Unit 2: Cytoskeleton

Question 1

Motor proteins provide for molecular motion in cells by interacting with ____

Answer 1

components of the cytoskeleton

Question 2

A characteristic 9 + 2 arrangement of microtubules, consisting of nine doublet microtubules surrounding a pair of single microtubules describes the ultrastructure of

Answer 2

eukaryotic flagella and motile cilia

Question 3

Movement of amoebae across a surface requires

Answer 3

assembly of actin filaments to form bulges in the plasma membrane

Question 4

______ is required by cells to assemble cilia or flagella

Answer 4

tubulin

Question 5

Bending of cilia and flagella results from

Answer 5

conformational changes in a motor protein called dynein

Question 6

Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer.

Cancer cells treated with vinblastine would most likely be unable to perform this celular function:

Answer 6

separate chromosomes during cell division

Question 7

Researchers investigating the mechanism of vesicle transport assembled a cell-free system that included microtubules, vesicles, and ATP.

However, they observed no movement of transport of vesicles because the mixture was missing this protein __________

Answer 7

motor proteins

Question 8

Certain animal cells normally have well-defined spherical nuclei when observed by light microscopy.

Cells with a genetic defect have irregularly-shaped nuclei. Which cytoskeletal element is most likely affected by this genetic defect?

Answer 8

intermediate filaments

Question 9

Cytochalasin D is a drug that prevents actin polymerization. Which of the following processes will be unaffected in cells treated with cytochalasin D?

A) cytoplasmic streaming
B) contraction of muscle fibers
C) extension of pseudopodia
D) movement of transport vesicles in the cytosol

Answer 9

D) movement of transport vesicles in the cytosol

Question 10

Which of the following statements best describes some aspect of cytoskeleton structure or function in eukaryotic cells?

A) The cytoskeleton is a static structure most resembling scaffolding used at construction sites.
B) Although microtubules are common within a cell, actin filaments are rarely found outside of the nucleus.
C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
D) Chemicals that block the assembly of the cytoskeleton would have little effect on a cell’s response to external stimuli.

Answer 10

C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.