Unit 1 KA8 - energy system in muscle cells

Question 1

describe lactate metabolism.

Answer 1

during vigorous exercise, the muscle cells do not get sufficient oxygen to support the electron transport chain.
pyruvate is converted to lactate under these conditions.
this conversion involves the transfer of hydrogen ions 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 accumulates and causes muscle fatigue.

Question 2

what are the two categories of skeletal muscle fibres?

Answer 2

fast-twitch and slow-twitch.

Question 3

describe qualities of slow-twitch muscle fibres.

Answer 3

good for endurance activities.
contract slowly but can sustain contractions for longer.
rely on aerobic respiration to generate ATP.

Question 4

describe qualities of fast-twitch muscle fibers.

Answer 4

good for sprinting, weightlifting.
contract quickly but can only sustain contractions for short periods of time.
can generate ATP through glycolysis only.

Question 5

what do slow-twitch muscle fibres have?

Answer 5

many mitochondria, large blood supply, high concentration of the oxygen storing protein myoglobin, major storage fuel is fats.

Question 6

what do fast-twitch muscle fibres have?

Answer 6

few mitochondria, lower blood supply, major storage fuel is glycogen.

Question 7

the oxygen ……. is repaid when exercise comes to a halt, which allows ……….. to provide the ……… to convert ………. back to………… and…………in the ………..

Answer 7

debt, respiration, energy, lactate, pyruvate, glucose, liver.