Metabolism is the term used to describe all the chemical reactions that take place inside living cells to maintain life.
These reactions help organisms grow, reproduce, repair damage, and obtain energy from food.
1. Definition
Metabolism is the sum of all biochemical reactions that occur in an organism to convert food and nutrients into energy and building materials needed for life.
It involves two main types of processes:
2. Types of Metabolism
(a) Catabolism
- Catabolism is the breakdown of large molecules (like carbohydrates, fats, and proteins) into smaller ones.
- These reactions release energy, which is stored as ATP (Adenosine Triphosphate).
- Example: Breaking down glucose during cellular respiration to produce energy.
(b) Anabolism
- Anabolism is the building up of complex molecules from smaller ones.
- These reactions use energy (usually from ATP) to build cell structures, enzymes, proteins, and DNA.
- Example: Formation of proteins from amino acids or DNA from nucleotides.
3. Importance of Metabolism
1. Energy Production
- Metabolism provides energy for all cell activities, such as movement, growth, and repair.
- Without metabolic energy, cells would not survive.
2. Building Cellular Components
- Anabolic reactions produce important molecules like proteins, lipids, and nucleic acids needed for cell structure and function.
3. Maintenance and Repair
- Metabolic reactions help replace damaged cell parts and maintain normal cellular functions.
4. Regulation and Balance
- Metabolism maintains homeostasis, meaning a stable internal environment.
- It balances energy intake and energy use in the body.
5. Waste Removal
- Catabolic processes produce waste products (like carbon dioxide, water, and urea), which are removed from the body.
6. Adaptation
- Metabolism adjusts according to the organism’s environment, food supply, and energy needs.
4. Example of Metabolic Pathways
- Glycolysis: Breaks down glucose into pyruvate to release energy.
- Krebs Cycle: Produces ATP and electron carriers.
- Photosynthesis (in plants): Converts sunlight into chemical energy (stored as glucose).
In short:
Metabolism is the chemical engine of life.
It includes all the reactions that break down food to release energy (catabolism) and build up new molecules (anabolism).
It is important because it provides energy, materials, and balance needed for growth, repair, and survival of all living organisms.