Muscles

Question 1

Types of muscles

Answer 1

Smooth
Cardiac
Skeletal

Question 2

which muscles are striated

Answer 2

cardiac
skeletal

Question 3

how is skeletal muscle attached to bone

Answer 3

via tendons

Question 4

features in skeletal muscle

Answer 4

cell membrane
myofibril
sarcoplasm
myofilaments

Question 5

what is within myofibrils

Answer 5

lots of myofilaments

Question 6

what is within myofilaments

Answer 6

actin and myosin

Question 7

what are the units in myofilaments

Answer 7

sarcomeres

Question 8

is actin thick or thin

Answer 8

thin

Question 9

is myosin thick or thin

Answer 9

thick

Question 10

what is the dark band

Answer 10

A band

Question 11

what the light band

Answer 11

I band

Question 12

what line is myosin attached to

Answer 12

M line

Question 13

what is actin anchored to

Answer 13

Z discs

Question 14

sliding filament theory

Answer 14

1. Ca2+ are released from the SER into the sarcoplasm
2. Ca2+ diffuse and bind to troponin
3. causing a conformational change to the tertiary structure
4. causing tropomyosin to move away exposing the myosin head binding sites on actin
5. myosin heads bind to actin bindings dorming cross bridges
6. myosin heads bend pulling the actin filament (power stroke)
7. ADP + Pi are released from myosin head
8. new ATP binds to myosin heads
   9a. breaks cross bridges and separates it from actin
   9b. ATP hydrolysis to ADP and Pi (recovery stroke)
9. process repeats pulling the actin along

Question 15

what is ATP required for

Answer 15

sliding of filaments during contraction

the active transport of calcium to the SER

Question 16

role of Ca2+ ion

Answer 16

Ca2+ ions are actively transported back into Sarcoplasmic ER

Ca2+ ions also activate ATP Hydrolase

Question 17

describe the role of phosphocreatine

Answer 17

provide phosphate
to synthesis ATP

Question 18

how do slow twitch fibres work

Answer 18

produce slow sustained contractions over long time periods but have a slower rate of contractions

eg. calves

Question 19

how do fast twitch fibres work

Answer 19

produce rapid strong contractions as have a faster speed of contractions but only sustained over a short period of time

muscles which contain this fibre are fast to fatigue due to a buildup of lactate

Question 20

properties of slow twitch fibres

Answer 20

darker in colour
more mitochondria
more capillaries
less glycogen
less phosphocreatine
less sarcoplasmic ER
less calcium ions
slow sustained contractions
less force
slow fatigue
aerobic respiration

Question 21

properties of fast twitch fibres

Answer 21

more pale
more glycogen
more phosphocreatine
more sarcoplasmic ER
more calcium ions
rapid strong contractions
more force
fast fatigue
anaerobic respiration

Question 22

People who have McArdle’s disease produce less ATP than healthy people. As a result, they are not able to maintain strong muscle contraction during exercise. Use your knowledge of the sliding filament theory to explain why

Answer 22

(Idea ATP is needed for:) 1. Attachment/cross bridges between actin and myosin; 2. ‘Power stroke’ / movement of myosin heads / pulling of actin; 3. Detachment of myosin heads; 4. Myosin heads move back/to original position / ‘recovery stroke’;