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Energy System in Muscle Cells - Coggle Diagram
Energy System in Muscle Cells
Fast-twitch muscle fibres
Few mitochondria
Low blood supply
ATP generated in glycolysis
Low myoglobin concentration
Used for sprinting
Storage fuel is glycogen
Sustained for short periods of time
Contract quickly
Slow-twitch muscle fibres
Used for long distance running
ATP generated in aerobic respiration
Sustained for long periods of time
Many mitochondria
Large blood supply
High myoglobin concentration
Storage fuel is fats
Contracts slowly
Oxygen Debt
During exercise lactate accumulates, causing fatigue
The build-up of lactate produces an oxygen debt
Glycogen reserves become low as glucose is used up in respiration, and some glucose is transported to the liver
After exercise
Once exercise is over, lactic acid must be removed
Lactate is taken to the liver in the blood and is either
Oxidised to carbon dioxide and water
Converted back into pyruvate and glucose, then glycogen - so glycogen levels can be restored
Taking in oxygen to remove lactate and restore the body's reserve of oxygen, is called
repaying the oxygen debt
Lactate Metabolism
When oxygen is present, pyruvate molecules progress into the Citric Acid Cycle
During lots of exercise, oxygen is not available and pyruvate molecules undergo fermentation in the cytoplasm
Hydrogen
ions are
transferred
from
NADH to pyruvate
to produce
lactate
The
removal
of
hydrogen
ions
from NADH regenerates NAD
NAD is needed to maintain ATP production through glycolysis
This only produces 2 ATP, so significantly less than aerobic conditions