Advertisements
Advertisements
प्रश्न
Describe the structure of sex chromosomes with the help of labelled diagram.
Advertisements
उत्तर
Structure of X and Y chromosomes:
- The x chromosome is straight, rod-like, and longer than the Y chromosome.
- The x chromosome is metacentric, while the Y chromosome is acrocentric.
- The x chromosome has a large amount of euchromatin (extended region) and a small amount of heterochromatin (highly condensed region).
- Euchromatin has a large amount of DNA material, hence the X chromosome is genetically more active.
- The y chromosome has a small amount of euchromatin and a large amount of heterochromatin, hence it is genetically less active or inert.
- Both X and Y chromosomes show homologous and non-homologous regions.
- Homologous regions show similar genes while non-homologous regions show dissimilar genes.
- Crossing over occurs only between homologous regions of X and Y chromosomes.
- The non-homologous region of the X chromosome is longer and contains more genes than that of a non-homologous region of the Y chromosome.
- X-linked genes are present on the non-homologous region of the X-chromosome while Y-linked genes are present on the non-homologous region of the Y-chromosome.
संबंधित प्रश्न
The Chromatin material is formed forms of ______.
Choose the correct answer:
Chromosomes number is halved in ____________
Choose the correct answer:
A 'V' shaped chromosomes has to _____________
What are chromosomes?
Enumerate the various changes that occur in the nucleus of the cell during prophase.
Give Reasons for the following
The meiosis is called reductional division
Name the following:
A specific part of a chromosome that determine hereditary characteristics.
Nullisomy is represented by ______.
Normally, genes occur in a pair of chromosome, but genes of X and Y chromosomes shows different gene loci indicating ______.
Rewrite the correct form of the statement by changing the first or last word only:
Duplicated chromosomes remain attached at a point termed as centrosome.
