Organisms obtain energy from thefood they consume. The foodconsumed by the organisms undergo cellular respiration as a result of whichenergy is released. Mitochondria are called power houses of the cells.

Introduction:

Living organisms require energy to carry out various biological processes such as growth, reproduction, and movement. This energy is obtained from the food they consume. The process of obtaining energy from food is known as cellular respiration, which involves the breakdown of complex molecules into simpler forms that can be utilized by cells.

How do living organisms obtain energy from food?

1. Ingestion:
- Living organisms consume food through various methods depending on their feeding habits.
- Animals ingest food through their mouth, while plants absorb nutrients from the soil.

2. Digestion:
- Digestion is the process of breaking down complex food molecules into simpler forms that can be absorbed by cells.
- In animals, digestion occurs in specialized organs such as the stomach and intestines.
- Enzymes secreted by these organs break down carbohydrates, proteins, and fats into smaller molecules.

3. Absorption:
- After digestion, the smaller molecules are absorbed into the bloodstream or cells.
- In animals, nutrients are absorbed through the walls of the small intestine and transported to various body cells.
- In plants, nutrients are absorbed by root hairs and transported through the xylem and phloem to different parts of the plant.

4. Cellular Respiration:
- Once the absorbed nutrients reach the cells, they undergo cellular respiration to release energy.
- Cellular respiration involves a series of chemical reactions that occur in the mitochondria of cells.
- Glucose, a simple sugar derived from carbohydrates, is the primary fuel used for cellular respiration.
- During cellular respiration, glucose is broken down into carbon dioxide and water, releasing energy in the process.

5. ATP Production:
- The energy released during cellular respiration is used to produce ATP (adenosine triphosphate), which is the energy currency of cells.
- ATP is generated through a process called oxidative phosphorylation, which occurs in the inner membrane of mitochondria.
- ATP molecules are then used by cells to carry out various energy-requiring processes.

Conclusion:
- Living organisms obtain energy from food through the processes of ingestion, digestion, absorption, cellular respiration, and ATP production.
- This energy is essential for the survival and functioning of organisms, enabling them to carry out vital biological processes.