Metabolic Basic


Metabolic Basic For Living 

Metabolic pathway can lead to a more complex structure from a simpler structure ( fro, example, acetic acid becomes cholesterol) or lead to a simpler structure from a complex structure ( for example, glucose, becomes lactic acid in our skeletal muscle). The former cases are called biosynthesis pathways or anabolic pathways. The latter constituent degradation and hence are called catabolic pathways. Anabolic pathways, as expected, consume energy. Assemble of a protein from amino acids requires energy input. On the other hand, catabolic pathways lead to the release of energy. 

For example, when glucose is degraded to lactic acid in our skeletal muscle, energy is liberated. This metabolic pathways from glucose to lactic acid which occurs in 10 metabolic steps is called glycolysis.

Living organisms have learnt to trap this energy liberated during degradation and store it in the form of chemical bonds. As and when needed, this bond energy is utilised for biosynthetic, osmotic and mechanical work that we perform. The most important form of energy currency in living systems is the bond energy in a chemical called adenosine triphosphate ( ATP).

How do living organisms derive their energy?
What strategies have they evolved?

How do they store this energy and in what form?

How do they convert this energy into work?
You wi study and understand a this under a sub_ discipline called ' Bioenergetics' later in your higher classes. 

1) Anabolism:

 Anabolism is the process by which the large, complex chemical compounds,cell organelles and cell products are built up from the small, simpler compounds in the body of a living organism, usually with the use of energy (G.anabole = a raising up; ana= up ➕ bole = a stroke).Because anabolism consumes energy, it is an endergonic process .This energy may be stored in the chemical bonds of the anabolic products__ 

A➕ B➡️AB[ ➕🔼 G].G is Gibbs free energy. Anabolism results in growth and increase in the body weight. It is therefore, also called constructive, or building up, metabolism. Any substance formed as a result of an anabolic process is known as anabolite.

Example: Formation of protein from amino acids

2): Catabolism:

Catabolismis the process by which the large, complex chemical compounds breakdown into  the small, simpler compounds in the body of a living organismoften accompanied by the liberation of energy  (G.katabole = a casting down; kata = down + ballein  = to throw).It is also spelled as katabolism.Beacuse catabolism releases energy, it is an exergonic process ___ AB ➡️A➕B[➖🔼G].This energy may be used in some endergonic  reaction or in some activity, such as movement. Sometimes,  the simpler molecules resulting from catabolism can be used for biosynthesis again. The catabolic products which cannot be transformed by the organism, e.g., CO2,leave the body. Catabolism results in consumption of organic compounds and decrease in the body weight.Catabolism is, therefore,  also called destructive, or breakdown,  metabolism. Any product of catabolism is termed a catabolite.

In may be noted that not every catabolic reaction liberates energy. Some breakdown reactions that the cell performs to eliminate unwanted substances are actually endergonic.

Example: Breakdown of glycogen to carbon dioxide and water.

Stomach               Pancreas

RNA                    Nucleic Acids


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