Difference Between Centrosome and Centromere

The key difference between centrosome and centromere is that centrosome is a cell organelle that consists of two centrioles while centromere is a point that joins two sister chromatids of a chromosome together.

Cell division is an important process occurring in multicellular organisms. There are two types of cell division processes as mitosis and meiosis. Mitosis produces genetically identical daughter cells while meiosis produces gametes that are necessary to carry out sexual reproduction. Moreover, in both cell division processes, the nuclear division is common. Here, chromosomes duplicate and separate accurately into daughter cells. For this purpose, centrosomes and centromeres are essential structures of a cell. Each cell has two centrosomes at two poles. They are cell organelles made up of centrioles. On the other hand, centromeres are constricted regions that joint sister chromatids together in a chromosome.

CONTENTS

1. Overview and Key Difference
2. What is a Centrosome
3. What is a Centromere
4. Similarities Between Centrosome and Centromere
5. Side by Side Comparison – Centrosome vs Centromere in Tabular Form
6. Summary

What is a Centrosome?

A centrosome is a cell organelle essential for cell division. It is the major microtubule organizing centre of the cell. Structurally, a centrosome is 1 µm in size and it is not a membrane-bound organelle. A dividing cell has two centrosomes at two poles. A single centrosome consists of one or two centrioles. Hence, each mitotic cell generally has two centrosomes and four centrioles. A centriole is a small cylindrical organelle present in most eukaryotic cells.

Moreover, centrioles contain tubulin protein as their main protein. The cylindrical structure of centriole comprises several groups of microtubules that are in 9 + 3 structure. When two centrioles are arranged perpendicular to each other, it forms a centrosome. The centrosome works as the main center of microtubule arrangement and it regulates the progression of the cell cycle. During cell division, centrioles play a significant role by determining the plane in which the nuclear division takes place within the cell. Furthermore, centrosomes form spindle fibers to attach with the centromeres of the chromosomes.

Dysfunctional centrosomes can cause cancer, Alstrom syndrome and various neurological disorders. Moreover, centrosome abnormalities and dysfunctions are associated with several types of infertility.

What is a Centromere?

A centromere is a structure present within a chromosome that connects two chromatids together. It is a visible point of constriction in the chromosome. Moreover, centromere contains repeated sequences of DNA and specific proteins. These proteins create a disk-shaped structure called kinetochore at the centromere. Kinetochores are involved in cell signaling for the progression of cell cycle and it serves as the main attachment site for spindle microtubules.

Centromeres are of two types: regional centromeres and point centromeres. Point centromeres establish a direct single line of attachment per chromosome and bind to different specific proteins. These proteins recognize highly efficient DNA sequences. But regional chromosomes establish multiple attachments per chromosome. Regional centromeres are more prevalent in cells of organisms rather than point centromeres.

What are the Similarities Between Centrosome and Centromere?

• Both centrosome and centromere are important structures of a dividing cell.
• Furthermore, they are involved in the accurate separation of chromosomes among the daughter cells.

What is the Difference Between Centrosome and Centromere?

The key difference between centrosome and centromere lies in their structures. That is; the centrosome is a cell organelle composed of two centrioles arranged perpendicularly while centromere is a region of a chromosome composed of specialized DNA sequences. A further difference between centrosome and centromere is that the centrosomes form spindle fibers while centromeres join sister chromatids together in a chromosome.

Furthermore, centrosomes are located at the two poles of a dividing cell while the centromeres are located on the chromosomes. Thus, this is also a difference between centrosome and centromere.

Summary – Centrosome vs Centromere

A centrosome is an organelle which is 1 µm in size. It consists of two centrioles arranged perpendicularly. In addition, one cell has two centrosomes. Centrosomes form spindle fibers during the cell division; these are essential to pull sister chromatids towards the poles. On the other hand, centromere is a region of a chromosome. It is the region that connects two sister chromatids together. Moreover, spindle fibers attach with chromosomes from centromere regions during the cell division. It is made up of specialized DNA sequence. Thus, this is a summary of the difference between centrosome and centromere.

Reference:

1. Schatten, Heide. “The Mammalian Centrosome and Its Functional Significance.” Histochemistry and Cell Biology, Springer-Verlag, June 2008, Available here.
2. “Centromere.” Wikipedia, Wikimedia Foundation, 1 Apr. 2019, Available here.

Image Courtesy:

1. “Centrosome (borderless version)-en” By Kelvinsong – Own work (CC BY 3.0) via Commons Wikimedia
2. “Figure 10 02 03” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia