32. Biological Motion

Question 1

What is duty ratio?

Answer 1

Ratio of time spent in the attached state over the whole cycle time

Question 2

What is the range of forces generated by one single motor protein?

Answer 2

1-10pN

Question 3

How do you calculate stroke velocity?

Answer 3

Working distance of protein / time spent in attached state

Question 4

Work formula

Answer 4

W = F*s

S : displacement

Question 5

How do you calculate power?

Answer 5

P = W / t or F*v

Question 6

What is this equation?

(F+a)(v+b)=(F0+a)b

Answer 6

Hill equation : shows relationship between force and velocity is hyperbolic
F : force
V : shortening velocity
A and b : constants 
F0 : maximal isometric force

Question 7

What is a cross bridge?

Answer 7

Myosin heads attached to active sites on actin filament

Question 8

What are motor proteins?

Answer 8

mechanoenzymes capable of converting chemical energy into mechanical work

Question 9

What is the role of the globular head of the motor protein

Answer 9

motor domain, binds and hydrolyzes nucleotides

Question 10

4 steps of cylic operation of motor proteins

Answer 10

1. Attachment
2. Power stroke
3. Detachment
4. Back stroke

Question 11

5 types of motor proteins

Answer 11

1. Actin-based
2. Microtubule based
3. DNA-based
4. Rotary motors
5. Mechanoenzymes

Question 12

What is the tail of myosins like?

Answer 12

alpha helix coil

Question 13

2 types of dynein

Answer 13

axonemal or cytoplasmic

Question 14

What is the enzymatic function of dynein?

Answer 14

GTP-ase enzyme (for protein sorting)

Question 15

What do rotary motors do?

Answer 15

generate rotational motion using the H+ gradient

Question 16

Which rotary motor protein is responsible for ATP synthesis in the inner mitochondrial mb?

Answer 16

F1F0 ATP synthase

Question 17

What is the range of working distance?

Answer 17

nm range

Question 18

What are the 3 types of responses to stimulus/stimuli?

Answer 18

Twitch, wave summation, tetanus

Question 19

What is the unit of power?

Answer 19

Watt aka kg * m² * s-3

Question 20

At approximately which % of velocity is Pmax?

Answer 20

at 30%

Question 21

Which molecule does Ca2+ bind to?

Answer 21

troponin