Fast And Slow Twitch Muscles

Question 1

Compare contraction of slow and fast twitch muscles.

Answer 1

Slow: contract slowly for longer periods of time
Fast: contract quickly for shorter periods of time

Question 2

What types of activity are fast and slow twitch muscles used for?

Answer 2

Slow: good for endurance
Fast: good for short, speedy and powerful activity

Question 3

What type of respiration do slow and fast twitch muscles use?

Answer 3

Slow: adapted for aerobic respiration
Fast: adapted for anaerobic respiration

Question 4

Compare the number of mitochondria in fast and slow twitch muscles.

Answer 4

Slow: many mitochondria found at the edge of the muscle fibres
Fast: fewer mitochondria

Question 5

Compare the blood supply to slow and fast twitch muscles.

Answer 5

Slow: many capillaries so lots of oxygen supplied for aerobic respiration
Fast: fewer capillaries as less oxygen needed due to anaerobic respiration

Question 6

Why do fast twitch muscle result in fatigue?

Answer 6

Produce lactic acid due to anaerobic respiration which leads to low pH and muscle fatigue

Question 7

Why do slow twitch muscles contain lots of myoglobin?

Answer 7

• provides the muscles with a red colour
• acts similarly to haemoglobin which is an oxygen store

Question 8

Why do fast twitch muscles contain lots of glycogen?

Answer 8

Hydrolyses quickly to release lots of glucose for glycolysis

Question 9

Compare the colour of slow and fast twitch muscles.

Answer 9

Slow: red due to having lots of myoglobin
White: due to containing no myoglobin