Define Anaerobic Respiration?

[Anandi]

There are occasions when the cells undergoing respiration cannot get enough oxygen to perform aerobic respiration. For example when exercising vigorously the amount of oxygen getting to the muscles may be insufficient for aerobic respiration. If the cells still require energy then they need to respire without oxygen. This is anaerobic respiration.
Without oxygen the breakdown of the food is incomplete. This means less energy is released. There are two types of anaerobic respiration depending whether it takes place in an animal or a plant / fungi.
Anaerobic Respiration in Animals
In animals, anaerobic respiration produces lactic acid as the glucose is not fully broken down.
Glucose        Lactic acid + energy
If the lactic acid builds up it can stop the muscles from working, causing cramp. This lactic acid needs to be broken down. This requires oxygen. Respiring in this way builds up an oxygen debt which must be repaid in order to get rid of the lactic acid. As a result, animals cannot respire for very long without oxygen.
Anaerobic Respiration in Plants / Fungi
When plants or fungi respire they produce ethanol (alcohol) and carbon dioxide.
Glucose        Carbon Dioxide + Ethanol + energy
A build up of ethanol can be toxic. Some organisms, such as yeast, respire in this way all the time. Yeast is used to make alcoholic drinks. The process is called fermentation.
Yeast is also used in bread making as it gives of carbon dioxide gas which makes the bread rise, giving it a light and fluffy texture.

[Anandi]

Muscle Contraction enables humans to move from place to place and move parts of their body

Synthesis of proteins needed for synthesize enzymes, hormones and antibodies for growth and repair

Active transport absorption of glucose in the small intestine against a concentration gradient requires energy

Passage of nerve impulses to ensure the survival of the human body

Maintenance of a constant body temperature

The heart needs energy to pump blood throughout body
Brain cells need energy for thinking

Lots of energy is also needed in digestion and the processes of excretion

Talking, Breathing
All Body processes requires energy

[John Trivolta]

Respiration is one of the 7 characteristic processes shared by humans.
In aerobic respiration, oxygen is needed, so this must be taken from air by a process of gaseous exchange because carbon dioxide is got rid of at the same time.
The entry of oxygen and exit of carbon dioxide happen at a different place than where energy is released.