The cell organelles and their functions are essential for the independent life of a cell.
List of cell organelles in a typical cell
- The cell membrane (plasma membrane)
- Golgi Apparatus
- Endoplasmic reticulum
- Centrosome (Centrioles)
Due to its organelles, a cell carries out most physiological processes, like respiration, reproduction, and excretion, on its own.
But we can still say that a cell is an independent entity and makes up the whole living system in the world.
A group of cells forms a tissue, groups of tissues form an organ, and groups of organs form an organism. So the cell is a basic element of all living organisms.
Check Out: List Of Cells in Human Body
A typical cell, as shown in the image below
Cell membrane/ Plasma membrane
The cell membrane is the outer covering of the cell.
In-plant cells, it is seen just below the cell wall, while in an animal cell, it forms the outermost cover.
It is a lipid bilayer of cholesterol, phospholipids, proteins, and carbohydrates. It encloses the entire cell and its organelles.
It is a selectively permeable, flexible layer of the cell.
It is one of the largest organelles in a cell structure.
Cell membrane: This is a selectively permeable membrane that helps transport 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.
This is the innermost and most centrally located organelle.
The nucleus’s function is to regulate the activities of the entire cell. Hence it is called the control center of the cell.
They contain the cell’s genetic material.
This is the key organelle with the genetic material and is involved in the multiplication of cells, growth, and maintenance of cells.
This nucleus is absent in prokaryotic cells. The nucleus has a nucleolus that produces ribosomes.
These ribosomes pass out of the nucleus and settle over the endoplasmic reticulum to aid protein synthesis by translation.
These are the energy-generating organs of the cells where cellular respiration takes place.
They have a sac-like structure and are made of two membranes.
A typical mitochondrion has 4 major parts like
- Outer membrane
- Inner membrane
- Matrix (i.e., the mass inside the inner membrane)
The inner membranous space is helpful for oxidative phosphorylation to generate ATP.
Mitochondria have their own single-stranded DNA and hence they can self-replicate.
Hence mitochondria multiply within the cell even before a cell divides.
This is because they are worn out during the process of cell respiration.
So, they form new ones to carry out the function non-stop. Check for its structure Mitochondria structure.
The Golgi bodies are the vacuoles or sac-like structures that occupy a considerable amount of cytoplasm.
They are formed from the endoplasmic reticulum.
They have two sets of vesicles as Cis and Trans Golgi networks. Cis-set is at the center, while the trans set is at the periphery of the apparatus.
From these vesicles, lysosomes are formed.
They are helpful in the storage and transport of substances in the cell.
This is also a sac-like structure attached to the nucleus and extends thereof, like being suspended in the cytoplasm.
It is of two types: rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
These are filamentous extensions in the cytoplasm. They form the cytoskeleton.
These micro-tubules provide structural strength.
Because of these microtubules, the cell has a fixed structure and does not collapse.
The is a major microtubule and has centrioles that form spindles and help separate genetic material during the cell division.
Lysosomes are cell organelles found mostly bound to the cell membrane.
This organelle is found in all cells and contains hydrolytic enzymes.
Lysosomes break down and recycle worn-out cells.
The lysosomal enzymes digest the cell contents and remove the waste matter.
They are called suicidal bags of cells and play a larger role in cell physiology and organisms’ life.
For more details, see the importance of lysosomes.
These are vesicles that store enzymes of energy metabolism.
These are the organelles of locomotion. They are found in a few cells like protozoans and human cell sperms.
These are the organelles that help in the movement of a particle near the membrane on the outer surface.
This compromises DNA and chromosomes, which assist in cell multiplication.
This is not an organelle but is present in the nucleus and involves cell multiplication.
These are small-sized sac-like structures. They are different types of lysosomes and peroxisomes.
These help in the storage and transport of substances as required by the cell.
Vacuoles are pouches in the cell cytoplasm that store materials such as water, salts, proteins, and carbohydrates.
This is not an organelle but a fluid matrix of the cell.
It encompasses cell organelles, other solid substances, enzymes, water, etc.
Its volume is fixed and has a definite pH; tonicity depends on the ionic concentration.
This is a non-living outer envelope of the cell. This is very characteristic and is seen only in plant cells.
Even bacteria possess cell walls and hence are sometimes classified under plants.
It is a rigid, firm, thick external covering of the cell. It is made of cellulose, mucopolysaccharides and muco-peptides.
Cell wall function: Since plants are mostly non-motile, cell wall presence imparts rigidity and capacity to tolerate harsh conditions like wind, heat, wear and tear, etc. It imparts a definite shape to the cell.
Specialized cell organelles
These are the cell organelles present in cells of special purpose. These include
These organelles are present in leaf cells and green algae.
These chloroplasts contain chlorophyll pigment that helps in photosynthesis. So, chloroplasts are the site of photosynthesis. This is a process that captures energy from sunlight and stores it as carbohydrates forming food.
These are the organs present in bacteria. The small tubular structures anchor out of the cell. They are meant for sexual reproduction.
These are the organelles that see only a few types of bacteria. They are hair-like structures helping in motion.
Seen in euglena (protozoa) and a few algae. It helps detect the sunlight and move the cell toward the light.
Also, one comes across these cell organelles in botany.
There are small differences in cell organelles and their function between animal and plant cells.
But largely similar. On the other hand, most of the organelles are absent in red blood cells.
Frequently asked questions
Which Cell Organelles contain DNA
Mitochondria is an organelle that has DNA.
The DNA is present in the nucleus and also mitochondria. The difference is that the nucleus has whole-genome DNA, while mitochondria have smaller circular DNA.
Which cell organelles have a double membrane
The plasma membrane, nucleus, and mitochondria are the cell organelles that have clear-cut double-membrane structures.
What organelle controls a cell’s packaging storage and shipping functions
Golgi bodies are organelles involved in packaging, storage, and shipping functions.
Are red blood cells eukaryotic or prokaryotic?
Red blood cells are called corpuscles because these are cells devoid of nuclei and genetic material.
Unlike eukaryotes and prokaryotes, they do not undergo cell division and lack cell cycle too.
But since they have nuclei in the premature form (erythroblasts) and are formed from eukaryotes, they can be considered as eukaryotes.
- Essential Cell biology-Bruce Alberts.