The differences between aerobic respiration and anaerobic respiration include where the processes occur, what chemicals are involved in the processes, and what substances are produced by the two processes. Breathing is not respiration. Respiration is a set of chemical reactions that occur in each cell of the body.
Different types of respiration can also depend on the complexity of the organism. Single celled plants and animals do not breathe but they do respire. The same two processes occur regardless of whether an animal lives in the water, on land, or in the air.
The purpose of both aerobic respiration and anaerobic respiration is to produce energy that is in a useable form for the cells of the body. A useable form is a chemical. Both aerobic respiration and anaerobic respiration produce adenosine triphosphate. Adenosine triphosphate has three phosphate radicals. The release of one of the phosphate radicals produces useable energy.
Aerobic respiration requires oxygen and sugar in the form of glucose. Anaerobic respiration creates energy though the breakdown of sugar in the form of glucose.
Aerobic respiration makes 16 times more energy in the form of ATP than aerobic respiration does.
Aerobic respiration releases carbon dioxide, water, and energy. Animals breathe out carbon dioxide that can be used by plants to produce energy. Water from aerobic respiration can be used by the body or excreted. Water is excreted as urine or sweat. Plant cells excrete oxygen.
Anaerobic respiration creates energy and lactic acid. The lactic acid can be a toxin to the body and is removed from the body chemically. Lactic acid build up is one of the reasons a person’s muscles ache after too much exercise. Lactic acid is produced because the anaerobic respiration process does not produce complete combustion of consumption of the glucose molecule.
Anaerobic respiration requires an electron receptor to decompose glucose and produce energy. Anaerobic respiration does occur in the human body. There is a host of microorganisms that do not have access to oxygen. These organisms have adapted to use iron, manganese, uranium, cobalt, sulfur, methane, and several other electron pair receptors to decompose glucose and other sugars to make energy.
How it Works
One of the more economically important products of anaerobic respiration is alcohol for drinking. Yeast breaks down sugar and produce ethanol. This process along with all other fermentation caused by microorganisms is an oxygen-free process. Fermentation in an anaerobic fashion is important for the production of some cheeses.
The cells of the human body can perform aerobic respiration and anaerobic respiration.
Anaerobic respiration takes place in the cells of the muscles and in the red blood cells. The cells know when there is not enough oxygen available to produce the energy required to sustain vigorous physical activity and can use anaerobic respiration to provide the extra energy needed for strenuous work and sports. A person cannot survive on anaerobic respiration alone.
Aerobic respiration is more chemically complex than an anaerobic respiration. Aerobic respiration takes place in portions of the cytoplasm of all cells and in the folds of the mitochondria in all cells. Anaerobic respiration takes place only in the cytoplasm of cells. The added steps in aerobic respiration are the reason aerobic respiration makes more energy than anaerobic respiration.
The first step in each process is called glycolysis. This is the breakdown of glucose. Anaerobic respiration requires the establishment or an electrical gradient across cell boundaries that allow protons to cross the cell boundary in order to use glucose to make energy.
Glycolysis in aerobic respiration requires an energy input from ATP. This energy initiates the decomposition of glucose.
The glucose polymer ring structure is broken apart and further broken down into smaller fragments though the action of an enzyme-like chemical called nicotinamide adenine dinucleotide. The process continues in the presence of oxygen until the fragments that originated from glucose are small enough and chemically structured to pass through the cell wall barrier of the mitochondria.
The fragments of the original glucose molecule undergo further decomposition in the mitochondria in a chemical process called Krebs cycle to produce the majority of the energy that is made in the entire process.
Anaerobic respiration does not require any energy input. Aerobic respiration needs two molecules of ATP to produce the energy needed to break apart the glucose molecule. Anaerobic respiration does not require added chemicals except an electron receptor. Aerobic respiration requires ATP and the enzymes NADH and FADH2 to make the reactions go to completion.
The same two types of respiration can occur in plants. The oxygen for aerobic processes is obtained from carbon dioxide.
What Studies Say
Recent studies of very simple ancient organisms that had the characteristics of both plants and animals have shown that these organisms may have been able to achieve aerobic and anaerobic respiration. The aerobic respiration occurred in folds of the cytoplasm that researchers consider to be the evolutionary ancestors of mitochondria. The organisms most probably used sulfur as an electron receptor in anaerobic respiration because the atmosphere at the time was polluted with volcanic residue that contained sulfur.
Respiration is a chemical process that occurs in plant and animal cells. The type of respiration that occurs is usually dictated by the complexity of the organism’s body.
The need for oxygen is the most fundamental difference between aerobic respiration and anaerobic respiration. The presence of oxygen causes a much higher rate of energy production from a single glucose molecule in aerobic respiration than is seen in anaerobic respiration.
Aerobic respiration is more chemically complex than anaerobic respiration. Aerobic respiration makes more energy because the added chemical steps accomplish the complete breakdown of the glucose molecule.