Muslces

Question 1

What happens at contraction

Answer 1

-A band remains constant
-H zone , myosin ,shortens
-I band , actin , shortens

Question 2

Sliding filament theory

Answer 2

-Action potential stimulates muscle
-Calcium ions enter and cause tropomyosin to move to expose binding sites
-ADP which is attached to myosin head as it binds to actin forming cross bridge
-Cross bridge creates tension and pulls myosin to release ADP and pi
-ATP hydrolase is then activated by calcium ions which hydrolyses ATP into ADP releasing energy for contraction

Question 3

Phosphocreatine

Answer 3

Provides phosphate to regenerate ATP from ADP

Question 4

Difference between slow twitch and fast twitch muscle fibres

Answer 4

-Slow have large store of myoglobin , lots of mitochondria , fast have thicker myosin filaments a large glycogen store along with anaerobic respiration enzymes
-Slow = calves , fast = biceps
-Slow contract slower for longer periods , aerobically whereas fast contract quicker and more intense anaerobic