The important basic parts of all cells are:
- Cell membrane
- Cytoplasm
- Nucleus
CELL MEMBRANE
The cell membrane is a biological membrane that separates the interior of all cells from the outside environment. It is also known as the plasma membrane or cytoplasmic membrane. The cytoplasm and nucleus are enclosed within the cell membrane. It forms the wall-like structure between two cells as well as between the cell and its surroundings. It is the living part of the cell.
Structure:
The cell membrane is composed of a phospholipid bilayer with embedded proteins, cholesterol and carbohydrate chains. This structure acts as a semi-permeable barrier, regulating the movement of substances in and out of the cell.
- In the phospholipid bilayer, the hydrophobic tails face inward and the hydrophilic heads face outwards, creating a barrier between the cell’s internal and the external environment.
- The two main types of proteins found in the plasma membrane are integral and peripheral proteins. Integral proteins are embedded within the lipid bilayer. Peripheral proteins are attached to the membrane surface. These proteins help in transport, signaling and structural support.
- Carbohydrates attached to lipids and proteins form glycoproteins and glycolipids which help in cell recognition, adhesion, and signaling.
- Cholesterol helps to regulate its fluidity and stability.
Functions:
The main functions of the cell membrane are:
- It protects the cell and also gives shape to the cell.
- It regulates the entry and exit of substances in the cell. Thus, it is selectively permeable.
- It facilitates the communication with other cells via receptors.
- It regulates exchange of materials with its surroundings.
CYTOPLASM
The cytoplasm is the gel-like transparent substance which fills the cell between nucleus and cell membrane. Cytoplasm is a kind of chemical factory where new substances are built from materials taken into the cell, and energy is released and stored. It consists of cytosol (water + salts + proteins) and various structures of a cell, known as cell organelles. The most important organelle in the cytoplasm is nucleus. Other organelles include mitochondria, ribosomes, golgi bodies, etc. The cytoplasm is about 80% water and usually colourless.
The cytoplasm and the nucleus together form protoplasm.
Functions:
The main functions of the cytoplasm are:
- Most of the chemical reactions of the cell take place in cytoplasm. Thus, it is a site of metabollic reactions.
- It provides a medium for the suspension of organelles and intracellular transport.
- Cytoplasm is responsible for giving a cell its shape.
NUCLEUS