Respiration is a process in which the chemical energy in organic food molecules gets released and converted into forms of energy that organisms use to live and thrive on. This process involves the oxidation of food molecules, in which all of them contain the elements involved in photosynthesis (carbon, hydrogen and oxygen). If these elements are then mixed with oxygen, the chemical by-products will then be carbon dioxide and water. This makes up the general equation of aerobic respiration, which goes as follows:
C6H12O6 + O2 = 6CO2 + 6H2O + Energy
Biology. Respiration. N.d. Biology. Biology. Web. 20 Feb. 2012.
In words, this can be expressed as:
Glucose + oxygen = Carbon dioxide + water + energy
In this process, a great amount of energy is released. There can be great damage to an organism if that amount of energy is released all at once. The energy is then released in small 'packets' and they can be used to drive the activities to keep an organism alive. Also, they can be used as a short-term store for energy. The one that is commonly used is ATP.

Aerobic and Anaerobic Respiration

There are two types of respiration, they are simply known as aerobic and anaerobic respiration. Aerobic respiration occurs whenever there is plenty of oxygen is available (this occurs in eukaryotic organisms) and anaerobic respiration occurs whenever little or no oxygen is available (this occurs in prokaryotic organisms).

Gregory, Michael J. Respiration. 2006. Michael J. Gregory, New York. The Biology
Web. Web. 20 Feb. 2012. <
The breaking down of food requires glucose to be burned down during both respiration. As shown in the diagram, there are two ways to respire, that are aerobically and anaerobically. In aerobic respiration, the mitochondria or so called "mini powerhouses" burns down glucose fully for fuel with oxygen and harvest the energy created from this, and transferring it to ATP for use of cell. One cycle of the aerobic process creates a total of 36 ATP molecules. In anaerobic respiration, no oxygen is required, meaning in this process, the mitochondria only uses glucose to burn down for energy, but part of glucose remains. There are two ways to break down glucose, which is through fermentation and lactate. In fermentation, there are yeast which produces alcohol or ethanol, which glucose is broken down to carbon dioxide, ethanol, ATP.
C6H12O6--> 2 C2H5OH + 2 CO2 + Energy
Meanwhile in lactate, glucose is broken down to lactic acid, carbon dioxide and ATP.
C6H12O6--> C3H6O3 + Energy
However, in the end, both methods only creates 2 ATP molecules, which is 34 ATP less than aerobic respiration. Therefore, organisms that use anaerobic are eukaryote such as bacteria since they live deep in the soil or deep underwater where little oxygen is present - which they don't need as much energy.
Berkow, Robert. "Cellular Respiration." Biology. 5 Aug. 2010. Web. 21 Feb. 2012.

How can we measure respiration?
To measure respiration a spirometer can be used. This consists of the person breathing in and out of a mouthpiece connected to a chamber. Inside a chamber there is a piston that moves up and down according to the breathing and records the movements electronically.

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The movements are then shown in a graph called the spirogram. There is a lot of information that can be learnt about the breathing through the spirogram which are the following:
  1. Vital Capacity: is the maximum amount of air breathed after someone breathes the deepest in and out.
  2. Breathing Rate: is just simply the amount of breaths someone takes per minute.
  3. Tidal Volume: is how much a person inhales and exhales after a normal breath.

This is a clear video that explains a spirogram.

Works Cited:
Mitchell, Lea. Lung Capacity Spirogram. You Tube. N.p., n.d. Web. 19 Feb. 2012. <>.
Pickering, W R. "4.2 Breathing ventilates the lungs." Complete Biology . Oxford: Oxford University Press, 2000. 79. Print.