Introduction to Centromere
A Centromere is essentially a restricted region within the chromosome that participates in the crucial function of cell division in the eukaryotic cells. The DNA structure can have several types and there are different tasks or roles to perform. Here it is worth noting, that this is one of the core and fundamental concepts in the Biology syllabus that is not only important for current learning but also useful for higher studies.
What is a Centromere?
The Centromere is the specific portion within the DNA sequence in the chromosomes that connects the sister chromatids during the period of cell prophase. The chromosomes are basically segregated in the long arm q and the short arm p.
The Functions of Centromere
This is the region which connects the two sister chromatids and is known as the point of attaching the spindle fibres.
During the process of cell division in the eukaryotic cells, the role of the Centromere for cell division is aligning and segregating the chromosomes.
Centromere is responsible for the separation of sister chromatid and adhesion, chromosome movement, mitotic and heterochromatin checkpoint control, microtubule attachment, and other processes.
The Centromeres act as the signal processing centres which regulate the progression of the cell cycle.
The Centromere acts as the vital part in the cell's formation as it is responsible for binding the newly formed chromosomes that are known as the sister chromatids.
Types of Centromere
These can be divided into two sub-categories, namely
Point Centromeres
In this type, mitotic spindle fibres are connected to particular DNA sequences.
Here, the proteins connect with individual DNAs and make the mitotic spindle fibre bond possible.
In this case, the connection between protein and the DNA is present irrespective of its location and other factors.
Regional Centromeres
Regional centromeres are used mostly in humans and eukaryotic cells.
Here, the DNA sequence does not determine the location of centromeres. Rather, other factors combine to contribute in calculating this site.
To define centromeres of this kind, the epigenetic marks inform the proteins about their location. This is required to make a connection with the mitotic spindle complex.
Interesting Fact
These epigenetic marks are nothing but chemical changes made to the DNA with the use of enzymes. These are easily added or removed to/from the DNA without altering any information present in DNA.
Multiple - Choice Questions
Choose the most appropriate option with respect to the Centromere.
Facilitates even distribution.
Restricted chromosomal region.
Connecting sister chromatids.
Connecting to spindle fibres.
Ans: a
Centromeric proteins are the ones which connect to the Spindle Fibres.
True
False
Ans: b
Initially, centromeric DNAs were identified in
Humans.
Bacteria.
Fungi.
Yeast.
Ans: d
Choose the primary reason which states why Chromosomes are condensed.
For facilitating accommodation.
For facilitating cell division.
To provide cell division in daughter cells.
Always condensed.
Ans: c
Choose the appropriate part option which is critically responsible for even distribution of parental DNA.
Spindle fibre.
Centrioles.
Telomere.
Centromere.
Ans: b
Choose the accurate number of satellite sequence elements in yeast centromere.
3
5
2
4
Ans: a
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FAQs on Centromere
1. Where are the Centromeres located?
According to the definition of the Centromere, the Centromeres are typically considered to be located in the central part of the chromosome. However this is not necessarily always the case since they can also be present around mid-region or at a different place. The proteins that are placed at specific sites are called the kinetochores. Thus this explains the probable position or location where the Centromeres are usually located in the body.
2. What are the primary objectives of the Centromeres?
Centromeres is the specific part of the DNA that helps in replicating the chromosome for transmitting into the sister chromatids during the process of mitosis or meiosis. The Centromere is used for aligning and segregating the chromosomes at the time of the cell division. The Centromeres are also used for regulating the progression of the cell cycle. Beyond this the Centromeres are also used in a wide range of processes within the body.
3. Which are the main categories of Centromeres that are present within the body?
Fundamentally, there are two types of Centromeres that are present in the body and they are: point Centromeres and the regional Centromeres. The point Centromeres are essentially proteins that are used for connecting with the specific DNA sequences, while the regional ones rely on various factors for finding the location of the binding. The regional Centromeres are used in humans as well as eukaryotic cells.
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6. What is the Function of Centromere?
It is a specific region of DNA which helps the replicated chromosome to transmit into the two sister chromatids during meiosis or mitosis process.
7. How many Types of Centromeres are Present?
There are typically two kinds of centromeres – point centromeres and regional centromeres. Point centromeres are the proteins that connect with specific DNA sequences, whereas regional ones rely on several factors to find the location of binding.
