Genetics MCQs Part III

1) A colour blind man marries a normal woman whose father was colour blind. What percentage of children would be expected to be colour blind?
a) 25%
b) 50%
c) 75%
d) 100%

2) Mendel did not get any linkage in his experiments on pea. One of the reasons was that
a) He did not keep an exact record
b) There is no linkage in pea
c) He did not have means to detect linkage
d) All the seven characters selected by him were present on different chromosomes or showed 50% cross-over

3) Crossing over occurs between
a) Two non-sister chromatids of a homologous pairs of chromosomes
b) Two chromatids of any chromsomes
c) Two chromatids of same chromosome
d) All the foregoing

4) Neurospora crassa is widely used in genetical studies because
of all the following except one

a) It is a haploid plants and mutations can be easily detected
b) It can be easily cultured
c) Life-cycle is short
d) Spores are not affected by mutagens

5) Mendelian recombinations are due to
a) Mutations
b) Linkage
c) Crossing over
d) Independent assortment of characters

6) Which one of the following characters in man is controlled by a recessive

a) Colour blindness
b) Woolly hair
c) Brachydactyly
d) Curly hairs

7) A normal plant suddenly started reproducing parthenogenetically. The
number of chromosomes of the second generation as compared to the parent
will be

a) One half
b) One fourth
c) Same
d) Double

8) Plotting of specific genes on the chromosome is known as
a) Chromosome map
b) Linkage map
c) Genetic map
d) All the above

9) In flowering plants meiosis occurs at the time of
a) Germination of seed
b) Formation of endosperm
c) Formation of the embryo
d) Formation of pollen

10) A child is born with an extra chromosome in each of its cells. This condition
is the result of

a) Synapsis
b) Crossing over
c) Non-disjunction
d) Disjunction

11) The number of Barr bodies in Turner syndrome is
a) 0
b) 1
c) 2
d) 3

12) In a certain gene mutation, adenine is replaced by guanine. It is known as
a) Substitution
b) Point mutation
c) Transition
d) Transversion

13) In transversion
a) Purine is replaced by another purine
b) Purine is replaced by pyrimidine or vice versa
c) Some nitrogen bases are eliminated from a gene
d) Some nitrogen bases are added in a gene

14) Alkaptonurics excrete an excess of
a) Urine
b) Albumen
c) Malic acid
d) Homogentisic acid

15) Colour blindness is more likely to occur in males than females because
a) The genes for this character are located on the X-chromosomes
b) The trait is dominant in males and recessive in females
c) Some males suffer from deficiency of vitamin A
d) The Y-chromosome of males have the genes for distinguishing colours

16) An animal where the male carries half the chromosomes present in the female

a) Amoeba
b) Gorilla
c) Honey bee
d) Geometrid moth

17) XX-XO sex chromosome complement occurs in
a) Cockroaches
b) Honey bees
c) Human beings
d) Chimpanzees

18) Which one is homogametic?
a) Human child
b) Human embryo
c) Human male
d) Human female

19) Crossing over occurs at the
a) Four strand stage
b) Three strand stage
c) Two strand stage
d) Single strand stage

20) In Neurospora, both recessive and dominant alleles express their
effect because

a) Two genes control each character
b) There are two alleles for each character
c) The organism contains only one allele for a gene
d) Each gene has only one allele

21) The term mutation was coined by
a) Morgan
b) Beadle and Tatum
c) Hugo de Vries
d) H.J. Muller

22) Mutations were first reported by De Vries in
a) Pea
b) Datura
c) Oenothera lamarckiana
d) None of the above

23) Who induced mutations by X-ray irradiation in fruit fly for the first

a) De Vries
b) H.J. Muller
c) Morgan
d) Bateson

24) If a part of a chromosome gets separated and reattached in the reverse position
to the same chromosome, the mutation is called

a) Inversion
b) Transversion
c) Translocation
d) Gene mutation

25) is
another term for

a) Transition
b) Transversion
c) Reciprocal translocation
d) None of the above

26) Mutations do not result in
a) The death of the organism
b) Better progeny
c) A change in the genetic constitution of the cell
d) Hybrid vigour

27) Aneuploidy is the term applied for
a) Gene mutations
b) Chromosomal mutation
c) Chromosomal mutations involving the addition or loss of one or more chromosome
d) Chromosomal mutation involving the addition of one or more complete set of chromosome

28) A monosomic organism can best be represented as
b) 2n-2
c) 2n+1+1
d) ()

29) A flower was fertilised by pollen grains having the constitution
(n-1). If the ovules are normal, which of the following is applicable
to the seeds so produced?

a) Allopolypoidy
b) Monosomy
c) Nullisomy
d) Both A and B

30) A mutations changes the original base sequence of DNA, GATAGCG
to a new sequence GGTAGCG. What is the type of mutations?

a) Transition
b) Transversion
c) Translocation
d) Inversion

31) A classical example of allopolypoidy is
a) Brassica
b) Raphano-brassica
c) Raphanus
d) All the above

32) The first manmade cereal Triticale has been developed from a
cross between

a) Wheat and Oat
b) Wheat and Maize
c) Maize and Rice
d) Wheat and Rye

33) Mutations are
a) Always useful
b) Seldom useful
c) Always harmful
d) Either useful or harmful

34) When chromosomes sets are present in multiples of
the condition is termed

a) Diploidy
b) Haploidy
c) Euploidy
d) Aneuploidy

35) The smallest segment of a gene which can undergo mutation
is called

a) Muton
b) Recon
c) Cistron
d) Interferon

36) The mutations which prove fatal for the organism are called
a) Spontaneous
b) Induced
c) Deleterious
d) Lethal

37) A pleiotropic mutation is the one which
a) Affects one character at a time
b) Affects many characters at a time
c) Is always lethal
d) Easily gets preserved in natural conditions

syndrome is a typical case of

a) Trisomy
b) Nullisomy
c) Gene mutation
d) Monosomy

39) It is a common observation that some insects have developed
resistance to DDT. The reason may be attributed to

a) Poor quality of DDT
b) Genetic recombination
c) Genetic mutation
d) Hybrid vigour

40) Datura is a classical example of study of
a) Monosomics
b) Trisomics
c) Triploids
d) Nullisomics

41) Which one is a hexaploid species of wheat?
a) Triticum monococcum
b) T.aestivum
c) T. durum
d) T. turgidum

42) Colchicine interferes in
a) Spindle organisation
b) DNA replication
c) Chromosome condensation
d) Polyploidy

43) Haploids are used for researches because
a) They contain only one chromosome
b) They contain two sets of chromosomes
c) They contain three sets of chromosomes
d) They contain only one set of chromosomes

44) Male sterile lines were first discovered in
a) Wheat
b) Maize
c) Onion
d) Sunflower

45) The scientist who first discovered cytoplasmic inheritance

a) Correns
b) Rhoades
c) Mendel
d) Morgan

46) Shell coiling in Limnaea is an example of
a) Maternal inheritance
b) Biparental inheritance
c) Predetermination
d) Dauermodification

47) Kappa particles are present in
a) Plastids
b) Mitochondria
c) Plasmids
d) Cytoplasm

48) The killer chemical secreted by kappa particles is
a) Secretin
b) Paramecin
c) Plasmon
d) Poky

49) Cytoplasmic inheritance differs from nuclear inheritance
in the absence of

a) Similarity of reciprocal crosses
b) Biparental contribution
c) Effect on backcrossing
d) All the above

50) A genome represents a
a) Haploid chromosome set
b) Complete chromosome set
c) Diploid chromosome set
d) All the genes present in the population

51) Chromosomes are formed by
a) DNA, RNA and proteins
b) DNA only
c) RNA only
d) Proteins

52) Chromosomes found in prolonged prophase state in salivary
glands of Drosophila are

a) Lampbrush chromosomes
b) B-chromosomes
c) Heterochromosomes
d) Polytene chromosomes

53) An octamer of 4 histones complexes with DNA to form a
a) Endosome
b) Nucleosome
c) Mesosome
d) Centromere

54) Nucleosome core is made of
a) H1, H2A, H2B, and H3
b) H1, H2a, H2B, H4
c) H1, H2a, H2B, H3 and H4
d) H2A, H2B, H3 and H4

55) Balbiani rings occur in
a) Polytene chromosomes
b) Lampbrush chromosomes
c) Polysomes
d) Heterosomes

56) Allosomes are the name of
a) Sex chromosomes
b) Swellings on the chromosomes
c) Chromosomes other than the ones which determine sex
d) Nucleolus organising regions of chromosomes

57) A family of five daughters only is expecting sixth
issue. The chance of its being a son is

a) Zero
b) 25%
c) 50%
d) 100%

58) In human beings 45 chromosomes/single X/XO abnormality


59) A webbed neck is characteristic of
a) XXX
b) YY
c) XXY
d) XO

60) Ovum producing Klinefelter’s syndrome shall have chromosome number
a) 21
b) 22
c) 23
d) 24

61) Both husband and wife have normal vision though
their fathers were colour blind. The probability
of their doughter becoming colour blind is

a) 0%
b) 25%
c) 50%
d) 75%

62) Haemophilia is more common in males because it
is a

a) Recessive character carried by the Y- chromosome
b) Dominant character carried by the Y- chromosome
c) Dominant trait carried by the X- chromosome
d) Recessive trait carried bythe X- chromosome

63) Improvement of mankind genetically is
a) Euthenics
b) Epigenetics
c) Eugenics
d) Human genetics

64) A colour blind girl is rare because she will be
born only when

a) Her mother and maternal grand father were colour blind
b) Her father and maternal grandfather were colour blind
c) Her mother is colour blind and father has normal vision
d) Parents have normal vision but grand parents were colour blind

65) A single recessive trait which can express its
effect should occur on

a) Any autosome
b) Any chromosome
c) The X-chromosome of a female
d) the X-chromosome of a male

66) Mongolism, syndrome
syndrome are due to

a) Allosomal abnormalities
b) Autosomal abnormalities
c) Both A and B
d) None of these

