Cell organelles and their functions in a cell are almost similar in all the organisms ranging from microbes to plants and animals.
A cell is an independent system and in some cases it can carry out whole processes as a single living entity like in bacteria, protozoa etc.
A group of cells form a tissue, groups of tissues form an organ, groups of organs form an organism. So cell is a basic element of all the living organisms.
In microbes like amoeba, paramecium, bacteria etc. a single cell even carries out complex functions like eating, digestion, moving, sex, reproduction, excretion etc. through a few extra or modified cell organelles.
In larger animals and plants, this is not present and cells have same set of cell organelles inside.
List of cell organelles in a typical cell:
Cell wall: This is a non-living outer envelope of the cell. This is very characteristic and seen only in plant cells. Even bacteria possess cell wall and hence is classified under plants. It is a rigid, firm, thick external covering of the cell. It is made of cellulose, mucopolysacharides and muco-peptides.
Cell membrane/plasma membrane: This is the outer covering of cell. In plant cells it is present just below the cell wall while in animal cell, it forms the outer most cover. It encloses entire cell and its organelles. It is a selectively permeable, flexible layer of the cell. It is one of the largest organelle in a cell structure.
Cytoplasm: This is the fluid matrix of the cell. It encompasses the cell organelles, other solid substances, water etc. Its volume is fixed and has a definite pH, tonicity depends on the ionic concentration.
Mitochondria: These are sac like organelle which have their own single stranded DNA. Because of this DNA, mitochondria have their own capacity to multiply. Mitochondria structure is sac like.
Golgi bodies: These are the vacuoles or sac like structures. They occupy a considerable amount of cytoplasm.
Endoplasmic reticulum: This is also a sac like structure attached to nucleus and extend thereof like being suspended in the cytoplasm. It is of two types. Rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
Nucleus: This is the inner most and mostly centrally located organelle. It is the control center of the entire cell. They contain the cell’s genetic material. Genetic material: This compromises DNA, chromosomes which assists in cell multiplication.This is the largest organelle inside the cell.
Vesicles: These are small-sized sac like structures. They are of different types lysosomes, peroxisomes. Vacuole: Vacuoles are pouches in the cell that store materials such as water, salts, proteins, and carbohydrates.
Micro-tubules: These are filamentous extensions in cytoplasm. They form the cyto-skeleton.
Cell organelles and their functions include:
Each cell organelle has a specific role to play in the cell’s physiology and growth.
Cell wall: Since plants are mostly non-motile, cell wall presence imparts rigidity, capacity to tolerate harsh conditions like wind, heat, wear and tear etc. It imparts definite shape to cell.
Cell membrane: This is a selectively permeable membrane and hence helps transport of desired substances into and outside the cell. In animal cells, the membrane is flexible and helps tolerate mechanical movements. It is made of glycoproteins, glycolipids etc.
Mitochondria: The main function of mitochondria is to generate energy. They provide energy for all cellular functions by utilization of glucose and oxygen.
Endoplasmic reticulum: This is of two types rough and smooth types. Smooth ER helps in formation of lipids where as Rough ER helps in formation of proteins.
Nucleus function: This is the key organelle which has the genetic material and is involved in multiplication of cell, growth and maintenance of cell. This nucleus is absent in prokaryotic cells.
Golgi bodies: They are helpful in storage and transport of substances in the cell.
Vesicles: These help in storage and release of substances as required by the cell. For example lysosomes help in cell digestion when cell dies. Vacuoles function is to store water.
Micro-tubules: These micro-tubules provide structural strength. Because of these micro-tubules, the cell has a fixed structure and does not collapse.