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2 Feb 2018

1. Circle all that are true. Polymerization and depolymerization of actin are essential for:

A. production of contractile forces in cells (ex. muscle cells)

B. movement of cilia and flagella

C. crawling movements of cells over surfaces

D. maintaining the shape of a red blood cell

2. What would happen to treadmilling of actin if you add phalloidin to a cell? Explain your answer.

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28 Jul 2023

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Related questions

1. Kinesin-1 motors can move long distances on microtubule tracks without dissociating. By contrast, myosin II motors in skeletal muscle take only one or a few steps before letting go. What is most likely the difference between these two motors that allow two different types of movement?

A. Differences in length of the stalk of each respective motor allow for differences in step size

B. Differences in ATP versus GTP hydrolysis alter the motor head movement along filaments

C. Actin filaments are smaller in diameter and have less space for movement

D. Binding affinity of the Kinesin-1 motor head to microtubules is high, whereas binding affinity of the myosin II motor head to actin filaments is low

E. Microtubules are larger in diameter and have more space for movement

2. Dynamic instability causes microtubules either to grow or to shrink rapidly. What is the most likely reason for a microtubule to undergo rapid growth?

A. GTP hydrolysis exceeds the rate of heterodimer addition

B. GTP hydrolysis of alpha tubulin causes an outward bend in the heterodimer conformation

C. A low concentration of tubulin heterodimers are in solution

D. Heterodimer addition exceeds the rate of GTP hydrolysis

E. Increased trafficking of microtubule motor proteins favors stability

3. There are no known motor proteins that move on intermediate filaments (IFs). What property of intermediate filaments would most likely explain the lack of motor proteins?

A. Tissue specific expression of IFs prevent a single type of motor protein to evolve over time

B. Lateral bundling of IFs prevent motor movement

C. IFs are less dynamic than microtubules and actin filaments

D. IFs are unpolarized

E. IFs do not bind a nucleotide

4. You discover a mutation that results in less rapid hydrolysis of GTP by the beta-tubulin subunit. What would most likely occur?

A. There would be no change in filament assembly

B. There would be enhanced instability of the microtubule

C. There would be enhanced stability of the microtubule

D. Microtubules would not form

E. There would be enhanced treadmilling

5. Which of the following statements describes common features of cadherins and integrins?

A. They can link to microtubules using specific adapter proteins

B. They mediate heterophillic interactions

C. They achieve high binding affinity through clustering

D. They are responsible for interactions of a cell with the extracellular matrix

E. They are found in the apical plasma membrane of an epithelial cell

6. Intermediate filaments are uniquely non-polar and built by lateral bundling in five steps: 1) synthesis of an alpha-helical monomer, 2) formation of a coiled-coil dimer, 3) formation of a staggered tetramer of two coiled-coil dimers, 4) lateral association of 8 tetramers, and 5) addition of 8 tetramers to a growing filament. At what step is polarity lost?

A. Step 1

B. Step 2

C. Step 3

D. Step 4

E. Step 5

7. Collagenase is an enzyme that breaks peptide bonds in collagen to help destroy extracellular structures. What would be the most likely reason to use collagenase in a cell biology laboratory?

A. Disrupt cadherin interaction with the extracellular matrix

B. Disrupt cell-cell contacts to passage cells in cell culture

C. Dissociate epithelial cells from the underlying basement membrane to separate tissues

D. All of the answers are likely uses for collagenase

E. Lyse cells to expose intracellular proteins and organelles

yellowherring775

i need help with this homwork please choose the correct answers and just be claer to read and understand for the slect the apply qusestions too and it is important i realy need the right answers so please be claer not write randomly i really need the correct answers to study for my test so hop you can help me

Question 1

What is the smallest cell you could find?

Question 2

TEMs appear as 3D images

True

False

Question 3

Bacteria are what cell type? Write one word as the answer in lowercase and using no syntax.

Flag this Question

Question 42 pts

ALL eukaryotic cells have which of the following. Click all that apply.

membrane enclosed cell organelles

mitochondria

Question 5

Prokaryotes and eukaryotes both have which if the following cellular components. Click all that apply.

Question 6

I am made of one 60s and one 40s subunit, which organelle am I?

protein

lipid

bacterial ribosome

Question 9

The difference between the rough and smooth ER is

the rough produces lipids where as the smooth does not

the rough has many folds and convolutions where as the smooth does not

the rough has ribosome embedded and the smooth does not

the rough is closer to the cell membrane whereas the smooth is closer to the nucleus

Question 10

The site where many lipids, including cell membrane is produced.

Question 11

Name the organelle: In muscle cells in particular, I would increase in number and size in response to frequent exercise

Question 12

In animal cells, glucose would be mobilized from its storage molecule (glycogen) in this part of the cell.

