Q4)What is the genetic material?what is its importance?
Q5)What are recessive genes?
Q6)What are dominant genes?
Q7)Name the cells which possess half the number of chromosomes in human beings? (hint-germ or reproductive cells)
Q8)State the advantages of sexual reproduction?
Q9)Name any two contrasting characters noticed by Mendel in the garden pea plants.
Q10)State the ratio of plants produced in the monohybrid cross in the F1 and F2 generation?
4. The part of the cell which carries the genetic information that can be inherited is called genetic material. Example: DNA and RNA. The important function of the genetic material is to store information needed by the cell to make proteins.
5. Recessive Genes:- Those gene which are not able to express the traits carried by them in heterozygous condition & get suppressed by the dominant genes are known as recessive genes. They are expressed only in homozygous condition For Eg:- Dwarfness of pea plant is a recessive trait, genotypically represented as "tt"
6. Dominant Genes:- Those genes which are able to express the traits carried by them in homozygous as well as in heterozygous condition are known as dominant genes. For eg: Tallness of pea plant is a dominant trait represented as "TT"/"Tt".
7. Germ cells i.e sperm and egg cell possess half the number of chromosomes in human beings.
8. The major advantage of sexual reproduction is that it generates variation in the next generation and makes them more suited for the changing environment. Some genes which were lethal or disadvantageous could be lost in the genetic recombination.
9. Mendel noticed 7 contrasting characters in pea plant and two of them are
- Height: Tall and Dwarf
- Shape of seed: Round seeds and wrinkled seeds
10. The ratio of plants produced in monohybrid cross such as cross between tall and dwarf pea plant was as under:
F1: Phenotypic: All tall plants and Genotypic: All heterozygous tall
F2: Phenotypic : 3: 1 and Genotypic: 1:2:1