point of view elevated body temperature is called negative loop.
    Edited by Phyu Phyu Thant on Jan 20 at 5:55am
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What is the negative feedback mechanism in the regulation of body temperature?

 What is the negative feedback mechanism in the regulation of body temperature?

1 Answer

Henry W.

Oct 2, 2016

Thermoregulation

Explanation:

Thermoregulation refers to the regulation of body temperature. Changes in temperature can either be external or internal. We have receptors on our skin (peripheral receptors) for external changes, and receptors in our brain (central receptors) which monitor the temperature of blood as it circulates through the brain.

Now, when the stimulus of a change in temperature is detected by your receptors, it sends a message to the hypothalamus, the control centre responsible for thermoregulation. The anterior hypothalamus is responsible for cooling the body down, whereas the posterior hypothalamus is responsible for heating the body up. A message from the receptors is interpreted by the hypothalamus, then sent to the appropriate effectors.

When temperatures get too high, effectors include sweat glands and muscle tissue in arterioles (blood vessel). The anterior hypothalamus tells sweat glands to secrete sweat, which cool the body down by evaporative cooling. Furthermore, arterioles are dilated in order to increase blood flow to the skin, resulting in the loss of heat (this is called vasodilation).

When temperatures get too low, effectors include erector muscles in your skin and muscle tissue in arterioles. The posterior hypothalamus tells ur erector muscles to contract, giving you goosebumps and raises hairs. This reduces heat loss and basically "traps" a layer of warm heat above your skin. Furthermore, arterioles are told to constrict, decreasing blood flow to the skin, resulting in the retention of heat (vasoconstriction).

week 2 - Considering another feedback loop

 

3030 unread replies.3030 replies.

Let's examine another scenario and see if we can uncover what sort of feedback loop is in play here.  Note that this will be a very common and relatable scenario, but it's one that students in the past have found quite tricky in terms of its feedback loop characteristics!

Consider the prompt below and compose a post with your response.  You will receive 1 point for submitting a post of your own (3 sentences or more), after which you will be able to see your colleagues' posts. 

 

Discussion Prompt:

Fever is one of the most common symptoms of coronavirus.  Most of you have likely had fevers before!  For example, during a fever, your body might maintain a high temperature (e.g., 101°F) for a few days.

During a fever, when your body is maintaining 101°F, is your body temperature in a negative or positive feedback loop?  How can you tell?

here’s the best way to solve it.

Powered by Chegg AI

During a fever, when your body is maintaining a temperature of 101°F, your body temperature is in a positive feedback loop.

Explanation:

In a positive feedback loop, the response amplifies the initial stimulus, leading to a further increase in the stimulus. In the case of a fever, the elevated body temperature triggers the release of chemicals called pyrogens, which signal the hypothalamus in the brain to raise the body's set point for temperature. This causes the body to generate and retain more heat, leading to a further increase in body temperature.

Options:

Negative feedback loop: This is incorrect because a negative feedback loop would work to counteract the initial stimulus and bring the body temperature back to normal. During a fever, the body is actively maintaining a higher temperature, not trying to bring it down.

Positive feedback loop: This is the correct answer. As explained above, during a fever, the body temperature is maintained in a positive feedback loop where the elevated temperature leads to further increases in body temperature.

No feedback loop: This is incorrect because the body's response to a fever involves a feedback loop. The release of pyrogens and the subsequent increase in body temperature are part of a feedback mechanism.

Both negative and positive feedback loops: This is incorrect because during a fever, the body temperature is specifically maintained in a positive feedback loop. There is no involvement of a negative feedback loop in this scenario.

Cytoskeleton

The Cytoskeleton

Much like the bony skeleton structurally supports the human body, the cytoskeleton helps the cells to maintain their structural integrity. The cytoskeleton is a group of fibrous proteins that provide structural support for cells, but this is only one of the functions of the cytoskeleton. Cytoskeletal components are also critical for cell motility, cell reproduction, and transportation of substances within the cell.

The cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein-based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3.18). The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Microtubules also make up two types of cellular appendages important for motion: cilia and flagella. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells.

Figure 3.18 The Three Components of the Cytoskeleton The cytoskeleton consists of (a) microtubules, (b) microfilaments, and (c) intermediate filaments. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division.

