Question 1

You identify a protein that may play a role in microtubule-based transport.Propose a series of experiments that would aid you in confirming your assessment that this protein has a role in microtubule-based transport.

Accepted Answer

The answer of You identify a protein that may play...

Question 2

The "9 + 0" pattern of microtubules is associated with

Accepted Answer

A) bacterial locomotion. 
B) cyanobacterial locomotion. 
C) respiratory tract cilia. 
D) sperm tail flagella. 
E) primary (sensory)cilia.

Question 3

Kinesin 1 is highly processive motor,taking more than 100 steps (covering 1 μm along a microtubule)before dissociating,primarily because

Accepted Answer

A) it hydrolyzes ATP more rapidly than other motors. 
B) one of its two heads is always attached in it hand-over-hand mechanism. 
C) light chains at its nonmotor end attach to cargo vesicles. 
D) its efficiency of converting ATP hydrolysis energy to useful work is 60-70%. 
E) All are required for processivity.

Question 4

Crawling cells produce broad,thin protrusions known as ________ and pointed structures called ________ at the leading edge of the cell.

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The answer of Crawling cells produce broad,thin protrusions known as...

Question 5

Eukaryotic motile cilia and flagella have similar structures but vary in number,length,and function.For each of the following,compare/contrast cilia and flagella.
a.number present per cell
b.length of appendage
c.direction of force generated relative to the direction of the appendage
d.function in unicellular and multicellular eukaryotes
e.motion analogy

Accepted Answer

The answer of Eukaryotic motile cilia and flagella have similar...

Question 6

________ links the thick filaments to the Z line.

Accepted Answer

A) Troponin 
B) Tropomyosin 
C) Titin 
D) Nebulin 
E) Myomesin

Question 7

Arp2/3-dependent actin polymerization directly drives which of the following activities at the leading edge of crawling cells?

Accepted Answer

A) filament rearward translocation 
B) lamellipodia protrusion 
C) new adhesion formation 
D) generation of tension 
E) focal adhesion detachment

Question 8

Which of the following would you use to inhibit the contraction of muscle in vitro as a control for an experiment you are conducting?

Accepted Answer

A) a drug that increases sarcoplasm Ca2+ concentration 
B) a motor protein ATPase inhibitor 
C) a Ca2+-ATPase inhibitor 
D) a drug that increases T-tubule depolarization 
E) All would inhibit muscle contraction.

Question 9

Which of the following lists of structures is in the correct order from inside to outside of the cell?

Accepted Answer

A) axoneme,transition zone,basal body 
B) transition zone,basal body,axoneme 
C) axoneme,basal body,transition zone 
D) basal body,transition zone,axoneme 
E) basal body,axoneme,transition zone

Question 10

Axonemal dyneins are

Accepted Answer

A) associated with organelle movement. 
B) associated with cilia and flagella. 
C) monomeric myosin-like proteins. 
D) responsible for axonal anterograde transport. 
E) All of the above are correct.

Question 11

Rigor mortis after death is caused by myosin crossbridges that fail to dissociate from the actin thin filaments because of lack of ________.

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The answer of Rigor mortis after death is caused by...

Question 12

________ is the process that moves tubulin subunits to the flagellar tip where they assemble onto axonemal microtubules.

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The answer of ________ is the process that moves tubulin...

Question 13

Explain why myosin II in a sarcomere can produced force only for that sarcomere contraction and not for that sarcomere extension.

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The answer of Explain why myosin II in a sarcomere...

Question 14

In relaxed muscle,Ca2+ is found in highest concentration in the

Accepted Answer

A) sarcoplasm. 
B) T tubules. 
C) sarcoplasmic reticulum. 
D) sarcolemma. 
E) neuromuscular junction.

Question 15

In the T-tubule triad structure seen in electron micrographs of striated muscle,the T tubule is flanked by two terminal cisternae of the ________.This association facilitates opening terminal cisternae ryanodine receptors,which ________ to initiate sarcomere contraction.

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The answer of In the T-tubule triad structure seen in...

Question 16

Cyclosis (cytoplasmic streaming)is driven by ________ that interact with ________ that are anchored to chloroplasts near an algal cell wall.

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Question 17

The tetanus toxin tetanospasmin blocks release of the neurotransmitter (GABA)that inhibits motor neurons and decreases muscle contraction.This causes persistence of the signal to contract and the resulting violent muscle contraction known as tetanic spasm.Compare the sustained contraction of muscle cells in rigor mortis with muscle contraction caused by the action of tetanospasmin on motor neurons.

Accepted Answer

The answer of The tetanus toxin tetanospasmin blocks release of...

Question 18

Which of the following major protein components of skeletal muscle is incorrectly matched with its function?

Accepted Answer

A) titin-links thick filaments to Z line 
B) nebulin-links thin filaments to Z line 
C) myomesin-links myosin bipolar filaments at M line 
D) troponin-binds along the length of the thin filaments and blocks myosin binding sites 
E) actin-major component of thin filaments

Question 19

Addition of ATP to isolated axonemes causes localized bending.What can be done to the isolated axonemes to cause the outer doublets to slide past each other unrestrained,lengthening the overall structure instead of causing bending?

Accepted Answer

A) add gelsolin 
B) remove the interdoublet nexin links 
C) add nocodazole 
D) remove the ATP 
E) inhibit tektin activity with a drug

Question 20

Myosin II is ideally suited for muscle contraction because it forms ________ filaments.

Accepted Answer

The answer of Myosin II is ideally suited for muscle...

Exam 14: Cellular Movement: Motility and Contractility