Topic 7

Question 1

Give a difference between flexor muscles and extensor muscles

Answer 1

Flexors are muscles that bend joints when they contract. Extensors straighten joints when they contract.

Question 2

Give a similarity between flexor muscles and extensor muscles

Answer 2

They are both examples of skeletal muscles, which are muscles that move the limbs and other parts of the body.

Question 3

Define antagonistic pairs of muscles

Answer 3

Muscles that work together to move a bone

Question 4

Why do muscles have to work together in antagonistic pairs?

Answer 4

Muscles can only pull. This would be a problem if a joint was controlled by just one muscle because there no way to move the bone back again.

Question 5

Explain the differences in the structures of fast twitch and slow twitch muscle fibres.

Answer 5

• Slow twitch fibres have more mitochondria
• Slow twitch fibres have more capillaries
• Slow twitch fibres have more myoglobin
• Slow twitch fibres respire aerobically and fast twitch respire anaerobically

Question 6

Explain what is meant by the term ‘oxidative phosphorylation’

Answer 6

electrons being passed along an electron transport chain
losing energy at each step
the energy is used to phosphorylate ADP
oxygen is the final electron acceptor