GENETICS

GENETICS
1. In a cross between TTRr and ttrr, the phenotype ratio will be-

a.s:1 b.9:3:3:1 c.1:1:1:1 d.1:1

A test cross is -

a. Back cross b. Crossing over c. Monohybrid d. Dihybrid cross

3. The law of purity of gametes is also known as-

a. Law of segregation b. Law of dominance c. Law of crossing over

d. Law of unit character

4. If a heterozygous tall plant crossed with a homozygous dwarf plant, the population of the

dwarf progeny will be-

a.. 50% b. 75% c. 25% d. 100%

5. First exception to the Law of independent assortment was reported by

a. Sutton and Bovfery b. Bateson and Punnet c. Morgan d. correns

6. If the mono hybrid phenotype ratio is 1:2:1, the nature of inheritance is-

a. Co-dominance b. Incomplete dominance c. Both a &b d. Neither a nor b

7. An organism with Y Y Rr T T is a-

a. Trihybrid b. Mono hybrid c. Di hybrid d. All these

8. Crossing over results in the formation of

a. New genes b. New combinations of genes c. A new chromosome d. All these

9. The number of chiasma formations during crossing over is directly proportional to;

a. Length of the chromosome b. Distance between the genes

c. Number of genes on chromosome d. All these

10. Which of the following cross would produce a genotype ration of 1:2:1 in F2 generation?

a. AA x aa b. AA x AA c. Aa x Aa d. aa x aa

11. The ratio 1:2:1 in the off springs of hybrids illustrates the principle of-

a. Dominance b. Segregation c. Recessiveness d. Independent assortment

12. What is the ratio between the parental and recombinant phenotypes in F2 population of a

Dihybrid cross?

a. 3:1 b. 1:1:1:1 c. 9:3:3:1 d. 5:3
13. Emasculation is achieved by-

a. Removal of anthers b. Removal of carpals c. Removal of flowers

d. Removal of stigma

14. The mono hybrid test cross genotype ratio is;

a. 1:1 b. 1:1:1:1 c. 1:2:1 d. 2:1
15. If an allele is dominant, indicate the condition in which dominance becomes expressed.

a. Homozygous b. Hemizygous c. Heterozygous d. All

16. Drosophila have four pairs of homologous chromosomes. What is the number of linkage

groups in the animal?

a. 4 b. 2 c. 8 d. Data not sufficient

17. Had Mandel selected ten pairs of characters instead of seven in pea plants, he would not

have discovered the law of-

a. Unit characters b. Dominance c. Independent assortment d. segregation

18. A phenotype mono hybrid ratio is 2:1 what is the nature of inheritance?

a. Dominance b. Co-dominance c. Epistasis d. Lethal genes

19. When Mendel crossed a true breeding white strain of Pisum sativum with a hybrid red

flower strain the individuals obtained were 50% red-flowered and 50% white flowered.

This shows the genes for white is-

a. Dominant b. Co-dominant c. Recessive d. Sex linked

20. When a heterozygous offspring is crossed with a homozygous dominant plant, it is called

a. Back cross b. Test cross c. Reciprocal cross d. Special cross

21. An autosome is a chromosome-

a. That determines the sex b. Other than sex chromosome c. Both a & b

d. None of these

22. A human ovum contains-

a. XX chromosome b. XY chromosome c. Y chromosome d. X chromosome

23. If a haemophiliac woman marries a normal man, their children will be

a. Normal sons and daughters b. Carrier daughters and haemophiliac sons

c. Haemophiliac daughters and normal sons d. None of these

24. Baldness in man is a

a. Sex-linked character b. Sex-limited character c. Sex influenced character

d. Sexual character

25. For sex linked diseases human males are carriers . This statements is-

a. True b. False c. Some times true d. 25% true


ANSWERS

1.c & d 2.d & a 3.a 4.a 5.b 6.b & c 7.b 8.a & b 9.b & d 10.a 11.b 12.d 13.d &a

14.a 15.d 16.a 17.c 18.d 19.c 20.b &a 21.b 22.d 23.b 24.c 25.b