Respiration: The breakdown of food molecules to release energy is called respiration. Usually cells use oxygen to oxide food. It results and water as waste products. The main food oxidized is the sugar i.e. Glucose. The overall equation for this chemical reaction is:
Above equation shows that one molecule of glucose reacts with six molecules of oxygen to produce six molecules of carbon dioxide and six molecules of water. The main product is energy which is produced in the form of energy rich molecules called ATP.
Difference between breathing and respiration:
All the life process cells requires energy. The source of this energy is food or photo assimilates (Products of photosynthesis) in plants.
There are two types of respiration found in living organisms for the production of energy.
Anaerobic Respiration or Fermentation
Aerobic Respiration
1) Anaerobic Respiration:
The primitive type of respiration which takes place in the absence of or without is called anaerobic respiration or fermentation. There are 2 special conditions where is not available so the organisms adapt themselves to break down their food without oxygen which is called anaerobic respiration or fermentation. It takes place in some bacteria, fungi, endoparasite and sometimes in animal.
Benefits of anaerobic respiration: During anaerobic respiration, glucose is not broken down completely so less amount of energy (5 to 10% as compared to aerobic respiration) is released but it can sustain life even in the absence of . It had evolved on earth where there was no on earth.
There are two types of anaerobic respiration.
i) Alcoholic fermentation: The bacteria and fungi respire aerobically but when these organisms are deprived of oxygen they stop respiration aerobically and start respiring anaerobically instead, During this anaerobic respiration they produce ethyl alcohol with .
ii) Acidic fermentation: In animals when aerobic respiration is not enough to produced required energy they start anaerobic respiration. During this process glucose breaks down into a substance called lactic acid.
A limited amount of energy is produced as compared to aerobic respiration but this is enough to power the athlete's muscles during start time of sprint. He experiences pain, this condition of pain is called Muscle fatigue. The lactic acid is produced in his muscles and bool stream.
Importance of anaerobic respiration:
Emergency arrangement of energy: Anaerobic respiration is the emergency arrangement of energy which has an advantage that organisms can survive without or can work for short period with same pace.
Commercial production of acids: The other products of anaerobic respiration are acids. Vinegars are also organic acids that are produced commercially by acidic formulations.
Commercial production of alcoholic products: Anaerobic respiration also produces ethyl alcohol. This process is commercially utilized by making alcoholic products like beer, wines and other beverages.
Baking industry: Baking industry is also based on it because anaerobic respiration also produces which gives fluffy and soft shapes to cakes and breads also break down of starch into complex sugar to form bread and pizza.
2) Aerobic Respiration:
Type of respiration where food breakdown occurs in the presence of oxygen to produce energy. It is a method of respiration found in majority of organisms. It takes place in the presence of free oxygen, oxidizing the food and releasing the maximum amount of energy i.e. 2827 kj / mole of glucose or 36 ATP molecules/glucose. The end products of aerobic respiration are and .
Aerobic Respiration takes place in 3 steps at different places in the cell.
a) Glycolysis
b) Kreb’s Cycle or Citric Acid Cycle
c) Electron Transport Chain
(a) Glycolysis (Gr. Glyco = Sugar, Lysis = Break down):
First stage is that stage where a molecule of glucose (Six carbon sugar) is broken down into two molecules of pyruvic acid (three carbon acid).
It does not require oxygen.
It takes place in both aerobic and anaerobic respiration.
This splitting of glucose releases small amount of energy of glucose which is enough to generate 2 molecules of ATP.
Glycolysis is a complex sequence of reactions, all of them occur in cytosol.
(b) Kreb's or Citric acid Cycle:
The second stage of aerobic respiration in which pyruvic acid produced during glycolysis enters the mitochondria where available.
Cellular respiration uses this to break pyruvic acid completely into and in a cyclic manner.
During Kreb's Cycle some ATP produce and some coenzymes like NAD and FAD are reduced to and .
It takes place in matrix of mitochondria.
(c) Electron Transport Chain:
The last stage of aerobic respiration in which (Nicotinamide 2 Adenosine Di-nucleotide) and (Flavinamide Adenosine Dinucleotide) are oxidized to produce ATP and .
It takes place at the cristae of mitochondria.
Number of Processes requires energy in the body of an organism. Body provides it from respiratory energy. Following are some process which utilize respiratory energy.
Synthesis of molecules - Formation of different molecules as well as large molecules from small molecules requires energy.
Cell division - During cell division formation of large molecules like DNA and protein takes place which require energy as well as movement of chromosome also require energy.
Growth without cell division - enlargement growth is not possible and both require formation of molecules which require energy.
Active transport - movement of ions and molecules from low concentration to high concentration requires energy.
Muscle Contraction - Movement of muscle requires energy which is produced from chemical energy, chemical energy converted into kinetic energy.
Passage of Nerve impulse - Nerve Impulse (message of Neuron) is basically electrical signals moving long nerve fiber by active transport requires energy.
Maintenance of Body temperature - In higher animal's body temperature is maintained at constant level, this temperature maintenance requires energy of respiration.
