(a) State one advantage of variation to a species.
(b) What are sex chromosomes ? How many sex chromosomes are there ? Name them.
(a) State one advantage of variation to a species.
(b) What are sex chromosomes ? How many sex chromosomes are there ? Name them.
(a)
Advantages:-
1. It make every individual different from each other so that each individual has its own identity and can be easily recognisable.
(b) Sex chromosomes are chromosomes that determine whether the individual is a male or female. Though these two chromosomes pair with each other during meiosis, there is usually a very minimal homology or recombination between them, primarily because of a large difference in their genetic content and size. Often one chromosome is smaller, and appears to retain only those genes that are necessary for sex determination.
.
These genes not only give rise to the external male or female characteristics, but are responsible for the development of their reproductive organs.
There are two types of sex chromosomes
XX and XY
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.
The 22 autosomes are numbered by size. The other two chromosomes, X and Y, are the sex chromosomes.
The spread of chromosomes in a human is listed below.
(a)
Advantages:-
1. It make every individual different from each other so that each individual has its own identity and can be easily recognisable.
(b) Sex chromosomes are chromosomes that determine whether the individual is a male or female. Though these two chromosomes pair with each other during meiosis, there is usually a very minimal homology or recombination between them, primarily because of a large difference in their genetic content and size. Often one chromosome is smaller, and appears to retain only those genes that are necessary for sex determination.
.
These genes not only give rise to the external male or female characteristics, but are responsible for the development of their reproductive organs.
There are two types of sex chromosomes
XX and XY
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.
The 22 autosomes are numbered by size. The other two chromosomes, X and Y, are the sex chromosomes.
The spread of chromosomes in a human is listed below.
