The term Organelle is derived from the word “organ” and refers to the parts inside a cell that perform a specific function. These parts are usually isolated from the rest of the cytoplasm by intracellular membranes. These membranes can be like plasma membranes or are made up of different groups of fats and proteins. The properties of the membrane are due to its origin, as is the case with mitochondria or plastids, or because of its specific function, as it appears in the nuclear membrane. Some organelles are not bound to the membrane and are present in large RNA and protein complexes, such as ribosomes.
Cells face three major challenges when it comes to creating organelles. The first is the formation and maturation of organelle building blocks. It contains the membrane, the molecules attached to its large membrane, and the cytoskeleton mechanism that forms the organelle. In addition, organelles need to contain the right chemicals – proteins, amino acids, fats, and carbohydrates or their monomers, cofactors, enzymes, and signaling molecules. These molecules must be specific and often actively transmitted to the subdivisions of these cells. Finally, the organelles should be preserved throughout the life of the cell and should be specially separated during cell division. There are many different strategies that cells around the world use to accomplish these tasks.
Often different types of cells dominate a particular organelle depending on its primary role in the body. For example, parenchyma cells in the leaves are filled with chloroplasts, while this organelle often lacks root-forming cells. One can be a rapidly changing vacuole in cell-borne active organisms such as paramecium. Cells involved in protein secretion usually have a well-developed Golgi network and a prominent coarse endoplasmic reticulum.
Examples of Organeles
In eukaryotes, almost every cell has a nucleus (exceptions, animals include red blood cells). Other commonly seen organs are mitochondria, plastids (inter-atrotrophic), endoplasmic reticulum, golgi apparatus, lysosomes, and vacuoles. Certain cells, such as neurons, also have synaptic vesicles. All of these structures are bound to the membrane. Molecular complexes such as ribosomes, splicesomes, centrioles, and centrosomes are not attached to the membrane, but most cells have vital organs, which perform important functions such as cytoskeleton regulation, protein synthesis, and RNA processing.
Bacteria contain organelles that bind to proteins and fats. It can be made of simple monolayer (eg: carboxysomes) or bilayer (magnetic). The organs in the prokaryotes are being studied more extensively, especially as better experimental tools emerge.
Types of Organelles
Organelles can be classified in several ways. The simplest classification is based on their originality: whether they are found in prakaryots or ukraites. Although many important biochemical pathways are involved in a common lineage between these two cell lineages, a complex cell scheme separates most eukaryotic cells. The origin of this particular type of complication is not known. Eukaryotes are able to perform chains with excellent structured biochemical reactions mainly due to their subcultural skills. Furthermore, the presence of organelles, which ATP can produce, also provides the energy needed to drive these metabolic reactions and maintain large cells. On the other hand, prokaryotic genetic material is found in semi-structured areas called nucleoids, commonly called a part of the cytoplasm that contains most of the genetic material of the cell. The magnet is another type of prokaryotic organelle, and it is practically unique in binding to the lipid bilayer. These structures are formed by the structure of actin-like cytoskeleton, which is involved in the formation and position of organelles within cells.
This simple classification sometimes encounters difficulties, especially with structures such as mitochondria or chloroplasts that are archaeological terms. However, as a general rule, prokaryotic organelles are often simpler with less complexity in terms of chemical composition and membrane structure.
Even in eukaryotic cells, the presence and nature of the membrane around the cellular compartment is a common method of classification. While large parts such as lysosomes and endoplasmic reticulum are bound to the lipid biliary, many important organelles, but small parts, interact freely with the cytoplasmic environment. These organelles are not filled with fluid and instead are solid blocks of protein, RNA, or both. Ribosomes and splenosis are common examples of non-membrane-bound organelles. Some people also classify the cell walls of plants and bacteria under this category, as they consist primarily of cellulose. However, it is located outside the cell membrane and thus cannot be considered an intracellular structure.
Finally, some organelles can reproduce freely from the cell cycle, because they have their own genetic material. Plastids and mitochondria are of particular importance here. However, when they reproduce despite cell softening in the G0 phase, they need to import most of the replication mechanism from the cytoplasm, which is closely related to the cell’s needs. Mitochondria and chloroplasts have a unique genetic material, which is independent of the rest of the nucleus, and in many cases, their number can change within the cell. For example, muscle fibres that experience an increase in their ATP requirement often respond by increasing the number of mitochondria in the cell. Plants and other autotrophs can show similar adaptations to chloroplasts.