Chromosomes are thread-like or rod-shaped structures present in cellular organisms that consist of DNA information. In the eukaryotic organisms, they are present in the nucleus of the cells, whereas, in the prokaryotic organisms, there is just one ring-shaped chromosome, commonly known as the genopore. Chromosomes have genes that contain the hereditary information of that organism.
One chromosome contains two similar structures that are held together at a point called the centromere. Each of these is referred to as a chromatid. Hence, one chromosome has two chromatids that are connected by a centromere. Chromosomes, therefore, possess an X shape. The study of cell division and chromosomes is referred to as cytogenetics.
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The above structure is a simple diagram of the chromosome. However, the prokaryotic and eukaryotic cells have a different chromosome structure. But they are similar in many ways. The similarities between the prokaryotic and eukaryotic chromosomes are given below.
Both the prokaryotic as well as eukaryotic chromosomes have DNA, which is the genetic information.
The negatively charged DNA which is present in both the types tends to react with the positively charged proteins for neutralizing their charges.
The genetic material in both the chromosomes contains the coding as well as the non-coding sequences.
DNA methylation in both chromosomes is responsible for DNA activation.
Both of these groups have extra-chromosomal genetic materials. The DNA of mitochondria and the chloroplasts in the case of eukaryotes, and plasmids in the prokaryotes.
The genetic material in eukaryotes is properly organized in the form of distinct structural bodies, which are known as chromosomes. In the prokaryotic cell, the chromosome formation is not present.
The eukaryotic cells always have two or more than two chromosomes in a single cell, whereas the prokaryotic cell has just one chromosome in a single cell.
Every eukaryotic chromosome contains a linear DNA having two ends, whereas a prokaryotic chromosome possesses a circular DNA that is covalently closed.
The eukaryotic chromosomes are separated from the cytoplasm by the nuclear membrane, whereas the prokaryotic chromosomes do not have a nucleus and are directly in contact with the cytoplasm.
Basically, the prokaryotic chromosome is a primitive type of chromosome, whereas the eukaryotic chromosome is an advanced type.
Chromosomes can be defined as the thread-like or rod-like structures which are found in the cellular living organisms which contain the genetic material deoxyribonucleic acid or DNA. The DNA plays an important part in heredity as the characteristics of each reproducing parent is passed down to the offspring. In eukaryotes, the chromosomes are present in the nucleus whereas in the prokaryotes there is only a ring-shaped chromosome called the genophore. The chromosomes carry the genes which have hereditary information and give the organism its characteristics. A single chromosome has two homogeneous or similar structures that are held together at a certain point called the centromere. The structures are called the chromatids which means one chromosome has 2 chromatids that are connected by the centromere. The chromosome appears like the alphabet X. Cytogenetics is the study of chromosomes as well as cell division.
The chromosomes and chromatids differ from each other and their differences are given as below:
Chromosomes have the genetic material DNA whereas chromatids help the cells in cell division and their duplication.
The chromosomes are present throughout the whole cell life cycle but chromatids are formed when the cell has to undergo cell divisions.
Chromosomes are not the copies of each other but the sister chromatids present in the chromosomes are copies of each other and are identical.
Chromosomes have centromeres to which the chromatids are attached and the sister chromatids have centromeres only.
In chromosomes, DNA is used for the synthesis of macromolecules like proteins but it is not used by chromatids.
Vedantu experts have covered all the major aspects of the difference between Chromosome and Chromatid.
1. What is the Difference Between Sister Chromatids and Chromosomes?
The difference between chromosome chromatids is as follows -
A chromosome is referred to as a thread-like structure which is present in the nucleus or in the nuclear region of the cell’s cytoplasm. It consists of one molecule of DNA and proteins that carry the necessary genetic information of that organism.
On the other hand, as the cell prepares for the division, each of the chromosomes gets copied. Two copies of the same chromosome are referred to as the sister chromatids. They are identical to each other and are attached to one another by the proteins known as cohesins. The point at which the sister chromatids are attached is known as the centromere, where the bond is the tightest.
