Heredity and genetics objective questions and answers

Heredity and genetics objective questions and answers
Genetics Questions and Answers
Biology questions and answers Genetics Heredity

1. An organism with two identical alleles of a gene in a cell is called
(a) homozygous
(b) dominant
(c) heterozygous
(d) hybrid
Ans. (a)

2. When an allele fails to express itself in F1 generation in the presence of other allele, the former is said to be
(a) recessive
(b) codominant
(c) complementary
(d) epistatic
Ans. (a)



3. Which of Mendel’s procedures differed from those of his predecessor and contributed most of his success?
(a) He observed many characteristics of each trait
(b) He observed distinct inherited traits
(c) He quantitatively analyzed his data
(d) He kept breeding records
Ans. (c)
4. Mendel crossed a pure white flowered recessive pea plant with a dominant pure red flowered plant. The first generation of hybrids from the cross should show
(a) 50% white flowers and 50% red flowers
(b) all red flowered plants
(c) 75% red flowered and 25% red flowered plants
(d) all white flowered plants
Ans. (b)

5. If a heterozygous tall plant is crossed with a homozygous dwarf plant, the proportion of dwarf progeny will
(a) 50%
(b) 75%
(c) 100%
(d) 25%
Ans. (a)

6. Which genotype represents a true dihybrid condition?
(a) Tt Rr
(b) tt rr
(c) Tt rr
(d) Tt RR
Ans. (a)

7. When a true breeding tall plant is crossed with a true breeding short plant and the F1 produced is self pollinated to produce F2 ratio of true breeding tall and true breeding short plant in F2 will be
(a) 1:2
(b) 1:1
(c) 2:1
(d) 1:3
Ans. (b)

8. The cross used to ascertain whether the plant is homozygous or heterozygous is
(a) linkage cross
(b) reciprocal cross
(c) back cross
(d) monohybrid cross
Ans. (c)

9. The results of a test cross reveal that all the offspring resemble the parent being tested. This parent must be
(a) heterozygous
(c) recessive
(b) homozygous
(d) haploid
Ans. (b)

10. Chromosome theory of heredity was formulated for the first time on the basis of following observation:
(a) Chromosomes exhibiting segregation and independent assortment during meiosis
(b) Chromosomes being main structure in nucleus
(c) Determination of sex through sex chromosomes
(d) A fixed number of chromosomes in each cell of an organism
Ans. (a)

11. Which chromosome set is found in male grasshopper?
(a) XY
(b) X
(c) YY
(d) XX
Ans. (b)

12. Two bacteria found to be very useful in genetic engineering experiments are
(a) Nitrosomonas and Kiebsiella
(b) Escherichia and Agrobacterium
(c) Nitrosomonas and Azotobacter
(d) Rhizobium and Diplococcus
Ans. (b)

13. Which one of the following mutations is not hereditary?
(a) Gametic
(b) Zygotic
(c) Somatic
(d) Genetic
Ans. (c)

14. The reason why some mutations, which are harmful, do not get eliminated from gene pool is that
(a) they are recessive and carried by heterozygous individuals
(b) they are dominant and show up more frequently
(c) genetic drift occur because of a small population
(d) they have future survival value
Ans. (a)

15. Mutations are generally
(a) recessive
(b) codominant
(c) incompletely dominant
(d) dominant
Ans. (a)

16. Mutations are usually induced by
(a) gamma rays
(b) alpha rays
(c) beta rays
(d) visible light
Ans. (a)

17. Gene mutation is caused
(a) due to reproduction
(b) due to changes in the sequence of nitrogen bases
(c) due to linkage
(d) due to changes in the sequence of genes in DNA
Ans. (b)

18. Point mutation is
(a) loss of gene
(b) change in a base of gene
(c) addition of a gene
(d) deletion of a segment of gene
Ans. (b)

19. Sex chromosomes may be found in
(a) unisexual plant
(b) unisexual flower
(c) monocarpic plant
(d) intersexual plant
Ans. (a)

20. Which one of the following is the sex linked character in human inheritance?
(a) Diabetes insipidus
(b) Colour-blindness
(c) Breast in females
(d) Beard in males
Ans. (b)

21. Human offspring would be female, if 23rd pair of chromosome in zygote is
(a) YY
(b) XY
(c) XX
(d) XYY

Ans. (c)
22. Autosomes in humans are
(a) 22 pairs
(b) 23 pairs
(c) 43 pairs
(d) 11 pairs
Ans. (a)

23. Barr body represents
(a) heterochromatin in male and female cells
(b) one of the two X-chromosomes in somatic cells of female
(c) Y-chromosome in somatic cells
(d) all heterochromatin in female cells
Ans. (b)

24. The identical twins are born when
(a) one ovum is fertilised by one sperm
(b) one ovum is fertilised by two sperms
(c) two ova are fertilised by two sperms
(d) two ova are fertilised by two sperms
Ans. (a)
25. Down’s syndromesis due to
(a) nondisjunctin of chromosomes
(b) crossing over between genes
(c) linkage of genes
(d) sex linked inheritance
Ans. (a)

26. The first hormone artificially produced by culturing bacteria is
(a) insulin
(b) thyroxine
(c) testosterone
(d) adrenalin
Ans. (a)


27.The first successfully cloned mammal that gained world-wide publicity was
(a) Molly, a sheep
(b) Polly, a sheep
(c) Chance, a bull
(d) Dolly, a sheep
Ans. (d)


28. Producing a ‘giant mouse’ in the laboratory was
possible through
(a) gene mutation
(b) gene duplication
(c) gene synthesis
(d) gene manipulation
Ans. (d)

29. One of the following is transgenic of organisms
(a) Holly sheep and Flavr savr tomato
(b) Holly sheep and Cotton Bt
(c) Dolly sheep and Cotton Ct
(d) Flavr savr tomato and Cotton Bt
Ans. (d)
30. Which one of the following scientists got the Nobel Prize for his invention polymerase chain reaction (PCR)?
(a) F Sanger
(b) Paul Berg
(c) Alec Jeifreys
(d) Kary B. Mullis
Ans. (d)