Both these terms chromosomes and chromatid are used in the study of DNA (Deoxyribonucleic acid). It should be kept mentioned that DNA is found in almost all the organisms including humans and; it is the hereditary material which is transmitted from the parents to the offspring. As their spellings are quite the same and both these terms are interrelated, people find it difficult to distinguish between both of them. They can be differentiated as chromosomes are the thread-like structures that form the DNA molecule, whereas either of the two strands formed when a chromosome duplicates itself as part of the early stages of cell division is known as chromatid.
What is Chromosome?
A thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes is known as the chromosome. In a human body, each of the cells contains 46 individual chromosomes or 23 pairs of chromosomes. Out of these 23 pairs of chromosomes, 22 pairs are same in the males and females, whereas the twenty-third pair is different in males and females. The 22 similar chromosome pairs are called the autosomes, whereas the one distinguishing in male and female is called the sex chromosome. The pairing of chromosomes takes place in mitosis, which is an essential process of the cell division. It should be kept noted that chromosome is made up of DNA and protein; it carries the reproductive information which is passed on from parents to the offspring. The shape of the chromosome is different in eukaryotes and prokaryotes; in eukaryotes, they are organized in the linear pattern, whereas in prokaryotes they are set in the circular pattern. The point dividing the chromosomes into two sections or arms is known as the centromere. At the same time, centromere determines the location of the specific genes and is also responsible for giving chromosome its characteristic shape.
What is Chromatid?
The chromatids are joined by a single centromere and later separate to become individual chromosomes. When we talk about the pair of chromosomes, we refer to the presence of the two chromatids. In the chromosome pair, chromatids are tied up or united by using the centromere. When the two chromosomes are separated as individual after removal of the centromere, they are called the sister chromatids as they resemble each other. The chromatids are equally essential as the chromosomes in the process of mitosis.
Chromosome vs. Chromatid
- Chromosomes are the threadlike structures that form the DNA molecule, whereas either of the two strands formed when a chromosome duplicates itself as part of the early stages of cell division is known as chromatid.
- When we talk about the pair of chromosomes, we refer to the presence of the two chromatids. In the chromosome pair, chromatids are tied up or united by using the centromere.
- In other words, we can say that chromatid is the sister of the chromosome.