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Chromosome vs Chromatid

A chromosome is the most condensed form of DNA that is found during the M-phase of cell division. On the other hand, chromatin is the identical half of a duplicated chromosome, found at the interphase. 

The genetic count of an organism is determined in terms of chromosome pairs; for example, humans have 46 chromosomes (arranged in 23 pairs). 

How are Chromosome and Chromatid Related to Each Other

As we know, a chromosome is composed of a single DNA molecule that gets doubled during the interphase of cell division. Thus, each chromosome contains two copies of DNA strands during interphase, where each DNA strand is referred to as chromatid. In higher organisms, the double-stranded DNA wraps around a special class of proteins called histones. The association of a double-stranded DNA with its histone proteins is known as chromatin. Thus we can conclude that chromosome and chromatid are related to each other and are composed of the same basic structure. 

What is the Difference between a Chromosome and a Chromatid

Chromosome vs Chromatid

Chromosome vs Chromatid

BasisChromosomeChromatid
Consists ofA single, double-stranded DNA moleculeTwo DNA strands joined together by a centromere
StructureA thin, ribbon-like structureA thin and long fibrous structure
NatureHomologous chromosomes are not identical (one coming from each parent)Sister chromatids are identical (one is an exact copy of the other)
Arrangement of DNAMost condensed form of DNADNA is fifty times less condensed than chromosomes
Presence of CentromereAbsentPresent
OccurrenceFound in cells throughout their lifeFound between interphase and metaphase of cell division
DuplicationChromosomes can duplicateChromosomes cannot duplicate
Functions1. Helps in the distribution of the genetic material, the DNA from one generation to the next
2. Packaging of DNA inside the nucleus
3. Involved in protein synthesis
1. Maintains exact chromosome number from one generation to the next
2. Helping the cell to duplicate
3. Involved in metabolism and other cellular activities  

Similarities

  • Both chromosomes and chromatids carry genetic information and are made of DNA
  • Both participate in the process of cell division
  • Both are located inside the nucleus of the cell in higher organisms
  • In higher organisms, both contain a class of structural proteins called histones

Conclusion

Combining the differences and the similarities, we can conclude that a chromatid is always a part of a chromosome while the chromosome is made of DNA and proteins. The main difference between a chromosome and a chromatid is in the level of condensation. While DNA is condensed 10,000 times in a chromosome, it is condensed 50 times in a chromatid. Although both actively participate in the cell division process, the chromosome helps distribute genetic material from parent to daughter cells.  A chromatid, on the other hand, participates in the regulation of gene expression.

FAQs

Q1. Which structure during cell division is called a homologous chromosome pair?

Ans. A tetrad is a structure that consists of a pair of homologous chromosomes (having four sister chromatids) formed during meiotic cell division.

Q2. How are DNA, chromatin, chromatids, and chromosome related to each other?  

Ans. DNA is the basic genetic material of a cell having a double-stranded structure that forms the basis of chromosomes along with its packaging proteins called histones. Chromatin is a decondensed or unpacked chromosome found in a cell when not in cell division. On the other hand, a chromatid is one copy of a chromosome found after chromosome division.

Article was last reviewed on Friday, September 25, 2020

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