Centrosome vs. Centromere

Main Difference

The main difference between Centrosome and Centromere is that Centrosome is an organelle in a eukaryotic animal cell which acts as a center for microtubules organization, whereas Centromere is a constricted region of the two chromosomes in eukaryotes where a pair of similar chromatids join together to form this region.

Difference Between Centrosome and Centromere

Comparison Chart

Centrosome vs. Centromere

Centrosomes are the organelles in living eukaryotic animal cells from where the microtubules arise and act in their part in the division of a cell, whereas centromere is formed by the constriction of two sister chromatids of a chromosome attach and form a constricted region. Centrosomes are made up of microtubules, centrin, cenexin, and tektin, whereas centromeres are made up of centric heterochromatin. Centrosomes are composed of two centrioles that arrange themselves in an orthogonal manner, whereas centromere is formed by centric heterochromatin which is surrounded by pericentric heterochromatin.

Centrosomes nucleate microtubules inside a cell to form a spindle apparatus during the prophase stage of cell division, whereas, a centromere holds sister chromatids during the cell division as being the constricted region and a holding point. One of the main difference between these two is that centrosome is a cylindrical structure which forms the spindle apparatus by controlling cell’s microtubules, on the flip side, the centromere is just a region of DNA that holds two sister chromatids during the cell division.

Centrosomes duplicate only once during the S phase, and then each daughter cell receives one centrosome per one cell cycle; however, the centromere is found in each linear monocentric chromosome. Centrosomes are usually present in animal eukaryotic cells, whereas centromere is present in all eukaryotes.

What is Centrosome?

Centrosomes are the organelles in living eukaryotic animal cells from where the microtubules arise and act in their part in the division of a cell as described in detail above. These centrosomes are made up of microtubules, centrin, cenexin, and tektin mainly. Centrosomes are composed of two centrioles that arrange themselves in an orthogonal manner and nucleate microtubules inside a cell to form a spindle apparatus during the prophase stage of cell division and this process further proceeds till the end of the cell cycle. These two centrioles are surrounded by peri-centriolar material, and their microtubules consist of y-tubulin, ninein, and pericentrin. Nine triplets microtubule assemble in a structure to form a centriole of the centrosome.

Centrosomes are the main cell organelles found in the animal eukaryotic cells that serve as the main center during cell division and progression of the cell cycle by acting as a regulator and aligning the organization of the microtubules. It is evolved into animal eukaryotic cells only as the plant cells do not contain these organelles. These organelles are absent in plants and fungi, and these cells have other centers for the organization of microtubules. Centrosomes are situated in the amorphous mass of peri-centriolar material. These materials are composed of proteins and are mainly responsible for polymerization of microtubules and their termination.

In the interphase of the cell cycle, these centrosomes get connected to the nuclear membrane in the cell. During mitosis, this attached membrane breaks apart and then these centrosome’s microtubule interacts with the chromosome and builds mitotic spindle, which further leads to progression in the cell cycle. Daughter cells receive one centrosome that contains two centrioles. During the prophase in cell division, these two centrosomes migrate to their respective poles and lead to the formation of the mitotic spindle. Centrosomes are key components for the survival of an organism. However, without centrioles, mitosis cannot proceed normally.

Centrosome acting as the main center of the main center for microtubule organization regulates the progression of the cell cycle. Centrosomes duplicate only once during the S-phase. As spindle microtubules that are attached to centromeres of each chromosome for their segregation. These spindle microtubules when the contract, the chromosome segregate towards the opposite poles of the cell, thus leading to the creation of two daughter cells. Per cell cycle, each daughter cell gets one centrosome per cell cycle. Centrosomes are usually present in animal eukaryotic cells. These centrosomes are evolved in animal eukaryotic cells only; that’s why plants and fungal cells lack chromosomes. Contrary to animal cells in plant cells, spindles are formed independently without control of centrosomes.

What is Centromere?

The centromere is a constricted region on chromosomes formed by the constriction of chromosomes in that area, and this is the point where the two sister chromatids of a chromosome are connected. These chromosome contains important information regarding that organism and is present in all eukaryotes. The central part, the centromere is the part of the chromosome that determines the formation of kinetochore which are complex structures where the spindle fibers get attached and then pull the sister chromatids apart during mitosis. The kinetochore is divided into two components, the inner kinetochore which is associated with the entire life of a cell and the other one is the outer kinetochore whose purpose is to interact with the spindle, and it is formed only during the division of the cell.

Centromeres can be divided into regional and point centromeres. Regional centromeres are usually formed on preferred DNA sections but can also be formed on others too. Point centromeres are compact and are highly efficient in recognizing the DNA sequences. The Centromeres divide sister chromatids into two arms based on the length of these two arms, these arms are known as p-arm and q-arm. Based on the length of these two arms of chromatids, there are four types of chromosomes. Ones with very short p-arms are known as telocentric chromosomes, where the centromere is situated at the end of these sister chromatids. Acrocentric have p arms significantly shorter than q-arms, submetacentric have similar p and q arms and metacentric are the chromosomes with identical in length of sister chromatids.

Centromeres are made up of centric heterochromatin (Double-stranded DNA) and are surrounded by pericentric heterochromatin. Centromere holds sister chromatids during the cell division as being the constricted region and a holding point. A centromere is merely just a region of DNA that holds two sister chromatids during the cell division. The centromere is found in each linear monocentric chromosome of eukaryotes. This centromere plays the role of providing the site in the middle of chromosomes for the binding of microtubules with the kinetochores.

It depends upon the number of centromeres present on chromosomes organisms can be differentiated. There are monocentric organisms that have a single centromere per one chromosome and the second ones are holocentric organisms that consist of more than one centromere per one chromosome. As discussed earlier, Centromeres are present in all eukaryotes.

Conclusion

Centrosomes are cylindrically structured organelles in living eukaryotic animal cells from where the microtubules arise and, play their part in the division of a cell, whereas centromere is the center of attachment for chromosomes that is formed by the constriction of two sister chromatids of a chromosome.