1.8 energy systems in muscle cells Flashcards
State the conditions during which lactate metabolism in muscle cells will occur.
If muscle cells do not get sufficient oxygen to support the electron transport chain then the pyruvate will be converted to lactate. This can happen during vigorous exercise when conditions in the muscle cells become anaerobic.
Describe the process of lactate metabolism in muscle cells and state the key role of NAD / NADH in this process.
During lactate metabolism, pyruvate (3-carbon compound) is converted to lactate (another 3-carbon compound). This conversion involves the transfer of hydrogen from the NADH produced during glycolysis to the pyruvate in order to produce lactate. This transfer of hydrogen regenerates the NAD needed to allow glycolysis to continue to maintain ATP production.
State the term used to describe muscles as lactate accumulates within them.
When lactate accumulates within muscles they are said to be fatigued.
Identify the organ where lactate is converted back to pyruvate and glucose.
Lactate is converted back to pyruvate and glucose in the liver.
Describe what happens in the body during ‘oxygen debt’ following a period of vigorous exercise.
At the end of period of vigorous exercise, the body is said to be in oxygen debt due to the build-up of lactate within the bloodstream
What happened in the body during the recovery of vigorous exercise
During the recovery period, the oxygen debt is repaid. During this recovery period, oxygen is used to allow respiration to provide the energy to convert lactate back to pyruvate and glucose in the live
What happens when all the lactate is removed in terms of oxygen debt
When all the lactate has been removed, the oxygen debt will have been paid and the body cells will return to normal aerobic respiration.
Identify the two types of muscle fibre found in skeletal muscle.
The two types of muscle fibres found in skeletal muscle are :
· Fast-twitch fibres
· Slow-twitch fibres
Compare the two types of skeletal muscle fibres in terms of how they generate ATP
fast twitch-Generate ATP through glycolysis only
slow twitch- Rely on aerobic respiration to generate ATP
Compare the two types of skeletal muscle fibres in terms of how much mitochondria they have
fast twitch- Have fewer mitochondria within muscle cells
slow twitch- Have many mitochondria and a high concentration of the oxygen-storing protein myoglobin within muscle cells
Compare the two types of skeletal muscle fibres in terms of blood supply
fast twitch-Have a smaller blood supply (less dense
capillary network supplying muscle cells)
slow twitch- Have a larger blood supply (dense capillary network supplying muscle cells)
Compare the two types of skeletal muscle fibres in terms of storage
Fast twitch- The major storage fuel is glycogen
Slow twitch- The major storage fuel is fats
What is different about athletes muscle tissue
Most human muscle tissue contains a mixture of both fast and slow-twitch muscle fibres. However, athletes dedicated to specific disciplines show distinct patterns of muscle fibres that reflect their sporting activities.
Whats different about athletes who specialise in endurance events
Athletes specialising in endurance events such as long-distance running, cycling or cross-country skiing show a greater proportion of slow-twitch muscle fibres.
Whats different about athletes who specialise in rapid power activities
Athletes specialising in rapid power activities such as sprinting or weightlifting show a greater proportion of fast-twitch muscle fibres.
