CRASH COURSE BIOLOGY: Genetic basis of inheritance

CRASH COURSE BIOLOGY

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1. Genetic basis of inheritance

1. The functional unit of heredity is

(a) chromosome (b) protein

2. The factors which represent the contrasting

pairs of character are called

(a) dominant and recessive

(b) alleles

(d) determinants

3. The first work on genetics was done by

(a) Lamarck (b) Hugo de Vries

4. Mendel’s laws were rediscovered by

(a) Lamarck, de Vries and Correns

(b) Hugo De Vries, Correns and Tschermak

(d) Hugo de Vries, Morgan and Correns

5. Mendel’s principles are related to

(a) evolution (b) reproduction

6. Mendel performed experiments on

(a) Pigeon Pea (b) Cow Pea

7. Emasculation is

(a) removing pollens grains

(b) removing stamens before anthesis

(d) removing stamens from male parent.

8. The term genetics was coined by

(a) Mendel (b) Bateson

9. The character which appears in F1

generation

in a hybrid cross is called

(a) recessive (b) dominant

10. Which of the following pairs is not of a

contrasting character?

(a) Tall and Dwarf stem

(b) Axial and Terminal flower

(d) Round and Light seed

11. The offspring of a cross between two

individuals differing in at least one set of

characters is called

(a) polyploid (b) mutant

12. Mendel selected pea as material for his

experiments because

(a) it is an annual plant with short life cycle.

(b) the flowers are naturally self-pollinated.

(d) all of these.

13. First generation after a cross is called

(a) first filial generation

(b) \(\mathrm{F}_1\) hybrid

(d) both ' \(a\) ' and ' \(b\) '

14. \(F_2\) generation is produced as result of

(a) crossing \(F_1\) individual with dominant individuals.

(b) crossing \(F_1\) individual with recessive individuals.

(d) crossing \(\mathrm{F}_1\) individuals with their dominant parents.

15. In Pisum sativum which of the following traits is dominant?

(a) White flowers

(b) Green seeds

(d) Inflated pods

16. Which is an ill correct pair in Mendelian characters?

Character Dominant Recessive

(a) Pod colour Green Yellow

(b) Seedshape Round Wrinkled

(d) Shape of pod Inflated Constricted

17. A pure tall pea plant was crossed with a pure dwarf pea plant. All the plants of \(F_1\) were found to be tall, This is due to

(a) dominance.

(b) disappearance of factor for dwarfness in \(F_1\) generation.

(d) incomplete dominance.

18. A monohybrid cross is the one in which

(a) only a single plant is involved for the experiment.

(b) a single pair of contrasting characters is considered for the cross.

(d) \(\mathrm{F}_1\) hybrid is crossed back with recessive parent.

19. In Mirabilis jalapa when two \(F_1\) pink flowered plants were crossed with each other, the \(F_2\) generation produced 40 red, 80 pink and 40 white flowering plants. This is a case of

(a) duplicate genes

(b) lethal genes

(d) epistasis.

20. For a given character, a gamete is always

(a) homozygous

(b) pure

(d) heterozygous

21. How would you test a pea plant whether it is a pure or hybrid for tallness?

(a) Cross it with another tall pea plant of unknown genotype.

(b) Cross it with a pure tall pea plant.

(d) Cross it with any pea plant

22. A cross between \(\mathrm{F}_1\) hybrid and its parent is

(a) back cross

(b) reciprocal cross

(d) dihybrid cross

23. Test cross is a cross between

(a) hybrid \(X\) dominant parent (Tt \(X\) IT)

(b) hybrid \(X\) recessive parent ( \(\mathrm{Tt} X\) tt)

(d) hybrid \(X\) unknown parent

24. A cross between an individual with unknown genotype for a trait with recessive plant for that trait is

(a) Back cross

(b) Reciprocal cross

(d) Monohybrid cross

25. Genetically identical progeny is produced when individuals

(a) perform cross fertilization.

(b) produces identical gametes.

(d) exhibit sexual reproduction.

26. Tall plant with round seeds is crossed with dwarf plant having wrinkled seeds. This type of cross is

(a) dihybrid

(b) monohybrid

(d) back cross

27. Genes do not occur in pairs in

(a) zygote

(b) somatic cell

(d) gametes

28. Pisum sativum is

(a) strictly a self fertilizing plant.

(b) naturally self fertilizing but cross fertilizable plant.

(d) strictly cross fertilizing plant.

