1.8 - Energy Systems In Muscle Cells Flashcards
Lactate metabolism
What happens to the muscle cells during during vigorous exercise?
During vigorous exercise, the muscle cells do not get sufficient oxygen to support the electron transport stage.
Under these conditions, pyruvate is converted to lactate.
Lactate metabolism - pyruvate being converted into lactate
Under vigorous exercise conditions, pyruvate is converted to lactate which involves the transfer of hydrogen from the NADH produced during glycolysis to pyruvate in order to produce lactate.
This regenerates the NAD needed to maintain ATP production through glycolysis.
Lactate metabolism - oxygen debt repaid
Once the oxygen debt has been repaid, this allows respiration to provide the energy to convert lactate back to pyruvate and glucose in the liver.
Types of skeletal muscle
Skeletal muscles are muscles that are attached to some part of the skeleton and bring about movement of the body.
2 types:
- slow twitch muscle fibres
- fast twitch muscle fibres
Slow twitch muscle fibres - contraction
Slow twitch muscle fibres contract relatively slowly, but can sustain their contractions for longer.
What are slow twitch muscle fibres useful for?
Slow twitch muscle fibres are useful for endurance activities such as long distance running and cycling.
What do slow twitch muscle fibres rely on to generate ATP?
Slow twitch muscle fibres rely on aerobic respiration to generate ATP.
Slow twitch muscle fibres - producing ATP through aerobic respiration
Slow twitch muscle fibres rely on aerobic respiration to generate ATP and have many mitochondria, a large blood supply and a high concentration of the oxygen storing protein MYOGLOBIN.
What is the major storage fuel in slow twitch muscle fibres?
The major storage fuel in slow twitch muscle fibres is fats.
Fast twitch muscle fibres - contraction
Fast twitch muscle fibres contract relatively quickly but can only sustain this over short periods of time.
What are fast twitch muscle fibres useful for
Fast twitch muscle fibres are useful for activities such as sprinting or weightlifting.
Fast twitch muscle fibres - generation of ATP
Fast twitch muscle fibres generate ATP through glycolysis only.
Fast twitch muscle fibres therefore have fewer mitochondria and a lower blood supply compared to slow twitch muscle fibres.
What is the major fuel storage in fast twitch muscle fibres?
The major storage fuel in fast twitch muscle fibres is glycogen. As glycogen stores run low, muscle fatigue occurs.
Muscle tissue in humans
Most human muscle tissue contains a mixture of both slow and fast twitch muscle fibres.
Athletes show distinct patterns of muscle fibres that reflect their sporting activities.
