Quiz 2

Question 1

What would INCREASE the phase transition temperature of a synthetic bilayer composed of phosphatidylserine?

Answer 1

Incorporation of phospholipids with longer fatty acid chains

Question 2

A potassium channel conducts K+ ions several orders of magnitude better than Na+ ions because?

Answer 2

the Na+ ion is too small to interact with the channel that facilitates the loss of water from the ion

Question 3

kinesin-13 motor domain is inserted where?

Answer 3

middle of the heavy chain

Question 4

What is unique about kinesin-13?

Answer 4

M-type kinesin that do not display microtubule-based motility (hand-over-hand) and depolymerizes microtubules

Question 5

Where does kinesin-13 bind on the microtubule?

Answer 5

kinesin-13 binds to microtubule ends

Question 6

For kinesin-13: how does ATP hydrolysis at kinesin-13 motor domain affect the microtubule?

Answer 6

Kinesin-13 does not display microtubule-based motility (hand over hand). Instead it uses ATP hydrolysis to destabilize MT plus-ends to pry protofilaments apart

Question 7

What is FRAP?

What does the diffusion coeffcient of FRAP tell you?

**question 5 multiple choice

Answer 7

Fluorescence recovery after photobleaching measures the rate of lateral diffusion of a membrane protein by fluorescence recovery after photobleaching

the greater the diffusion coefficient of a protein, the faster the recovery

Question 8

What is FRAP?

What does the diffusion coeffcient of FRAP tell you?

**question 5 multiple choice

Answer 8

Fluorescence recovery after photobleaching measures the rate of lateral diffusion of a membrane protein by fluorescence recovery after photobleaching

the greater the diffusion coefficient of a protein, the faster the recovery

Question 9

Sanshool is a natural compond found in Sichuan pepper.

It is known to inhibit a subset of K+ leak channels involved in maintaining the resting membrane potential in sensory neurons. How do you think sanshool affects these sensory neurons?

Answer 9

Sanshool inhibits subset of K+ leak channels involved in maintaining resting membrane potential.

It elevates the resting potential making it easier to excite the neuron

Question 10

Unlike a myosin head, a kinesin head is tightly bound to its cytoskeletal track when bound to?

Answer 10

ATP

Question 11

Which of the following is a pump that hydrolyzes two ATP molecules per transport cycle?

Answer 11

The multidrug resistance protein (ABC transport)

Question 12

Cholesterol

Answer 12

flip-flops relatively often

Question 13

Phosphatidylserine

Answer 13

has negatively charged headgroup

Question 14

V-type ATPase

Answer 14

pumps H+ across membrane

Question 15

Gm1 ganglioside

Answer 15

has branched sugar instead of headgroup

Question 16

Integrin

Answer 16

spans membrane with single a-helix

Question 17

What are the four actin-binding proteins?

Answer 17

1. myosin
2. a-actinin
3. CapZ
4. Arp2/3

Question 18

Arp2/3

Answer 18

stabilizes minus end and nucleates assembly to form a web

Question 19

capZ

Answer 19

binds and stabilizes actin-plus end (localized to Z-band in muscles)

Question 20

a-actinin

Answer 20

organizes plus end

Question 21

myosin

Answer 21

myosin protein associates with actin to form the contractile filaments of muscle cells

Question 22

Phosphorylation of V-type proton pump and F-type ATP synthase

Answer 22

proton transport functions like a turbine (multiple subunits)

Question 23

Phosphorylation of P-type pump

Answer 23

ion transport

Question 24

Phosphorylation of ABC transporter

Answer 24

2 ATP molecules, small molecule transport