29. The phenotypic ratio in incomplete dominance is

(a) \(3: 1\)

(b) \(1: 2: 1\)

(d) \(1: 1\)

30. In a dihybrid cross, \(\mathbf{F}_2\) generation offsprings show four different phenotypes while the genotypes are

(a) Six

(b) Nine

(d) Sixteen

31. Pea plant with double hybrid yellow round seeds ( \(\mathrm{YyRr}\) ) is crossed with pea plant having single hybrid green round seeds (yyRc). The progeny shall be

(a) \(3: 3: 1: 1\)

(b) \(1: 1: 1: I\)

(d) \(3: 1: 3: 1\)

32. The ratio of phenotypes in \(F_2\) of a monohybrid cross is

(a) \(3: 1\)

(b) \(1: 2: 1\)

(d) \(2: 1\)

33. Heterozygous tall plant is selfed. It produced both tall and dwarf plants. This confirmed Mendel's law of

(a) dominance

(b) segregation

(d) incomplete dominance

34. ' \(R\) ' is dominant red flower trait while ' \(r\) ' is recessive white flower trait. Heterozygous \(\mathrm{Rr}\) (red) is crossed with homozygous red (RR) flowered plant. In all 64 offsprings are produced. Number of white flowered plants is

(a) 64

(b) 32

(d) 0

35. Heterozygous tall (Tt) is crossed with homozygous tall (IT). Percentage of heterozygous tall in the progeny would be.

(a) \(25 \%\)

(b) \(50 \%\)

(d) \(100 \%\)

36. Hybrid pea plant with yellow round seeds (YyRr) is self pollinated. Phenotypic ratio of next generation would be

(a) \(13: 3\)

(b) \(9: 7\)

(d) \(9: 3: 3: 1\)

37. In a cross between heterozygous tall (Tt) and homozygous tall (IT), there is a progeny of 12 . How many of them would be tall?

(a) 8

(b) 10

(d) 12

38. In red-white flowered cross of Mirabilis jalapa, \(\mathbf{F}_2\) generation has red, pink and white flowered plants in the ratio of

(a) \(1: 2: 1\)

(b) \(1: 0: 1\)

(d) \(1: 1: 2\)

39. The gene which controls many characters is called

(a) Codominant gene

(b) Polygene

(d) Multiple gene

40. In an experiment on pea plant, pure plants with yellow round seeds (YYRR) were crossed with plants producing green wrinkled seeds (yyrr). What will be phenotypic ratio of \(F_1\) progeny?

(a) 9 yellow round : 3 round green : 3 wrinkled yellow: 1 green wrinkled

(b) All yellow round

(d) All wrinkled green.

41. A pea plant with yellow and round seeds is crossed with another pea plant with green and wrinkled seeds produced 51 yellow round seeds and 49 yellow wrinkled seeds. Genotype of plant with yellow round seeds must be

(a) YYRr

(b) \(\mathrm{YyRr}\)

(d) YYRR

42. In a cross, 45 tall and 14 dwarf plants were obtained. Genotype of parents was

(A) IT \(x\) IT

(B) IT \(x\) Tt

(D) IT \(x\) tt

43. Tallness (T) is dominant over dwarfness (t) while red flower colour \((\mathrm{R})\) is dominant over white colour (r). A plant with genotype TtRr is crossed with plant of genotype ttrr. Percentage of progeny having tall plants with red flower

(a) \(25 \%\)

(b) \(50 \%\)

(d) \(100 \%\)

44. "Gametes are never hybrid". It is a statement of law of

(a) dominance

(b) segregation

(d) unit character

45. Inheritance of skin colour in humans is an example of

(a) Point mutation

(b) Polygenic inheritance

(d) Chromosomal aberration

46. Blood grouping in humans is controlled by

(a) 4 alleles in which \(\mathrm{A}\) is dominant

(b) 3 alleles in which \(\mathrm{AB}\) is co-dominant

(d) 3 alleles in which \(\mathrm{A}\) is dominant

47. Genes located on same locus but show more than two different phenotypes are called

(a) polygenes

(b) multiple alleles

(d) pleiotropic genes

48. When phenotypic and genotypic ratio is the same, then it is an example of

(a) Incomplete dominance

(b) Cytoplasmic inheritance

(d) Incomplete or Co-dominance

49. When two genes control single character and have cumulative effect, the ratio is

(a) \(1: 1: 1: 1\)

(b) \(1: 4: 6: 4: 1\)

(d) \(1: 6: 15: 20: 15: 6: 1\)

50. When single gene produces two effects and one of it is lethal, then ratio is

(a) \(2: 1\)

(b) \(1: 1\)

(d) \(1: 1: 1: 1\)

Next: 2. Gene : it’s nature, expression and regulation ►