Aerobic Respiration – The Process of Breaking down of Glucose

0
168
Profile of a relaxed woman breathing fresh air in a green forest

Aerobic respiration is the process of breaking down glucose. Glucose molecules are broken down by means of a series of biochemical transformations, whereby energy in the form of adenosine triphosphate (ATP) and water (H2O) is released.

Glucose consists of six carbon atoms, 12 hydrogen atoms, and six oxygen atoms. It is a type of sugar that is used as an important source of energy in cells. When it enters a cell, glucose will break down to produce pyruvic acid through glycolysis, anaerobic respiration or fermentation depending on various factors including temperature and cellular environment. 

The main reason why glucose cannot be used as a sole source of energy is that hydrogen atoms are lost in the course of its breakdown.

Do you know which of these equations describes aerobic cellular respiration? If not, Check out here!

Adenosine triphosphate (ATP) is a high-energy molecule that is found in cells. It consists of three phosphate groups and is released during respiration. Carbohydrates break down to produce pyruvic acid, which, through enzymatic reactions, is converted into ATP. 

The breakdown has produced the amount of ATP equivalent to about 100 calories (for example: for 1 gm glucose, the equivalent energy will be produced as 100 kcal).

Here some points are discussed about Aerobic Respiration-

1. Anaerobic respiration is an energy.

It is the producing process in which glucose is converted into lactic acid, producing only 2 molecules of ATP per molecule of glucose. In aerobic respiration, oxygen is essential for the conversion of glucose into carbon dioxide and water, thus producing 38 to 40 molecules of ATP per molecule of glucose. 

When oxygen is present, pyruvic acid produced by glycolysis enters the mitochondrion (cell organelle) after passing through the cell membrane and combines with coenzyme A, a compound containing high energy phosphate group(s). Thus, the compound is converted into a molecule of citric acid.

Citric acid is then broken down into two molecules of carbon dioxide, two molecules of water, and two molecules of ATP. Two more phosphate groups are then released from the ATP molecule. The total energy produced by this procedure is 38 to 40 times that obtained from anaerobic respiration (the amount of energy obtained per gram of glucose.)

2. Aerobic respiration occurs in both eukaryotic and prokaryotic cells.

Glucose is simply a molecule of sugar which can be converted into several other simpler molecules, such as lactate, pyruvic acid, and acetyl CoA. The chemical reactions of glycolysis are carried out by an enzyme called hexokinase. 

In eukaryotic cells, glucose is converted to pyruvate at the expense of oxygen with the release of energy in the form of adenosine triphosphate(ATP) and the production of carbon dioxide and water.

In prokaryotic cells, pyruvate is then broken down by a series of reactions to form lactic acid and acetyl coenzyme A (acetyl-CoA). Acetyl-CoA can be further oxidized to produce more energy or enter into the citric acid cycle.

3. Glycolysis is a possible energy source for cells.

It does not require oxygen for processing. Cells that are in an environment with little oxygen or in tissues with oxygen-poor blood often switch from aerobic respiration to glycolysis. In the process, glucose is broken down into pyruvate and produces ATP through anaerobic respiration. 

Pyruvate is then able to pass through a membrane and enters the mitochondrion where aerobic respiration takes place. The major products of glycolysis are pyruvic acid, carbon dioxide, and water.

4. Glycolysis and the citric acid cycle complement each other.

Glycolysis occurs in the cytoplasm of a cell, whereas the citric acid cycle occurs in the mitochondria of a cell. The two processes occur in tandem with one another and use some enzymes from each other. 

Glycolysis cannot produce acetyl-CoA, but it can be converted into acetyl-CoA within a cell by mitochondrial enzymes. In the reverse process, some of the intermediates produced during glycolysis are transported through the mitochondrial membrane to react with Coenzyme A to produce carbon dioxide, water and ATP through oxidative phosphorylation.

5. Glycolysis occurs in the cytoplasm of a cell.

Glycolysis is an anaerobic process that takes place in the cytoplasm of a cell, whereas aerobic respiration (the citric acid cycle) takes place in the mitochondria to produce ATP through oxidative phosphorylation. The two processes occur in tandem with one another and use some enzymes from each other. 

Glycolysis cannot produce acetyl-CoA, but it can be converted into acetyl-CoA within a cell by mitochondrial enzymes. In the reverse process, some of the intermediates produced during glycolysis are transported through the mitochondrial membrane to react with Coenzyme A to produce carbon dioxide, water and ATP through oxidative phosphorylation.

LEAVE A REPLY

Please enter your comment!
Please enter your name here