Continuity of Life (Multiple Choice Questions and Answers)

Continuity of Life

Multiple Choice Questions and Answers

1. In monohybrid crosses, absence of complete dominance is indicated by F1 plants that are intermediate in appearance and this can be further confirmed if the phenotypic and genotypic ratio in F2 is

(a) 1:1

(b) 1:2:1

(c) 8:1

(d) 2:1:1

Answer: (b) 1:2:1

2. Five out of 20 plants obtained by selfing a red flowered plant where having white flowers. This is an indication that plant is

(a) homozygous

(b) heterozygous

(c) homogenous

(d) heterogenous

Answer: (b) heterozygous

3. Mendelian recombinations are due to

(a) independent assortment of genes

(b) linkage of genes

(c) mutation

(d) dominance

Answer: (a) independent assortment of genes

4. Blue colour in human is recessive to brown eye colour. The expected children of a marriage between a blue eyed women and brown eyed man who had blue-eyed mother would be

(a) all blue eyed

(b) all brown eyed

(c) one blue eyed and one brown eyed

(d) all black eyed

Answer: (c) one blue eyed and one brown eyed

5. Pure tall pea plant can be distinguished from a hybrid tall pea plant by

(a) measuring its height

(b) gibberellin treatment

(c) selfing and noting that all progeny are tall

(d) selfing and noting that all progeny are short

Answer: (c) selfing and noting that all progeny are tall

6. In crossing self fertilised plants the flowers are first emasculated. Which organ of the plants is removed in this process?

(a) stigma

(b) anthers

(c) ovules

(d) sepals

Answer: (b) anthers

7. There has been much emphasis on the conservation of wild relatives of cultivated plants because wild plants

(a) grow better than cultivars

(b) are needed to understand the origin of cultivated plants

(c) serve as valuable fodder plants

(d) carry many useful genes which are lost in cultivated plants

Answer: (d) carry many useful genes which are lost in cultivated plants

8. The first attempt to show linkage in plants was done in

(a) Pisum sativum

(b) Lathyrus odoratus

(c) Zea mays

(d) Oenothera lamarckiana

Answer: (b) Lathyrus odoratus

9. If a heterozygous tall plant is crossed with homozygous dwarf plant, the proportion of dwarf progeny will would be

(a) 50%

(b) 25%

(c) 75%

(d) 10%

Answer: (a) 50%

10. Sexually reproducing organisms contribute to their off

(a) 1/2 of their genes

(b) all the genes

(c) 1/4 of their genes

(d) double the number of genes

Answer: (a) 1/2 of their genes

11. The contrasting pairs of characters in Mendelian crossing are called

(a) alleles

(b) heteromorphs

(c) gene loci

(d) paramorphs

Answer: (a) alleles

12. Mendel worked in

(a) 17th century

(b) 18th century

(c) 19th century

(d) 20th century

Answer: (c) 19th century

13. Pea plants were most suitable than cattle for Mendel’s experiment because

(a) there were no breeding records of cattles

(b) pea plants can be self fertilized

(c) cattle are not is it maintain

(d) all pea plants have 2X chromosomes and fewer genetic traits

Answer: (b) pea plants can be self fertilized

14. An individual with two identical members of a pair of genetic factors is called

(a) heteromorphic

(b) heterozygote

(c) homomorphic

(d) homozygote

Answer: (d) homozygote

15. A red flowered pea plant is crossed with the white flowered pea plant. F1 is red. Then white flower colour is

(a) recessive

(b) dominant

(c) unexpressive

(d) non-genetic

Answer: (a) recessive

16. A plant is heterozygous and is designated Bb, it produces two kinds of gametes B and b. The probability of b gamete fertilizing B or b is

(a) 1/2

(b) 1/1

(c) 0/1

(d) 1/4

Answer: (b) 1/1

17. If a plant heterozygous for tallness is selfed, the F2 generation has both tall and dwarf plants. This proves the principle of

(a) dominance

(b) segregation

(c) independent assortment

(d) purity of gametes

Answer: (b) segregation

18. What will be the genetic constitution of the offspring of a cross of individual heterozygous (Aa) for an allele

(a) all AA

(b) all aa

(c) 1/2 AA, 1/2 aa

(d) 1/4AA, 1/2 Aa, 1/4aa

Answer: (d) 1/4AA, 1/2 Aa, 1/4aa

19. The type of cross between parents differing in only one character is called

(a) dihybrid cross

(b) monohybrid cross

(c) reciprocal cross

(d) trihybrid cross

Answer: (b) monohybrid cross

20. The plants are considered to be true breeding when

(a) all the plants of the parental generation resemble each other

(b) the progeny occupies less space

(c) the progeny may show genetic variability which may finally be utilised for evolving a better type

