Book : Cell Biology
Posted by: CHELSEA
Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. In eukaryotic cells, the cytoplasm includes all of the material inside the cell and outside of the nucleus. All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm. The portion of the cytoplasm that is not contained in the organelles is called the cytosol. Although cytoplasm may appear to have no form or structure, it is actually highly organized. A framework of protein scaffolds called the cytoskeleton provides the cytoplasm and the cell with their structure. The cytoplasm is made of 70% - 90% water and is colorless usually. Most of the cellular activities occur in the cytoplasm. Metabolic pathways like glycolysis and cellular processes like cell division take place in the cytoplasm. The outer clear and glassy layer of the cytoplasm is called the ectoplasm or the cell cortex and the inner granular mass is called the endoplasm. In plants cells, a process known as cytoplasmic streaming takes place where there are movements of the cytoplasm around the vacuoles.
Characteristics of Cytoplasm:
- ¬ Cytoplasm is the fluid substance that fills the space between the cell membrane and the cellular organelles.
- ¬ Cytoplasm shows differential staining properties, the areas stained with the basic dyes are the basophilic areas of the cytoplasm and is termed as ergatoplasm for this material.
- ¬ It is heterogenous mixture of opaque granules and organic compounds which gives it its colloidal nature.
- ¬ The peripheral zone of cytoplasm is thick and jelly-like substance, known as the plasmogel. The surrounding area of the nuclear zone is thin and liquefied in nature and is known as the plasmosol.
- ¬ The physical nature of cytoplasm is colloidal. It has a high percentage of water and particles of various shapes and sizes are suspended in it.
- ¬ It also contains proteins, of which 20-25 percent are soluble proteins including enzymes.
- ¬ Also, certain amount of carbohydrates, inorganic salts, lipids and lipoidal substances are found.
- ¬ The plasmogel part of the cytoplasm is capable of absorbing water and removing it, according to the cells need.
- ¬ The stomatal guard cell presents in the leaves exhibit this property.
- ¬ An organized system of fibrers can be observed by specific staining techniques.
- ¬ Chemically cytoplasm contains 90% water and 10% include a mixture of organic and inorganic compounds in various proportions.
Function of Cytoplasm:
- ¬ The jelly-like fluid that fills a cell is called cytoplasm. It is made up of mostly water and salt. Cytoplasm is present within the cell membrane of all cell types and contains all organelles and cell parts. Cytoplasm has various functions in the cell.
- ¬ Most of the important activities of the cell occur in the cytoplasm. Cytoplasm contains molecules such as enzymes which are responsible for breaking down waste and also aid in metabolic activity.
- ¬ Cytoplasm is responsible for giving a cell its shape. It helps to fill out the cell and keeps organelles in their place. Without cytoplasm, the cell would be deflated and materials would not be able to pass easily from one organelle to another.
- Cytosol is the part of the cytoplasm that does not contain organelles. Instead, cytosol is confined by the boundaries of a matrix which fills the part of the cell that does not contain organelles.