1.8. Energy Systems in Muscle Cells

Question 1

What is creatine phosphate?

Answer 1

A substance that acts as a reserve of phosphates and energy in muscle and brain cells. It can be quickly broken down to release phosphates and energy during intense muscle effort. Excess ATP can be used to regenerate creatine phosphates during rest periods.

Question 2

How is lactic acid created during exercise and what does too much of it cause?

Answer 2

During exercise, the oxygen demand is too much to be satisfied just by breathing and through blood so muscle cells convert pyruvate to lactic acid (fermentation). This process also produces NAD allowing exercise to continue.
Too much lactic acid causes acidosis (painful muscles).

Question 3

Where is skeletal muscle found?

Answer 3

Connected to the skeleton by tendons.

Question 4

What are the two types of skeletal muscle?

Answer 4

Slow twitch (type 1) and fast twitch (type 2).

Question 5

What are slow muscle fibres good for?

Answer 5

Endurance activities like marathon running. They sustain contractions for long periods of time. They are dense and rich in mitochondria and myoglobin. They use stored fats as their energy source.

Question 6

What are fast muscle fibres good for?

Answer 6

Rapid movements. They have less capillaries and mitochondria and less myoglobin. They contract quicker but get tired quicker too.