Cell and Energy Cycle Preparation and Properties
→ The Cell : Body of animals and plants are made up of very small cells which are baisc units of life. Cell is the structural and functional unit of life which is discovered by Robert Hook in 1665. Normaly, cells seen by the help of microscope. Essential substances for living body are stored and used by these cells. Living cells has the speciality for dividing the cells in to unit cells. These process are done in a cycle.
A simple Animal cells are divided in to three parts
- Cell membrane
→ Cell membrane : Each cell contains selectively permeable and electrical charged membrane around cytoplasm which is known as cell membrane or plasma membrane. It helps in transportation of chemical substances. It is a double membrane formed by proteins and fats.
→ Cytoplasm : The material or protoplasm within a living cell, excluding the nucleus is called cytoplasm. Cytoplasm is the site of many biochemical reactions that are vital and crucial for maintaining life. The cytoplasm is a means of transport for genetic material. Various cell organdies like mitochondria, ribosomes. lysoso mes, Golgi Bodies etc, are present in cytoplasm.
→ Nucleus : Nucleus controls the cell’s growth and reproduction in living body. It is also known as command centre of our body. It was discovered by Robert Brown in 1831. In mammals, nucleus is present in all cells, except red blood cells. It is surrounded by double layer of proteins.
→ Energy Cycle : Energy is required for growth, maintenance and development of living organism. Also energy is required for mechanical work, various chemical reactions taking place in body and for transport of molecules. This energy is obtained by degradation of food molecules. Living organism also synthesize various types of molecules.
→ The energy obtained by degradation of food molecules is utilised in synthesising these molecules. All thsese reactions takes place inside the cell. All the reactions taking place in the living organismswhich produces or utilises energy are called metabolic reactions.
Metabolic reactions can be classified into two parts :
- Anabolism and
→ Anabolism : The chemical reactions by which the micromolecules are synthesized in the cell are called anabolism. It is a constructive process. It is a constructiveprous. The synthesis of complex molecules in living organisms from simpler ones together with the storage of energy takes place by anabolism. These reactions require energy, and also known as an endergonic process.
→ Catabolism : It is destructive process. A metabolic process in which complex molecules are broken down into simple ones with the release of energy is called catabolism. Catabolism and anabolism takes place simultaneously and related to each other. For example, synthesis of protein from amino acids is a anabolic process whereas conversion of carbohydrate into carbon dioxide and water is a catabolic process.
→ Cells obtained energy by oxidation of food. This oxidation generally takes place in mitochondria present the cell in the presence of enzymes. Therefore, Mitochondria is also known as power house of the cell.
→ Some of the energy obtained by oxidation of food is used in the formation of ATP molecules. These acts as energy sources for other processes taking place in the body.
→ Carbohydrates proteins and fats are main sources of energy. Among them oxidation of glucose is very important. The oxidation of glucose takes place inside the cell in the presence of air and energy is releases.
→ Oxidation of glucose can be represented by foliwoing process :
→ Carbohydrates are synthesized in the green parts of the plants by the process of photosynthesis as follows :
→ Some part of this energy is used by the cell and some part is stored in the form of ATP. The complete process of oxidation of glucose can be represented as:
C6H12O6 + 36ADP + 36H3 PO4 + 6O2 → 6CO2 + 42H2O + 36 ATP