METABOLISM AND METABOLIC DISORDERS

 

INTRODUCTION: Thousands of chemical reactions are taking place inside a cell in an organized, well co-ordinated, and purposeful manner; all these reactions are collectively known as Metabolism. The metabolism serves the following purposes:

Purpose 1: Chemical energy is obtained from the degradation of energy rich nutrients including but not limited to carbohydrates and amino acids.  Some of the most common carbohydrates include; Starch, Glucose among others.  

Purpose 2: Food materials are converted into the building block precursors of cellular macromolecules. These building blocks are later made into macromolecules, such as proteins, nucleic acids, polysaccharides, and many others. Biomolecules required for specialized functions of the cell are synthesized.

Purpose 3: Metabolic pathways are taking place with the help of sequential enzyme systems. These pathways are regulated at three levels: 

(i) Regulation through the action of allosteric enzymes, which increase or decrease the activity under the influence of effector molecules. 

(ii) Hormonal regulation. Hormones are chemical messengers secreted by different endocrine glands. 

(iii) Regulation at the DNA level; the concentration of the enzyme is changed by regulation at the level of synthesis of the enzyme.

TYPES OF METABOLIC PATHWAYS:  

Catabolic (degradation) pathways: These are pathways, where energy rich complex macromolecules are degraded into smaller molecules. Energy released during this process is trapped as chemical energy, usually as ATP.

Anabolic (biosynthesis) pathways: The cells synthesize complex molecules from simple precursors. This needs energy.  

Amphibolic pathways: These are seen at cross-roads of metabolism, where both anabolic and catabolic pathways are linked.

RELATED;

1.  STAGES OF METABOLISM

2.  STARCH

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