Every living thing is composed of cells which are the fundamental units of life. These are responsible for everything that happens within the organism. Animals, plants, and fungi all are composed of one type of cell or more than one type of cell. Within the cell, there are several organelles participating in different cellular activities. A cell is nothing without its organelles. Each organelle is specialized for its task, whether gene regulation, protein synthesis, or any other function occurring within the cell.
Plant cells are highly complex structures with several unique organelles. Most characteristics of plant and animal cells are the same. However, some organelles are present in animal cells but absent in plant cells. Now, if you are wondering whether centrosomes are present in plant cells, then let’s find out what they are, their functions, and much more about them in this article.
What is a Centrosome?
It is an organelle located in the cell’s cytoplasm and is involved in cell division. Centrosome duplicates before the division begins, and during the division process, it migrates to the opposite poles. Centrosomes are responsible for the formation of spindle fibers during the process of mitosis. Other than that, they regulate the progression of the cell cycle and the assembly of microtubules. It is considered the main microtubule organizing center (MTOC) of cells.
Centrioles are the central part of a centrosome and function as basal bodies involved in several other functions performed by the centrosome. They are responsible for the development and formation of flagella and cilia. A defined number of centrioles and centrosomes are present inside each cell to regulate the normal functioning of an organism.
Do Plant Cells Have Centrosomes?
Plant cells do not have centrosomes. These organelles are used in the process of division and for coordinating microtubules. Instead of centrosomes, plant cells use other MTOC structures for coordinating microtubules during mitosis. Although plant and animal cells are similar in many ways, they have the same cytoskeleton assembly, but plant cells lack centrosomes that are present in animal cells. Plant cells are still capable of forming spindles, assembling microtubules, and nucleation of those microtubules. MTOC structures play the role of centrosomes in plant cells.
Where are Centrosomes Located?
Centrosomes are specialized organelles responsible for organizing microtubules during division. Centrosomes are present within the cytoplasm of animal cells near the nucleus. They are in close association with the nuclear envelope. During each mitotic cycle, the centrosome duplicates and migrates to opposite poles. The division or duplication of centrosomes occurs during the S phase of the cell cycle.
Structure of Centrosomes
Centrosomes consist of centrioles. There are two centrioles present within the centrosome. These centrioles are arranged orthogonally and are surrounded by an electron-dense matrix called the pericentriolar material (PCM). Both centrioles are structurally different from one another, and each centriole consists of nine triplets of microtubules. Centrioles are barrel-shaped and lie perpendicular to each other. The two centrioles are the mother centriole and the daughter centriole. Mother centrioles have nine appendages divided into two sets and are located at the two distal parts of the centriole. The daughter centriole lacks these appendages and is 80% of the length of the mother centriole. Mother centriole plays a role in the anchoring of the microtubules.
What are the Functions of Centrosomes?
Centrosomes perform several functions few of their functions are mentioned here in detail:
- It allows the cell membrane to change its shape, allowing it to pinch into two during cell division.
- It ensures that all chromosomes are equally distributed between the two cells. It creates and shortens the mitotic spindle fibers accordingly.
- Centrosome is also responsible for the changes in the shape of the cytoplasm during other processes, such as those that occur in phagocytosis.
- The main function of centrosomes is their role as a microtubule organizing center (MTOC). It is responsible for organizing the microtubules during their assembly and nucleation.
- Centrosomes generate the microtubules and cilia and flagella originate from these microtubules. Cilia and flagella are used by organisms to help them move.
- Centrosomes also play a role in the regulation of the cell cycle. Besides mitosis, they are essential for cytokinesis too.
Importance of Centrosomes
Centrosomes are very important organelles found inside the cells as they are the MTOC. It maintains the polarity of the cell and influences the positioning of different organelles within the cell. Centrosomes are involved in the organization and nucleation of microtubules, and the most unique thing about them is they can be resynthesized even after destruction. Centrosomes play an important role in different processes occurring inside the cells, including chemotaxis, maintenance of cell polarity, cell migration, assembly of spindle fibers during division, distribution, and positioning of organelles, and directional vesicle transport.
Conclusion
Plant cells and animal cells have several distinct features. The presence or absence of some organelles makes them differ from each other. One such organelles is the centrosome. Plant cells do not have centrosomes, whereas animal cells do have them. The centrosome consists of two centrioles and is considered the microtubule organizing center (MTOC). It is located within the cytoplasm lying close to the nucleus. It is involved in the organization, nucleation, assembly, and coordination of the microtubules and spindle fibers. During the mitotic division, it divides into and migrates to the opposite side of the cell. Plant cells have MTOC structures as an alternative to the centrosome. These structures perform the same function as the centrosome.
Frequently Asked Questions (FAQs)
Here are a few frequently asked questions about centrosomes:
Are centriole and centrosome the same?
Centrioles are a part of the centrosome. They are barrel-shaped organelles found within the centrosome.
How do plant cells divide without a centrosome?
Most land plants have an ancestral mitotic spindle in the absence of centrosomes. This mitotic spindle with a cytokinetic apparatus composed of a predictive preprophase band (PPB), is used for the division of plant cells.
What do plant cells use instead of centrioles?
Instead of centrioles, plant cells make special vesicles from Golgi bodies that they use during their division process.
What do plant cells not have in mitosis?
Plant cells lack centrioles during the process of mitosis.
Jeannie has achieved her Master’s degree in science and technology and is further pursuing a Ph.D. She desires to provide you the validated knowledge about science, technology, and the environment through writing articles.