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