musthle

Question 1

what are the three main types of muscle

Answer 1

skeletal, cardiac and smooth

Question 2

what does skeletal muscle do

Answer 2

used to move limbs

Question 3

what does smooth muscle do

Answer 3

used to move substances through organs

Question 4

what does cardiac muscle do

Answer 4

used to pump blood

Question 5

what is the name for the type of pairs that skeletal muscle comes in and what does it mean

Answer 5

antagonistic pairs, as one contracts the other relaxes

Question 6

which types of muscles are striated

Answer 6

cardiac and skeletal

Question 7

which type of muscle is branched

Answer 7

cardiac

Question 8

which type of muscle is multinucleated

Answer 8

skeletal

Question 9

what is a muscle fibre

Answer 9

a muscle cell

Question 10

what are myofibrils

Answer 10

the tube like structures that are inside the muscle fibres

Question 11

what are the two types of protein filaments within the myofibrils

Answer 11

actin and myosin

Question 12

what are actin filaments made of

Answer 12

two actin filaments wrapped around each other and tropomyosin

Question 13

what are myosin filaments made up of

Answer 13

two myosin filaments wrapped around each other with a head and a tail

Question 14

what is a sarcomere

Answer 14

a section inside a myofibril that is made up of a vertical stack of at least 4 thin filaments and one thick filament, repeats

Question 15

what is the middle of a sarcomere in the thick filaments called

Answer 15

the M line

Question 16

what is the line at the midpoint of two M lines called

Answer 16

the Z line

Question 17

how many Z lines and M lines are there in one sarcomere

Answer 17

1 M line and 2 Z lines

Question 18

which areas of a sarcomere are light and dark

Answer 18

the thin filaments appear as light and the thick filaments appear as dark

Question 19

what are I bands

Answer 19

the areas of a sarcomere that appear lighter

Question 20

what are the A bands

Answer 20

the areas of a sarcomere that appear darker

Question 21

what is the H zone in a sarcomere

Answer 21

the lighter bit in the dark bit (a band ), appears lighter because its made of only thick filaments

Question 22

what triggers the actin and myosin to move

Answer 22

an action potential in the muscle fibre, calcium ions

Question 23

what does calcium trigger within a myofibril

Answer 23

triggers tropomyosin to change shape and move away from the binding sites

Question 24

within the muscle fibre where are calcium ions released from

Answer 24

the sarcoplasmic reticulum

Question 25

when the myosin head attaches to the binding site on the actin what does it form

Answer 25

actinomyosin bridge

Question 26

what reaction myosin heads catalyse

Answer 26

the conversion of ATP into ADP and a phosphate ion

Question 27

what does the energy from the hydrolysis of ATP allow the myosin head to do

Answer 27

take its starting position

Question 28

what happens when the myosin attaches to the actin binding site

Answer 28

ADP and the phosphate ion are released from the myosin head active site which allows the myosin head to change its angle and move the actin (the power stroke)

Question 29

what happens after the myosin head has completed the power stroke

Answer 29

another molecule of ATP comes along and binds to the myosin head causing it to detach from the actin, myosin head hydrolyses ATP which releases energy and allows it to go back to its starting position

Question 30

what is the name of the mechanism for which muscles contract

Answer 30

the sliding filament mechanism

Question 31

on a microscopic image how does a contracted sarcomere look different to a relaxed one

Answer 31

a contracted sarcomere has a smaller H zone, the whole sarcomere is shorter, z lines move closer together

Question 32

how does muscle relaxation come about

Answer 32

the calcium ions are actively transported back into the sarcoplasmic reticulum so the tropomyosin moves back to cover the actin binding sites and the myosin heads move back down