Module 3

Question 1

What two molecular motors are found on microtubules?

Answer 1

Kinesin and Dynein

Question 2

What are three ways to enable movement by the cytoskeleton

Answer 2

1. Cytoskeleton “roadway” and motor protein carriers
2. Reorganization of cytoskeletal network
3. Motor proteins pull on the cytoskeletal “rope”

Question 3

What structure organizes microtubules?

Answer 3

Microtubule organization center (-)

Question 4

In which direction does dyenine walk? Kinesin?

Answer 4

Negative, positive

Question 5

At which end does the microtubule grow faster?

Answer 5

The + end

Question 6

Define dynamic instability

Answer 6

Balance between growth and shrinkage

Question 7

Define Microtubule Associated Proteins

Answer 7

Proteins that contribute to the dynamic instability and organization of microtubules

Question 8

Which microtubule associated motor protein is faster at walking?

Answer 8

Dyenin is 5x faster than kinesin

Question 9

What are microfilaments composed of?

Answer 9

Actin

Question 10

What are the two sources of movement for microfilaments?

Answer 10

1. Actin polymerization

2. Sliding filament model

Question 11

Actin comes in two different forms. What form is associated with a polymer, and what form is associated with filaments?

Answer 11

G-actin, F-actin

Question 12

What end of a microfilament grows faster?

Answer 12

The + end (6-10x faster)

Question 13

Define capping proteins in the context of microfilaments

Answer 13

Capping proteins

Question 14

What is the motor protein used for microfilaments?

Answer 14

Actin

Question 15

What are the three parts of myosin

Answer 15

Head, neck, tail

Question 16

In the sliding filament model, the analogy of a rope and arm is used. For actin and myosin, which is each?

Answer 16

Actin -> the rope

Myosin -> your arm

Question 17

Define the cross-bridge cycle

Answer 17

formation of attachment, power stroke, and release

Question 18

Define unitary displacement

Answer 18

Distance myosin steps during each cross-bridge cycle

Question 19

What two factors impact unitary displacement?

Answer 19

1. Myosin neck length

2. Myosin placement

Question 20

Define duty cycle

Answer 20

cross bridge cycle time