2 cellular Cytoskeletal elements Immunohistochemical stains for intermediate filaments Microtubule Cilia structure Plasma membrane composition Na/K pump

Question 1

What purposes do cilia, flagella, mitotic spindles, centrioles, and axonal trafficking serve? What cytoskeletal element do they all require?

Answer 1

Movement and cell division; microtubules

Question 2

Name six compounds that are composed of intermediate filaments.

Answer 2

Vimentin, desmin, cytokeratin, lamins, glial fibrillary acid proteins (GFAP), neurofilaments

Question 3

What is the prototypical microfilament that contributes to muscle contraction and cytokinesis?

Answer 3

Actin

Question 4

Vimentin stains identify which type of cells?

Answer 4

Connective tissue

Question 5

Which type of cell do desmin stains identify?

Answer 5

Muscle (desMin = Muscle)

Question 6

Cytokeratin stains identify which type of cells?

Answer 6

Epithelial cells

Question 7

Neurofilament stains identify which type of cells?

Answer 7

Neurons

Question 8

What type of cell do glial fibrillary acid protein (GFAP) stains identify?

Answer 8

Neuroglia (GFAP = neuroGlia)

Question 9

Name three cellular structures in which microtubules are found.

Answer 9

Cilia, flagella, and mitotic spindle

Question 10

Microtubule filaments grow ____ (quickly/slowly) and collapse ____ (quickly/slowly).

Answer 10

Slowly; quickly

Question 11

Are microtubules involved in fast or slow transport along the neuronal axons?

Answer 11

Slow axoplasmic transport

Question 12

A man has recurrent attacks of acute inflammatory arthritis with a swollen big toe. What microtubule medication can abort an acute attack?

Answer 12

This is gout, treated with colchicine (inhibits microtubule polymerization by binding to tubulin)

Question 13

Name three anticancer drugs that function by altering the polymerization of microtubules.

Answer 13

Vincristine, vinblastine, and paclitaxel

Question 14

A patient has a fungal infection. You are asked to prescribe an antifungal agent that targets microtubules. What could you prescribe?

Answer 14

• Griseofulvin

Question 15

Which antihelminthic drug targets the microtubules?

Answer 15

Mebendazole

Question 16

• In a microtubule, ____ protein is for anterograde transport; ____ protein is for retrograde transport.

Answer 16

Kinesin (negative–to–positive end); dynein (positive–to–negative end)

Question 17

Name two molecular motor proteins that transport cellular cargo to opposite ends of microtubule tracks.

Answer 17

Kinesin (anterograde transport) and dynein (retrograde transport)

Question 18

Name the two protein constituents of the heterodimer building block for microtubules. How many GTPs are bound to each dimer?

Answer 18

α- and β-tubulin; each dimer is 2 GTP bound

Question 19

How are cilia structurally composed?

Answer 19

Nine microtubule doublets around two central microtubules

Question 20

What protein causes the movement of the cilia?

Answer 20

Axonemal dynein is an ATPase that links the nine peripheral doublets and causes cilia bending by differential sliding of doublets

Question 21

Which diagnosis should you consider in a male patient with infertility, bronchiectasis, and recurrent sinusitis?

Answer 21

Kartagener syndrome (primary ciliary dyskinesia)

Question 22

Can male or female patients, or both, have reduced fertility in Kartagener syndrome?

Answer 22

Both—immotile sperm in male patients; dysfunctional fallopian tube cilia and increased risk of ectopic pregnancy in females

Question 23

A woman has a history of recurrent pneumonia; chest x-ray reveals dextrocardia. If she gets pregnant, what is she at risk for?

Answer 23

Kartagener syndrome (primary ciliary dyskinesia) in which dysfunctional fallopian tube cilia increase the risk for ectopic pregnancy

Question 24

The plasma membrane is a(n) ____ (symmetric/asymmetric) lipid bilayer.

Answer 24

Asymmetric

Question 25

Name five components of plasma membranes.

Answer 25

Phospholipids, cholesterol, sphingolipids, glycolipids, and proteins

Question 26

How many ATPs are consumed in one cycle of the Na-K pump?

Answer 26

One

Question 27

A man takes a drug that boosts cardiac contractility by indirectly raising intracellular Ca2+ levels. Blockade of which pump is responsible?

Answer 27

Cardiac glycosides inhibit Na+/K+ ATPase, causing decreased Na+/Ca2+ exchange and thus more intracellular Ca2+ (increased contractility)

Question 28

Where does ouabain bind to the Na+-K+ ATPase? What does it do to the pump?

Answer 28

At the K+ binding site; it inhibits the pump

Question 29

The ATP binding site of the Na+-K+ ATPase is located on the ____ side of the plasma membrane.

Answer 29

Cytosolic

Question 30

For each ATP consumed by the Na+/K+ pump, three ____ (Na+/K+) ions go ____ (in/out) and two ____ (Na+/K+) ions go ____ (in/out).

Answer 30

Na+; out; K+; in