Metabolism - SS1 Biology Lesson Note

Metabolism refers to the complex set of chemical reactions that occur within an organism to maintain life. It involves the processes of acquiring, using, and transforming energy and nutrients to carry out various biological functions, including growth, reproduction, response to stimuli, and maintenance of cellular structures. In organisms, there exist two kinds of metabolic activity:

1.     Catabolism: Catabolic reactions involve the breakdown of complex molecules into simpler ones, releasing energy in the process. For example, during cellular respiration, carbohydrates, fats, and proteins are broken down to release energy in the form of ATP (adenosine triphosphate).

2.     Anabolism: Anabolic reactions involve the synthesis of complex molecules from simpler ones, requiring energy

 input. Anabolic processes are responsible for building and maintaining cellular structures and molecules. Examples include protein synthesis, DNA replication, and synthesis of complex carbohydrates.

Enzymes are proteins that help speed up metabolism, or the chemical reactions in cells. They build some substances and break others down. All living things have enzymes. Our bodies naturally produce enzymes. Metabolic reactions are facilitated and regulated by enzymes.

Figure 53 genome.gov

The diagram below shows the feeding habits of an amoeba:

Figure 54 Image from embibe.com