Muscle fibres

Question 1

Skeletal muscles

Answer 1

Are attached to your skeleton (bones)

Question 2

What are muscle made of

Answer 2

Muscle fibres

Question 3

What are muscle fibres made up of

Answer 3

Myofribils (actin and myosin)

Question 4

What are the adaptions of a muscle fibre

Answer 4

Multinucleate
It has lots of mitochondria for respiration for energy
The cell membrane (sarcolemma)
Made up of myofribils (actin and myosin)

Question 5

What does muscle fibres have in its diagram

Answer 5

• striated (actin and myosin make them appear more stripy
• Multinucleat
• cell membrane ( sarcolemma)

Question 6

What are myofribils composed of
What are sarcomeres composed of

Answer 6

numerous sarcomeres
myofilaments

Question 7

What are the myofilaments made of

Answer 7

Actin- think proteins
Mysosin- thick protein

Question 8

What happens when your muscle contracts

Answer 8

The calcium ions bind to the troponin which pulls the tropomyosin along, revealing the myosing binding sites

Question 9

Describe and contrast fast twitch muscles

Answer 9

Fast twitch muscles happen when the muscles contracts faster and releases energy more quickly
-uses anerobic respiration (no oxygen)
- fewer blood vessels because of less blood supply because of anerobic respiration
- less myoblin : myoblin is an oxygen store and oxygen is not needed

Question 10

Describe and contrast slow twitch muscles

Answer 10

Slow twitch muscles contracts slower and releases energy more slowly
- uses aerobic respiration (use oxygen)
- more mitochondria
- produces more ATP and releases more energy from glucose

Question 11

What are the 8 steps of muscle contraction

Answer 11

1. action potential is sent to a muscle down a neurone
2. The action p reaches the neuromuscular junction and passes into the sarcolemma
3. Action potential travels from the sarcolemma - fibre cell - t tuble
4. The action potential causes the sarcoplasmic reticulum to release calcium ions which bind to troponin pillung tropomyosin along, revealing myosin binding sites
5. ADP binds. myosin head binds to actin
6. ATP binds to the myosin head: causes myosin to detach from actin
7. ATP is broken down into ADP + Pi: causes myosin head to change angle
8. ADP + Pi released: causes myosin head to change angle and pull actin along

Question 12

What are the stages for the sliding filament theory

Answer 12

5. ADP binds. myosin head binds to actin
6. ATP binds to the myosin head: causes myosin to detach from actin
7. ATP is broken down into ADP + Pi: which causes myosin head to change angle
8. ADP + Pi released: which causes myosin head to change angle and pull actin along