67) A colour blind mother and normal father would

a) Colour blind sons and normal.carrier daughters
b) Colour blind sons and daughters
c) All colour blind
d) All normal

68) Linkage in plants was first shown in
a) Zea mays
b) Lathyrus odoratus
c) Oenothera lamarckiana
d) Pisum sativum

69) The plant in which the chromosomal basis of sex determination was discovered
first is

a) Rumex
b) Melandrium
c) Coccinia
d) Sphaerocarpus

70) A dark stained body near the nuclear envelope from a buccal cavity cell

a) XX
b) XY
c) XXX
d) XYY

71) Phenylketonuria (PKU) is inherited disease that is characterised by
a) Elimination of gentisic acid in urine
b) Increased occurrence of phenylalanine in blood and tissues
c) Elimination of sugar in urine
d) Decrease in phenylalanine in blood and tissues

72) Muller was awarded the Nobel Prize in 1946 for his work on
a) Protein synthesisv
b) Chemistry of nucleic acids
c) Cancer
d) X-ray induced mutations

73) Mutations are induced mostly by
a) UV radiations
b) Beta rays
c) Alpha rays
d) Gamma rays

74) Gene mutation is due to
a) Change in the base sequence
b) Change in the sequence of cistrons in DNA
c) Linkage and crossing over
d) Random segregation

75) Mutations are
a) Always harmful
b) Rarely useful
c) Mostly useful
d) Always useful

76) The terms cistron, recon and muton were coined by
a) Ingram
b) Lederberg
c) Benzer
d) Bateson

77) Chromosome pairing in salivary gland chromosomes resembles zygotene
pairing in that

a) It is followed by crossing over
b) It can occur in nonhomologous segments
c) Pairing occurs in homologous regions only
d) It is followed by reductional separation

78) Two dominant nonallelic ganes are 50 map units apart. The linkage is
a) Cis type
b) Trans type
c) Complete
d) Absent/Incomplete

79) One barr body is found in a man of genotype
a) XY
c) XXY
d) XX

80) A colour blind man has a colour blind sister but normal brother. The
phenotype of parents is

a) Normal father and colour blind mother
b) Both parents are normal
c) Both parents are colour blind
d) Father colour blind and mother carrier

81) Who studied sex-linked inheritance for first time?
a) Morgan
b) Khorana
c) Pasteur
d) Von Helmont

82) Mr. Kapoor has Bb autosomal gene pair and d allele sex-linked. What
shall be proportion of Bd in sperms?

a) Zero
b) ½
c) ¼
d) 1/8

83) In a cross between genotype ab and + +, 650 out of 1000 individuals
were of parental type. The distance between A and B is

a) 35 map units
b) 45 map units
c) 15 map units
d) 30 map units

84) A fruitfly exhibiting both male and female traits is a
a) Heterozygous
b) Gynandromorph
c) Hemizygous
d) Gynander

85) A man with enlarged breasts, sparse body hair and XXY chromosome complement
is suffering from

c) Klinefelter’s syndrome
d) Superfemale

86) Genes located on the Y-chromosome are
a) Mutant genes
b) Sex-linked genes
c) Autosomal gense
d) Holandric genes

87) The point at which polytene chromosomes appear attached is the
a) Centriole
b) Chromocentre
c) Chromomere
d) Centromere

88) The man-made cereal is
a) Triticum
b) Hordeum
c) Triticale
d) Eleusine

89) The substance which causes a definite change in genes is called a
a) Mutagen
b) Toxin
c) Cytotoxin
d) Alkaloid

90) Lampbrush chromosomes are seen during
a) Meiotic metaphase
b) Mitotic metaphase
c) Mitotic prophase
d) Meiotic prophase

91) Which one is a triploid?
a) Mango
b) Wheat
c) Orange
d) Banana

92) The Nobel Prize for transposable DNA elements was given to
a) Muller
b) Mc Clintock
c) Morgan
d) Kornberg

93) Which pteridophyte has the maximum chromosome number?
a) Ophioglossum reticulatum
b) Azolla pinnata
c) Lycopodium cernuum
d) Selaginella apus

94) Taylor demonstrated chromosome replication to be semiconservative in
a) Vicia faba
b) HeLa cell
c) Pea
d) Mouse liver cell

95) Lampbrush chromosomes were described by
a) Balbiani
b) Benzer
c) Dupraw
d) Ruckert

96) The occurrence of a free martin is due to
a) Sex reversal by the gene
b) Environmental control of sex
c) Hormonal control of sex
d) Sex determination by chromosomes

97) The diagram representing the relative features and number of chromosomes is
a) Idiotype
b) Idiogram
c) Karyogram
d) Karyotype

98) Extra 18th autosomal chromosome results in
d) None of the above.

99) Hypertrichosis (hairy pinnae) is a trait linked to the
a) X-chromosome
b) Y-chromosome
c) Autosomes
d) None of the above

100) Lampbrush chromosomes possess in their loops
a) DNA
b) DNA+Proteins
d) DNA+RNA+Proteins


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