Q18 of 54 Page 51

Here are some statements about meiosis. State whether each of them is true or false:

i) It takes place in somatic cells.


ii) Meiosis is also called reduction division.


iii) The pairing of homologous chromosomes is called crossing over.


iv) Meiosis leads to variations which form the raw material for evolution.

(i) Given statement is false because meiosis is a reduction kind of division which take place only in germinal cells for formation of gametes. It never takes place in somatic cells.

(ii) Given statement is true because in meiosis the number of chromosomes after the meiotic division exactly becomes half of the original number. As the reduction in a number of chromosomes takes place meiosis is also called reduction division.


(iii) Given statement is false. The pairing of chromosomes is not called crossing over because both are different processes. In pairing homologous chromosomes comes near each other and pair with each other. This process is called synapsis.


Whereas in crossing over the exchange of non sister chromatids in homologous chromosomes takes place.


(iv) Given statement is true because in meiosis crossing over takes place between the non sister chromatids of homologous chromosomes due to which exchange of information takes place. Due to this exchange in information variations occur and as it takes place in the germinal cells these variations are further inherited by the future generation, so variations arising due to crossing over in meiosis lead the basis of evolution.


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