Cell Organelles – Definition, Structure, Function
All species on our planet are composed of millions of cell organelles, each performing different types of functions, while also playing an active role in the growth of said species. Although the type of cells differs from each other based on their functions or type of species, the components, as well as structure, have similar functions. And here in the article below, we will talk about the Cell Organelles, Their Functions, Structures, and many more.
What are Cell Organelles?
A subcellular structure inside a cell that has a specific function to perform. Moreover, cell organelles are of different types, such as Organelles without Membrane, Single Membrane-Bound Organelles, and Double Membrane-Bound Organelles. These types of cells essentially communicate with each other, to make sure all the functions are performed correctly based on the type of organism or species.
Types of Cell Organelles
The types of cell organelles are given below,
- Organelles without Membrane – These types of cell organelles are found in both eukaryotic as well as prokaryotic cells. Ribosomes, cytoskeletons, and Cell walls are some popular examples of Organelles without membranes.
- Single Membrane-Bound Organelles – Unlike the above-mentioned cells, this type of cell is only found in eukaryotic cells. Some examples of Single Membrane-Bound Organelles are the Endoplasmic Reticulum, Vacuole, Golgi Apparatus, Lysosome, etc.
- Double Membrane-Bound Organelles – Chloroplast, Nucleus, and Mitochondria, are the common examples of Double Membrane-Bound Organelles, that are actively observed in eukaryotic cells.
Cell Organelles Diagram
In the above diagram, you can see the different components of the Cell Organelles and their respective location inside the cell.
Functions of Cell Organelles – As per the list of cell organelles
As depicted in the above diagram, all the cell organelles have different types of functions in the cell, which we are going to discuss briefly here in this section. Let us record the list of cell organelles and individually analyze the functions of cell organelles
Cell Membrane/ Plasma Membrane
The foremost in the list of cell organelles, this is present in both plant cells as well as animal cells. Their permeability is selective wherein they materials into and out of the cell as per the needs of the cell. These membranes are made of a bilipid layer and protein and they enclose the cell contents while defining and offering shape in the case of an animal cell. Their function also includes Diffusion and Osmosis.
Cell Wall
Cell walls for the cell organelles are seen only in plant cells and are hard and rigid, with full permeability. They are made of cellulose in plants and provide key and basic protection, while also giving shape and turgidity.
Cytoplasm
As we delve deeper into the functions of cell organelles, the cytoplasm or the jelly-like substance, which is located between the nucleus and cell membrane, becomes most prominent in the list of cell organelles. The main function of these components is to control and manage all the metabolic activities inside the cell, because of the presence of the enzymes in it. Moreover, the cytoplasm is made up of organic, and inorganic compounds, and water.
Nucleus
The nucleus is said to be the largest membrane-bound organelles, whose function is controlling the activity of cells, and various other processes such as storing and managing the hereditary characters, as well as the division of cells. Furthermore, to control hereditary characteristics, this component stores all the genetic information.
As we have learned, the nucleus, or the double-membraned organelle found in all eukaryotic cells is the largest organelle. It has its functions cut out in the form of being the command-and-control center of cellular activities and also being the storage destination of the DNA of a cell. As far as its structure is concerned, the nucleus is seen as dark and round and is enclosed by the nuclear membrane. The nucleus is a porous membrane-like cell membrane and acts as the wall between the cytoplasm and the nucleus. The tiny spherical bodies inside the nucleus are called nucleolus.
The nucleus also transfers chromosomes that are thread-like thin structures, which in turn ship another prominent structure called a gene. These genes are hereditary units in organisms and are crucial in determining the inheritance of traits from one generation to another. Therefore, the nucleus is the most vital point for the determination of characters and functions of cells, for monitoring cellular activities.
Endoplasmic Reticulum
Unlike other components, the Endoplasmic Reticulum is made up of a network of membranous tubules, which play a major role in forming the skeletal framework and perform various important functions, such as protein production, detoxification, and lipid production. Moreover, this membrane is very small in size and is generally located inside the Cytoplasm.
There are two kinds of Endoplasmic Reticulum:
- Rough Endoplasmic Reticulum: These are made of cisternae, tubules, and vesicles, and are found across the cell, engaged in protein formation.