Question 13

Which of these is associated with the rough ER

production of carbohydrates

production of steroid hormones

production of ATP

production of proteins that are secreted from the cell

Question 14

Which organelle sorts, modifies and stores substances produced on the rough ER. Write two words as the answer in lower case separated by a space.

Question 15

Which organelle is responsible for ATP production. Write one word in the singular as the answer.

Question 16

You inherit all of your mitochondria from your

father

half from your mother and half from your father

your siblings

mother

Question 17

An organelle that contains chlorophyll

Question 18

Microtubules have a variety of roles, which of the options below is NOT one of them?

separate chromosomes

cilia and flagellum movement

tracks for organelle movement

constrict the cell during cell division

Question 19

Made of tubulin subunits

microfilaments

chromosomes

intermediate filaments

microtubules

Question 20

Name the part of the cytoskeleton that is made of two twisted rods of actin. Write one word as the answer in lower case.

Question 21

Which part of the cytoskeleton is made of the same protein as your hair and nails?

microfilaments

microtubules

Intermediate filaments

Question 22

The extracellular matrix is found outside of, but attached to the cell membrane?

True

False

Question 23

Which of the options below is an important function of the extra cellular matrix?

connecting cells together

regulate the movement of substances into and out of the cell

helping cells divide into two cells

keeping the cell in a fixed and ridged shape

Question 24

Which part of the cell wall has a high pectin content?

Question 25

Plants have mitochondria, chloroplasts, a cell wall, and nuclei.

True

False

Question 27

What accounts for 40% of the protein in our bodies?

Question 28

Animal cells have cell walls

True

false

Exercise Pharmacology

Chapter 1

1. Distinguish between pharmacokinetics, pharmacodynamics, and pharmacology.

2. How would you determine a drugâs doseâresponse curve?

3. What is meant by drug efï¬cacy? Potency?

4. How would you determine equipotent doses for two drugs of the same class?

5. What features of a drugâs action may make its pharmacokinetic properties more sensitive to exercise?

6. How might a drugâs volume of distribution be altered in the case of a person who is obese? A person who is elderly?

7. How might you explain an antagonist with partial agonist activity?

8. What are some of the ways that taking a second drug can affect the activity of the ï¬rst drugâor either drug?

Chapter 2

1. Bill is 60 years old and in reasonable shape. Working out on an elliptical machine, Bill sees that his heart rate is 135 bpm. Can you determine his ap-proximate exercise intensity without hooking him to a metabolic cart? What is he primarily burning for energy?

2. Your mother asks your advice about starting an exercise program. She is in pretty good health, but wants to drop some weight besides improving her cardiovascular health. What kind of exercise plan would you recommend to get her started? How would you explain to her the beneï¬ts of such a plan? After the initial couple of weeks, would you recommend any changes that might help her with her long-term ï¬tness goals?

3. Compare and contrast the three major muscle ï¬ber types in terms of their metabolism and fuel preference.

4. You are a graduate student working in an exercise physiology lab. You see a claim in a bodybuilding magazine about a supplement that rapidly increases power, strength, and muscle mass. How would you set up an experiment to test whether these claims are true?

5. Obesity is now considered by some to be reaching epidemic proportions. What is contributing to this trend, and what can be done?

Chapter 3

1. Compare and contrast the sympathetic and parasympathetic nervous systems.

2. What is meant by allostatic load, and how does it differ from stressing over a single test?

3. Explain three ways drugs can affect the signals transmitted by nerve cells.

4. How might exercise lessen the effects of stress?

5. Describe some of the theories that attempt to explain the bodyâs paradoxical response to exercise.

6. What are the key physiological changes that occur during the ï¬ght or ï¬ight response? How do they help in survival?

Chapter 4

1. What is meant by âbeta-blockers with ISAâ? What advantages might these drugs have? Disadvantages?

2. What property makes some beta-blockers cardio selective?

3. What are the effects of beta-blockers on exercise physiology?

4. A serious walker (5 miles/day) notices that she has stopped losing weight since starting her new prescription of propranolol (non-cardio selective, without ISA). She also fatigues more quickly than she used to. What can you offer her as an explanation?

5. The NCAA and USOC have banned beta-blockers from many types of com-petition. Why?

Chapter 5

1. Bill, a deconditioned, recently divorced 50-something exec driving that new BMW, wants to drop some weight and look good. He has high blood pressure. What kind of exercise regime would you recommend?

2. Why do calcium channel blockers mostly affect smooth muscle, with little effect on skeletal muscle?

3. How do calcium channel blockers reduce blood pressure?

4. Mary enjoys running and likes to compete in 10K races and half marathons. She also is diagnosed with high blood pressure. What are her options for regulating her blood pressure while maintaining a training schedule and remaining competitive?

5. How do ACE inhibitors affect blood pressure?

6. How do ARBs affect blood pressure?