A very important function of microtubules is to set the paths (somewhat like railroad tracks) along which the genetic material can be pulled (a process requiring ATP) during cell division, so that each new daughter cell receives the appropriate set of chromosomes. Two short, identical microtubule structures called centrioles are found near the nucleus of cells. A centriole can serve as the cellular origin point for microtubules extending outward as cilia or flagella or can assist with the separation of DNA during cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain.

In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3.18b). Actin, a protein that forms chains, is the primary component of these microfilaments. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. Like microtubules, actin filaments are long chains of single subunits (called actin subunits). In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell.

Actin also has an important role during cell division. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell.

The final cytoskeletal filament is the intermediate filament. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3.18c). Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions.

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 Cell: The Free Radical Theory

The free radical theory on aging was originally proposed in the 1950s, and still remains under debate. Generally speaking, the free radical theory of aging suggests that accumulated cellular damage from oxidative stress contributes to the physiological and anatomical effects of aging. There are two significantly different versions of this theory: one states that the aging process itself is a result of oxidative damage, and the other states that oxidative damage causes age-related disease and disorders. The latter version of the theory is more widely accepted than the former. However, many lines of evidence suggest that oxidative damage does contribute to the aging process. Research has shown that reducing oxidative damage can result in a longer lifespan in certain organisms such as yeast, worms, and fruit flies. 

Conversely, increasing oxidative damage can shorten the lifespan of mice and worms. 

Interestingly, a manipulation called calorie-restriction (moderately restricting the caloric intake) has been shown to increase life span in some laboratory animals. It is believed that this increase is at least in part due to a reduction of oxidative stress. However, a long-term study of primates with calorie-restriction showed no increase in their lifespan. A great deal of additional research will be required to better understand the link between reactive oxygen species and aging.

Reactive oxygen species (ROS)

 Reactive oxygen species (ROS) such as peroxides and free radicals are the highly reactive products of many normal cellular processes, including the mitochondrial reactions that produce ATP and oxygen metabolism. Examples of ROS include the hydroxyl radical OH, H2O2, and superoxide (

O−2${\text{O}}_2^{-}$). Some ROS are important for certain cellular functions, such as cell signaling processes and immune responses against foreign substances. Free radicals are reactive because they contain free unpaired electrons; they can easily oxidize other molecules throughout the cell, causing cellular damage and even cell death. Free radicals are thought to play a role in many destructive processes in the body, from cancer to coronary artery disease.

Peroxisomes, on the other hand, oversee reactions that neutralize free radicals. Peroxisomes produce large amounts of the toxic H2O2 in the process, but peroxisomes contain enzymes that convert H2O2 into water and oxygen. 

These byproducts are safely released into the cytoplasm.

 Like miniature sewage treatment plants, peroxisomes neutralize harmful toxins so that they do not wreak havoc in the cells.

 The liver is the organ primarily responsible for detoxifying the blood before it travels throughout the body, and liver cells contain an exceptionally high number of peroxisomes.

Defense mechanisms such as detoxification within the peroxisome and certain cellular antioxidants serve to neutralize many of these molecules. 

Some vitamins and other substances, found primarily in fruits and vegetables, have antioxidant properties.

 Antioxidants work by being oxidized themselves, halting the destructive reaction cascades initiated by the free radicals. Sometimes though, ROS accumulate beyond the capacity of such defenses.

Oxidative stress is the term used to describe damage to cellular components caused by ROS.

 Due to their characteristic unpaired electrons, ROS can set off chain reactions where they remove electrons from other molecules, which then become oxidized and reactive, and do the same to other molecules, causing a chain reaction. 

ROS can cause permanent damage to cellular lipids, proteins, carbohydrates, and nucleic acids. 

Damaged DNA can lead to genetic mutations and even cancer. 

A mutation is a change in the nucleotide sequence in a gene within a cell’s DNA, potentially altering the protein coded by that gene.

Other diseases believed to be triggered or exacerbated by ROS include Alzheimer’s disease, cardiovascular diseases, diabetes, Parkinson’s disease, arthritis, Huntington’s disease, and schizophrenia, among many others. It is noteworthy that these diseases are largely age-related. Many scientists believe that oxidative stress is a major contributor to the aging process.