2. What are the Similarities Between Chromosomes and Chromatids?
Chromosomes and chromatids are similar to one another in so many different ways. The similarities between the chromosomes and chromatids are given as follows.
Both the chromosomes and the chromatids get formed through the molecules of DNA.
Both of them are found inside the nucleus of the eukaryotic cells.
Genes and genetic information is embedded within both the chromosomes and chromatids and both of them play an essential in possessing the hereditary information.
Both the chromosomes and the chromatids tend to contain the histone proteins that are associated with them.
Both of them are involved in the mitosis cell division.
Both of them contain chromatin, which plays a vital role in allowing the DNA to remain coiled in both their structures.
3. What are the similarities between the chromosomes of prokaryotes and eukaryotes?
There are quite a lot of similarities between the prokaryotic and eukaryotic chromosomes which are discussed below:
DNA is the genetic material which is present in both prokaryotic and eukaryotic chromosomes.
Both have negatively charged DNA associated with positively charged proteins which neutralizes each other.
Both the DNA has non-coding and coding sequences.
DNA methylation occurs in both chromosomes of prokaryotes and eukaryotes.
The chromosomes of both prokaryotes and eukaryotes have extra-chromosomal genetic components or materials. These are mitochondria and chloroplasts that occur in eukaryotic chromosomes and in prokaryotes in plasmids.
4. What are the differences in the chromosomes of prokaryotes and eukaryotes?
The differences in the prokaryotic and eukaryotic chromosomes are as follows:
The DNA in eukaryotes is organized in a proper manner which are in the form of distinct structures called chromosomes. In the prokaryotes, the chromosome is not present.
Eukaryotes have two or more than two chromosomes in the single cell. On the other hand, prokaryotes have one chromosome in a single cell.
In eukaryotes, the chromosome is a linear DNA which has two ends but the prokaryotic chromosome has a circular DNA which is closed.
In eukaryotes, the chromosomes are separated from the cytoplasm by the nuclear membrane. On the other hand, prokaryotic chromosomes are directly connected to the cytoplasm as they do not have a nucleus.
5. Why are chromosomes important for living beings?
Chromosomes are crucial for the proper functioning and growth of the organism as well as cell division which is important for the survival of the organism. In the process of cell division, the DNA has to remain intact and be distributed evenly among the cells so that the daughter cells get the proper amount of DNA required. Chromosomes make sure that the genetic material is copied accurately and evenly distributed during cell divisions. However, anomalies still occur in such processes. This leads to diseases or disorders. This can happen due to changes in structure of chromosomes as well as numbers. For example, in the case of leukemia and some cancers which are caused due to chromosomal anomalies. Additionally, it is important for reproduction as well. The male and female gametes should have the correct amount of chromosomes as well as the correct structure for a successful reproduction. You can learn more about Chromosomes here at Vedantu Website and download the PDF file.
6. Define chromatids and its functions in the cell.
Chromatids are the structure where the cells can store two copies of their information which is required in cell division. It is imperative that the daughter cells are healthy and functional which has the complement copy of the parents’ DNA. Having two copies of the DNA joined together ensures the cell that gives one copy of each daughter cell. If sister chromatids fail to separate during the process of cell division then this can lead to mutations.
7. What are chromosomal disorders?
Chromosomal disorders or diseases can occur in the chromosome when there are mutations or abnormalities in the chromosome and are a type of genetic disorders. This can occur due to change in one or more chromosomes or changes in the regular arrangement of the chromosomes. They are broadly divided as aneuploidy in which there is a loss or gain of chromosome during the process of cell division and polyploidy in which the entire set of chromosomes increases due to failure of cytoplasm division or cytokinesis during cell division.
Examples are: Klinefelter syndrome, Turner syndrome and Down’s syndrome.