Cytoplasm

 Cytoplasm Structure and Function

What is the Cytoplasm?

The cytoplasm is a region between the nuclear membrane and the cell membrane. It is a combination of two words i.e. Cyto means cell and Plasm means fluid or liquid. 

The cytoplasm was discovered by George E Palade, Albert Claude and Christian de Duve in 1835 after the discovery of the cells by Robert Hooke in 1831. Rudolph von Killer first used the term cytoplasm in 1863.

Cytoplasm Composition

The cytoplasm is made up of the following main components;

• Cytosol
• OrganelleS
• Cytoplasmic inclusions

Cytosol

The cytosol is the liquid portion of the cytoplasm. It has a colorless and jelly-like appearance. It is composed of 70% of water and 30% of other substances.

The cytosol has two types i.e. true solution and colloidal solution.

1. True solution: The true solution contains ions such as calcium, magnesium, potassium, chloride, bicarbonates, etc. and small molecules such as oxygen, carbon dioxide, glucose, amino acids, etc.  
2. Colloidal solution: the colloidal solution contains large molecules such as proteins, lipids, carbohydrates, etc. It is further divided into two parts. The sol part is towards the inside and is less viscous and the gel part is peripheral and more viscous.

Organelles

There are many organelles in the cell that float on the surface of the cytoplasm and perform their specific functions. These are the nucleus, endoplasmic reticulum, Golgi bodies, mitochondria, lysosomes, peroxisomes, and ribosomes.  

Cytoplasmic Inclusions

The cytoplasmic inclusions include non-membranous parts such as nutrients, pigment and secretory products.

  

Cytoplasm Functions

1. Cytoplasm is a highly organized structure that helps the cytoskeleton maintain the shape of cells and provide support to the cells.
2. It serves as a site for the organelles which can float and perform their functions easily.
3. It provides all the important components required for all metabolic activities of the cell.
4. It allows the molecules or ions to come inside the cell and move outside the cell.
5. It also plays an important role in cell signaling transduction by sending messages received from membrane receptors to the nucleus and other specific organelles.
6. Almost all the important metabolic activities occur in the cytoplasm. These are;  

•    Glycolysis which is the breakdown of glucose molecules.
•    Glyconeogenesis which is the formation of glucose molecules from carbohydrate sources like         pyruvate, glycerol and protein sources such as amino acids.
•    Glycogenolysis which is the breakdown of glycogen molecules.
•    Protein synthesis that is the formation of protein molecules on ribosomes. 
•    Cell division that is the formation of two daughter cells from a single cell.
•    ATP synthesis by providing ADP and inorganic phosphates to the mitochondria.