contraction of skeletal muscle

Question 1

what does the sarcoplasm have a lot of

Answer 1

mitochondria

Question 2

where are the myofibrils found

Answer 2

sarcomere

Question 3

what are the two components of myosin

Answer 3

fibrous filament
globular

Question 4

what is actin made of

Answer 4

globular proteins
tropomyosin

Question 5

what is tropomyosin

Answer 5

long chains around actin

Question 6

what is the first step of muscle contraction

Answer 6

calcium ions enter the sarcoplasmic reticulum

Question 7

how do calcium ions enter

Answer 7

through active transport

Question 8

how does calcium ions enter and where does it go from

Answer 8

active transport from the sarcoplasm to the sarcoplamic reticulum

Question 9

what does the presence of calcium ions cause

Answer 9

tropomyosin to move off the actin exposing actin binding sites

Question 10

what does the exposing of actin binding sites mean

Answer 10

myosin head binds to actin binding site

Question 11

what also binds to the actin-binding site

Answer 11

adp

Question 12

what is created when the myosin head binds to actin binding site

Answer 12

crossbridge

Question 13

how does this then cuase muscle contraction

Answer 13

myosin head then becomes cocked and pulls the actin over the myosin

Question 14

what does the pulling of the actin over the myosin cause

Answer 14

causes ADP to be released

Question 15

after ADP is released what happens to the myosin head

Answer 15

an ATP molecule binds to myosin head

Question 16

what does the binding of ATP onto myosin cuase

Answer 16

causes the myosin head to dettach from the actin

Question 17

once dettached then what happens

Answer 17

ATP is hydrolised

Question 18

what is Atp hydrolised by

Answer 18

ATPase

Question 19

what does the hydrolisis of atp cause

Answer 19

causes the ADP to dettach from myosin head

Question 20

what does dettachment of ATP mean for myosin

Answer 20

myosisn head returns to normal

Question 21

now the myosin head has returned to normal what can happen

Answer 21

ADP and Pi can attach to myosin head

Question 22

what does this mean this process is

Answer 22

cyclical

Question 23

what can help increase speed of muscle contraction

Answer 23

phosphocreatine

Question 24

what does phosphocreatine do

Answer 24

readily supplies phosphate meaning that the conversion / phosphorylation of ADP to ATP can happen more readily