Name: Biodiversity and Megadiversity
Uploaded: 2019-07-19
Duration: 6 min 1 s
Description: Every day we come across so many types of living beings. Have you ever wondered how many different types of species are there in total? Watch this video.

Question

What are cell organelles? Name the various cell organelles and list their functions.

Accepted Answer

The various microscopic structures present inside a cell that take part in the proper functioning of a cell are called cell organelles. The major organelles are as follows:

Mitochondria: These are the membrane-enclosed organelle found in the cytoplasm of all eukaryotic cells. These are generally described as the powerhouse of the cell or cellular power plants as they generate most of the cell's supply of ATP. It is the site of cellular respiration.

Plastids: These are the major organelle found in plants including algae. These are double membranous organelles with their own DNA and are responsible for synthesis of food, storage of starch, etc. Chloroplast is the site of photosynthesis that bear chlorophyll pigment.

Ribosome: The ribosome is the non-membranous organelle present in both eukaryotic and prokaryotic cells. It is the smallest cell organelle that is the centre of protein synthesis. It is chemically composed of ribosomal RNA (rRNA) and various types of protein.

Endoplasmic reticulum: ER is the double membrane-bound organelle which is the largest internal membrane system in the cytoplasm of the cell. It is of two types on the basis of the presence of ribosomes. Endoplasmic reticulum which possesses ribosome called as rough endoplasmic reticulum (RER) and without ribosome is called smooth endoplasmic reticulum (SER). The RER is responsible for the manufacturing and transport of membrane-bound and secretory proteins. The SER engaged in producing a lot of lipids, vitamins, carbohydrates, steroid hormones and also in the process of detoxification of the cell.

Golgi complex: It refers to stacks of single membrane-bound vesicle that is composed of sacs known as cisternae or saccules, tubules and vesicles. It is important in packaging macromolecules for transport to elsewhere in the cell and out of the cell.

Lysosomes: These are the single membrane-bound cell organelles that are is responsible for the controlled intracellular digestion of macromolecules. It is the principal site of cholesterol assimilation.

Vacuoles: These are the non-cytoplasmic areas bounded by a single membrane bilayer present in the cytoplasm. Large vacuoles are characteristic of matured plant cells. It contains digestive enzymes and various dissolved minerals. Secondary metabolites like tannin, latex, etc., are stored in vacuoles.

Microtubules: These are thin, branched, hollow cylinder. Most commonly each microtubule is composed of a ring of longitudinal strands of protein protofilaments. The protofilaments are made up of a protein called tubulin. These constitute the axoneme of cilia and flagella. These constitute the mitotic spindle responsible for the movement of chromosomes during cell division. These also synthesis the cell plate during cytokinesis.

Peroxisomes: These are a kind of microbodies present in almost all eukaryotic cells. It is a single membrane-bound vesicle. It is a major site of oxygen utilisation.

Nucleus: It is a double-membrane enclosed organelle found in most eukaryotic cells. It contains most of the genetic materials. The nucleus consists of an outer double-layered nuclear envelope, nuclear sap, chromatin and nucleolus.

What are cell organelles? Name the various cell organelles and list their functions.

Important Questions on Cell - Structure and Functions

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