(d) the progeny is free of disease

Answer: (a) all the plants of the parental generation resemble each other

21. Which of Mendel’s procedures differed from those of his predecessors and contributed most to success?

(a) He quantitatively analysed his data

(b) He kept breeding records

(c) He observed distinct inherited traits

(d) He observed many characteristics for each trait

Answer: (c) He observed distinct inherited traits

22. Two allelic genes are located on

(a) the same chromosome

(b) two homologous chromosomes

(c) two non- homologous chromosomes

(d) any two chromosome

Answer: (b) two homologous chromosomes

23. F1 plants are

(a) heterozygous

(b) homozygous

(c) hemizygous

(d) dizygous

Answer: (a) heterozygous

24. The percentage of ab gametes produced by Aa Bb parent will be

(a) 12.5

(b) 25

(c) 50

(d) 75

Answer: (b) 25

 25. Gregor Mendel was born in

(a) Britain

(b) Austria

(c) Russia

(d) Czechoslovakia

Answer: (d) Czechoslovakia

 26. How many pairs of contrasting characters in pea pod with chosen by Mendel?

(a) 2

(b) 3

(c) 4

(d) 7

Answer: (b) 3

27. A cross between F1 hybrid and a recessive is parent gives the ratio of

(a) 3:1

(b) 1:1

(c) 2:1

(d) 4:1

Answer: (b) 1:1

 28. If a homozygous tall male plant (dominant) is crossed with the homozygous dwarf male plant (recessive), genotype of endosperm would be

(a) ttt

(b) ttT

(c) TTt

(d) TTT

Answer: (c) TTt

 29. Organisms phenotypically similar but genotypically different are said to be

(a) multizygous

(b) homozygous

(c) heterozygous

(d) monozygous

Answer: (c) heterozygous

 30. A tobacco plant which is heterozygous for albinism (a recessive character) is self pollinated. If 1200 seeds are subsequently germinated, how many of the seedlings would have the parental genotype?

(a) 300

(b) 600

(c) 900

(d) 1200

Answer: (b) 600

 31. In hybridization Tt x tt gives rise to progeny in the ratio of

(a) 1:1

(b) 1:2

(c) 2:1

(d) 1:2:1

Answer: (a) 1:1

32. Hybrid with similar genotypes are called

(a) hybrid

(b) homozygous

(c) allele

(d) clone

Answer: (d) clone

33. How many types of genetically different gametes would be produced by a heterozygous plant having the genotype AABbCc?

(a) 2

(b) 4

(c) 6

(d) 9

Answer: (b) 4

34. Heterozygotes have

(a) only dominant genes

(b) only recessive genes

(c) both a and b

(d) none of the above

Answer: (c) both a and b

35. A test cross distinguishes between

(a) two homozygous forms

(b) a homozygous dominant and the heterozygous form

(c) two heterozygous forms

(d) a homozygous recessive and the heterozygous form

Answer: (b) a homozygous dominant and the heterozygous form

36. When a heterozygous dominant is crossed with homozygous recessive, then the ratio in the next filial generation will be

(a) 1:2

(b) 2:1

(c) 3:1

(d) 1:1

Answer: (d) 1:1

37. When a plant of F1 generation is crossed with homozygous dominant parent, it is known as

(a) simple cross

(b) test cross

(c) back cross

(d) special cross

Answer: (c) back cross

38. In Mendelism linkage is not observed due to

(a) mutation

(b) independent assortment

(c) synapsis

(d) crossing over

Answer: (b) independent assortment

39. Heterozygous tall plant produce tall and dwarf plants after selfing. This confirms Mendel’s law of

(a) dominance

(b) segregation

(c) incomplete dominance

(d) independent assortment

Answer: (b) segregation

40. Pea plants with round and yellow (RRYY) and wrinkled and green (rryy) seeds were crossed. The F1 generation would be

(a) round and wrinkled

(b) round and yellow

(c) round and green

(d) wrinkled and yellow

Answer: (b) round and yellow

41. Branch of biology dealing with heredity is

(a) genetics

(b) eugenics

(c) euthenics

(d) cytology

Answer: (a) genetics

42. Which is correct about the characters chosen by Mendel?

(a) terminal pod is dominant

(b) constricted pod is dominant

(c) green coloured pod is dominant

(d) tall plants are recessive

Answer: (c) green coloured pod is dominant

 43. Probability of four sons to a couple is

(a) 1/4

(b) 1/8

(c) 1/16

(d) 1/32

Answer: (c) 1/16

44. A gamete normally contains

(a) two alleles of a gene

(b) one allele of a gene

(c) many alleles of a gene

(d) all alleles of a gene

Answer: (b) one allele of a gene

45. Which of the following traits of garden pea studied by Mendel was a recessive feature?

(a) axial flower position

(b) green seed colour

(c) green pod colour

(d) round seed shape

Answer: (b) green seed colour

46. Who gave the term genotype?

(a) Bateson

(b) Mendel

(c) Johannsen

(d) Davenport

Answer: (c) Johannsen

47. The offspring of AAbb x aaBB is crossed with aabb. The genotype ratio of progeny will be

(a) 9:3:3:3:1

(b) 1:2:1

(c) 1:1:1:1

(d) 4:1

Answer: (c) 1:1:1:1

48. Which variations are temporary and are not connected with the last or next generation?

(a). Hereditary variations

(b) Environmental variations

(c) Discontinuous variations

(d) Continuous variations

Answer: (b) Environmental variations

49. Out of seven characters in pea plant studied by Mendel, the number of flower based characters was

(a) 1

(b) 4

(c) 3

(d) 2

Answer: (d) 2

50. Phenotypic dihybrid ratio in F2 generation is

(a) 1:3

(b) 9:3:3:1

(c) 1:1:1:1

(d) 1:2:1

Answer: (b) 9:3:3:1