Metabolism

Metabolism is the sum of all the chemical reactions occurring within a cell or the body. These reactions are essential for life, as they help synthesize and break down molecules needed for growth, energy, and repair.

The energy released by respiration in cells powers the enzyme-controlled processes that drive metabolism, enabling the continuous synthesis of new molecules.

Key metabolic processes

Metabolism includes several essential processes, such as:

1. Conversion of Glucose: Glucose can be converted into starch, glycogen, and cellulose for storage and structural purposes (covered in Topic 2 and Topic 4).

2. Formation of Lipids: Lipid molecules are made from one molecule of glycerol combined with three molecules of fatty acids. This is crucial for creating fats and oils in the body (Topic 2).

3. Protein Synthesis: Glucose and nitrate ions are used to form amino acids, which then join together to make proteins—vital for growth and repair (Topic 2 and Topic 4).

4. Respiration: Both aerobic and anaerobic respiration are part of metabolism, providing the energy required for these cellular reactions (Topic 4).

5. Breakdown of Excess Proteins: Extra proteins are broken down into urea for excretion, which is then removed from the body through urine (Topic 1 and Topic 5).

Each of these processes plays a significant role in maintaining the body's functions and is explored in greater detail in the relevant sections of the curriculum.

Importance of key molecules