L18: cellular movement

Question 1

vesicle trafficking: from cell body to axon

Answer 1

moving from the - side to the + side
kinesin
-movement: back foot will move to the front/ front foot bind to b-
tubulin
hydrolysis of atp

Question 2

vesicle trafficking: from axon to cell body

Answer 2

moving from the + side to the - side
dynein
hydrolysis of atp

Question 3

organization of muscles: largest to smallest

Answer 3

muscles–> bundle of muscle fibers (muscle cells)–> individual muscle fiber (cell)–> myofibrils–> single microfibrils–> portion of microfibrils

Question 4

thick filament

Answer 4

myosin
myosin head

Question 5

thin filament

Answer 5

actin
troponin
troponin complex

Question 6

sarcomere

Answer 6

the contraction unit of the muscle cell

Question 7

what do I band consist of?

Answer 7

only thin filament (actin)

Question 8

what does A band consist of?

Answer 8

only thick filament (myosin)

Question 9

what is the M line?

Answer 9

the center of the sarcomere
the middle of the thick filaments of a band

Question 10

what does the H zone consist of?

Answer 10

center of a band
no overlap between thin and thick filament
only thick filament

Question 11

what is z line?

Answer 11

the middle of I band( thin filament)
z-z= sacromere

Question 12

what happens to the sarcomere when it is contracted?

Answer 12

thin and thick filament slide across each other (do not shorten)

with of
a band: constant
H zone: smaller
I band: smaller

Question 13

how does contraction occur?

Answer 13

1. cross-bridge form with myosin head
2. release Pi–> myosin head binding to troponin complex (with adp)
3. adp disassociate/ released–> myosin bind to actin–> move towards the sarcomere(right to left)
   —-now myosin head is low in energy
4. atp bind to myosin–> myosin head detach from actin (no head-still l
   low in energy)
   5.atp breakdown(hydrolysis)–> making a myosin head with adp+pi =high energy

Question 14

how does a neuromuscular get depolarized?

Answer 14

1. action potential move down the axon of the neuron to the neuromuscular junction (synapse of neuron and muscle cell)===> membrane gets depolarized
2. neurotransmitters is released—> bind to acetylcholine of muscle cell===> depolarization of the muscle cell
3. depolarization spread thru t tubules==> stimulating ca+ release from the cisternae of the SR

Question 15

how do actin filaments attach

Answer 15

through focal adhesion

Question 16

vesicle trafficking: from cell body to axon

Answer 16

moving from the - side to the + side
kinesin
-movement: back foot will move to the front/ front foot bind to b-
tubulin
hydrolysis of ATP