energy systems in muscle cells 1.8

Question 1

what happens to muscle cells during exercise

Answer 1

they do not get a sufficient supply of oxygen to support an increase rate of aerobic respiration (electron transport chain)

Question 2

lactate metabolism

Answer 2

-when muscle cells don’t have enough oxygen the cells start to respire anaerobically and pyruvate is converted to lactate
-this conversion involves the transfer of hydrogen to pyruvate from the NADH produced during glycolysis in order for pyruvate to produce lactate
-this regenerates NAD needed to maintain ATP production through glycolysis
-lactate accumulates in muscle cells causing muscle fatigue and oxygen dept builds up
-the oxygen dept is repaid when exercise stops
-this allows respiration to provide energy to convert lactate back to pyruvate and glucose in the liver

Question 3

skeletal muscle fibres

Answer 3

brings about the movement of the body during physical activity

Question 4

the two types of sketetal muscle fibres

Answer 4

slow twitch muscle fibres and fast twitch muscle fibres

Question 5

slow twitch muscle fibres

Answer 5

-contract relatively slow
-contraction is sustained for longer periods of time
-useful for endurance activities such as long distance running and cycling
-rely on aerobic respiration to generate ATP
-many mitochondria
-large blood supply
-high concentration of myoglobin (oxygen storing protein) in cells
-major storage fuel is fats

Question 6

fast twitch muscle fibres

Answer 6

-contract relatively quick
-contraction is sustained for a short period of time
-useful for short bursts of activity such as sprinting and weight lifting
-can generate ATP using glycolysis
-fewer mitochondria
-lower blood supply
-low concentration of myoglobin in cells
-major storage fuel in glycogen