- The smooth Endoplasmic Reticulum: It is the storage organelle and deals with the production of lipids, and steroids, and plays a vital role in cell detoxification.
Mitochondria
The most important component of the cell organelle, as it plays a major role in cellular respiration as well as the storage of energy inside the cell, by converting them to ATP molecules. Because of this reason, this membrane-bound organelle is referred to as the powerhouse of the cell.
Mitochondria are generally referred to as the powerhouses of the cell since they produce energy-rich molecules. The mitochondrial genome, maternally inherited in several organisms, is usually double membrane-bound and is sausage-shaped, found in all eukaryotic cells.
Mitochondria are centres of aerobic respiration in the cell and they generate energy in the form of ATP form helping in molecular transformation. These mitochondria can boast of their own circular DNA, RNA molecules, ribosomes (the 70s), and certain distinct molecules needed in protein formation and synthesis.
Plastids
Plastids have various important purposes, such as storing starch, fats, and proteins, as well as playing an important role in essential processes such as Pollination and Photosynthesis. These Doubled membranes are of three types, Chloroplast, Leucoplast, and Chromoplast.
Chloroplasts are double membrane-bound organelles in different shapes, be it spherical or oval or more. They are seen in mesophyll cells of leaves that store chloroplasts and other carotenoid pigments that play a major role in tapping light energy for photosynthesis. Stroma is the space surrounded by the inner membrane
Chromoplasts
These also comprise fat-soluble, carotenoid pigments such as xanthophylls, carotene, etc, that give plants customary and characteristic colors.
Leucoplasts are the colorless plastids that store nutrients. Amyloplasts are known to store carbohydrates, whereas aleuroplasts store proteins and elaioplasts preserve oils and fats.
Microbodies
These organelles are useful for biochemical breakdown, or oxidation inside the cell, which involves the conversion of fatty acids into carbohydrates. These types of cells are commonly found in plant and animal cells, and glycosomes and peroxisomes are common examples of Microbodies.
Ribosomes
For the synthesis of proteins, the non-membrane organelles are required, which are known as Ribosomes. Besides, this membrane is commonly found in the endoplasmic reticulum and the cell’s cytoplasm. Furthermore, the main components of Ribosomes, such as Ribosomal Proteins and Ribosomal RNA. These are found as tiny particles in many cells and are mainly composed of 2/3rd of RNA and 1/3rd of protein. Ribosomes are generally encompassed inside the endoplasmic reticulum or can be seen freely spread in the cell’s cytoplasm. The major and basic function of the ribosomes is protein synthesis.
Other major constituents among the list of organelles
Golgi Apparatus or Golgi Complex is a membrane-bound organelle and consists of flattened, stacked pouches called cisternae, formed in a series. This cell organelle transports, alters, and packs proteins and lipids to different destinations. Golgi Apparatus can be seen inside the cytoplasm of a cell.
Cytoskeleton is an unbroken network of filamentous proteinaceous structures running throughout the cytoplasm, between the nucleus and the plasma membrane. Its functions include providing the shape and protecting cells against deformation.
Cilia and Flagella: Small projections that determine cellular movements, Centrosomes and Centrioles, Vacuoles, or storage bubbles complete the list of cell organelles.
Conclusion
The article above provides a comprehensive description of cell organelles and their functions. In addition to this, we also talked about the different types of cell organelles in detail. And if you find any difficult topics or chapters like this, in the subject often, then it would be a good idea to join the online coaching program. One such unique online interactive class is offered by the Tutoroot platform and comes with various benefits such as expert staff guidance, doubt-clearing sessions, and a lot more.
Frequently Asked Questions
Why is it called organelles?
An organelle is a unit, located inside the cell and performs a specific function. Therefore, the word organelle is derived in such a way that Elle becomes a suffix to the word organ
What are two types of organelles?
Membrane-bound and non-membrane-bound
Which part of the cell contains organelles?
The cytoplasm of the cell contains cell organelles
Which organelle plays a role in intracellular digestion?
The lysosome is the organelle that plays a major role in intracellular digestion.
Which organelle is like the brain of the cell?
The nucleus is the brain of the cell.