B2 Aerobic Respiration: temperature, water, plants, energy, contract, proteins, animals, amino, larger,
colder, smaller, birds, mitochondria, day, enzymes, carbon dioxide, oxygen, glucose
Aerobic respiration
Like all chemical reactions respiration is controlled by
enzymes.
Aerobic respiration takes place continuously (day +
night) in both plants and animals.
Glucose + oxygen → carbon dioxide + water (+
energy)
Mitochondria
Most of the reactions of aerobic respiration occur
inside mitochondria found in the cytoplasm of cells.
Uses of energy
Respiration releases energy used to …
1. Build larger molecules from smaller
ones.
2.
Enable muscles to
contract.
3. Maintain a constant body
temperature in colder
surroundings
(mammals + birds)
4. Plants, make amino acids from sugars
and nitrate ions, so that proteins can be
made.
B2 Anaerobic Respiration + exercise: oxygen, carbon dioxide, lactic acid,
rate, liver, oxidise, muscles, depth, circulation , glycogen, heart, blood,
glucose, respiration, exercise, less, aerobic, oxygen debt, water
Anaerobic respiration
During exercise if not enough
oxygen is reaching muscles
they respire anaerobically to
obtain energy.
Glucose → lactic acid (+
energy)
Oxygen debt (HT only)
In anaerobic conditions the
breakdown of glucose is
incomplete. Much less energy
is released than during
aerobic respiration.
Vigorous exercise creates an
oxygen debt. This must be
re-paid after exercise. Extra
oxygen is needed to oxidise
lactic acid …
lactic acid + oxygen → carbon
dioxide + water
Effect of exercise on
muscles
Long periods of vigorous
exercise may cause a build-up
of lactic acid. This can cause
muscles to fatigue, stopping
them from contracting
efficiently.
Massaging muscles helps to
increase blood circulation and
removes lactic acid from
muscles. It is transported to
the liver where it is oxidised
(see oxygen debt).
Effect of exercise on heart and
breathing rates
During exercise heart rate
increases. The rate and depth of
breathing also increases.
These changes increase blood flow
to muscles and so increases the
supply of oxygen and glucose
(sugar) allowing faster rates of
respiration to provide extra energy
needed during exercise.
Increased blood flow also helps to
remove waste carbon dioxide.
Glycogen
Muscles store glucose as
glycogen. During exercise
glycogen is converted into
glucose for use in respiration.
Glycogen →
glucose