All living cells need energy to stay alive. Respiration is a
chemical reaction that occurs in all living cells to produce
There are two types of respiration:
Aerobic respiration can only occur in the presence of oxygen.
Oxygen taken in from the air combines with the glucose take
from food. The two combined produce carbon dioxide, water
and energy is released as well.
Respiration occurs in a part of the cell called the mitochondria.
GLUCOSE + OXYGEN -> CARBON DIOXIDE +
WATER + (energy)
Anaerobic respiration occurs when there is not enough oxygen.
In humans a common situation is during exercise when the
oxygen supply is less than the demand from the cells. Therefore
the cells have to use anaerobic respiration to get the energy.
However you do not get the same products. Anaerobic
respiration produces a substance called lactic acid.
GLUCOSE -> LACTIC ACID + (energy)
Anaerobic respiration can also be used to make alcohol. This
reaction occurs in microorganisms such as bacteria and yeast,
which use glucose to form carbon dioxide and ethanol. This
process is known as fermentation.
GLUCOSE -> ETHANOL + CARBON DIOXIDE