Biology 12th VVI Questions part – 01
Q.1. Differentiate between nucleoside and nucleotide.
Ans – Nucleoside:- (a) A nucleoside consists of a nitrogenous base covalently attached to a sugar but without the phosphate group.
(b) Several nucleoside used as antiviral or anti cancer agents.
Nucleotide:- (a) A nucleotide consists of nitrogenous base, a sugar and one to three phosphate group.
(b) Malfunctioning nucleotides are one of the main causes of all cancers known today.
Q.2. Write adaptations of wind pollinated flowers.
Ans – Some adaptations are :- (a) Small number of ovules and huge number of pollen grains. (b) it is smaller, light and dry, and not easily wetted by rain and have adaptation to make them float better like flat surfaces. (c) It is produced in enormous quantity. (d) It is inconspicuous with no colour, oudour or nectar.
Q.3. Why did Mendel select pea as his experimental material ?
Ans – Mendel selected pea as his experimental material because (a) They can be grown easily and in large numbers. (b) Their reproduction can be manipulated. (c) In pea, both organs are located in the same flower and are tightly enclosed by petals. They reproduce by self pollination. One can open the petals of flower and remove the male organ for pollination.
Q.4. Write two major functions each of testis and ovary.
Ans – Two major functions of testis and ovary are following.
Function of Testes:- (a) Spermatogensis to produce sperm, male gametes and reproductive cells. (b) Secretion of male sex hormone chiefly testosterone.
Function of ovary:- (a) Oogenesis: to produce ova, male gametes. (b) Secretion of female sex hormone, estrogen and progesterone.
Q.5. Why is haemophilia called as bleeder’s disease ?
Ans – Haemophilia is called as bleeder’s disease because a person who has haemophilia has a tendancy to bleed excessively even in minor cuts and wounds.