Biology MCQ
#3 Biology Class 12 Chapter 3- Inheritance and Variation MHTCET / NEET MCQ
3 - Inheritance and Variation
MHTCET - MCQ
(1) Phenotypic ratio of incomplete dominance in Mirabilis jalapa.
(a) 2 : 1 : 1(b) 1 : 2 : 1(c) 3 : 1(d) 2 : 2
Ans- 1 : 2 : 1
(2) In dihybrid cross, F2 generation offspring show four different phenotypes while the genotypes are .......... .
(a) six(b) nine(c) eight(d) sixteen
Ans- nine
(3) A cross between an individual with unknown genotype for a trait with recessive plant for that trait is .......... .
(a) back cross(b) reciprocal cross(c) monohybrid cross(d) test cross
Ans- test cross
(4) When phenotypic and genotypic ratios are the same, then it is an example of .......... .
(a) incomplete dominance(b) complete dominance(c) multiple alleles(d) cytoplasmic inheritance
Ans- incomplete dominance
(5) If the centromere is situated near the end of the chromosome, the chromosome is called .......... .
(a) Metacentric(b) Acrocentric(c) Sub-Metacentric(d) Telocentric
Ans- Telocentric
(6) Chromosomal theory of inheritance was proposed by .......... .
(a) Sutton and Boveri(b) Watson and Crick(c) Miller and Urey(d) Oparin and Halden
Ans- Sutton and Boveri
(7) If the genes are located in a chromosome as p-q-r-s-t, which of the following gene pairs will have least probability of being inherited together ?
(a) p and q(b) r and s(c) s and t(d) p and s
Ans- p and s
(8) Find the mismatched pair :
(a) Down’s syndrome = 44 + XY(b) Turner’s syndrome = 44 + XO(c) Klinefelter’s syndrome = 44 + XXY(d) Super female = 44 + XXX
Ans- Down’s syndrome = 44 + XY
(9) A colourblind man marries a woman, who is homozygous for normal colour vision, the probability of their son being colour blind is –
(a) 0%(b) 25%(c) 50%(d) 100%
Ans- 0%
(10) Which one of the following characters is recessive in case of pea plant ?
(a) Axial flower(b) Green pod(c) Green seed(d) Inflated pod
Ans- Green seed
(11) Which of the following trait is dominant in Pisum sativum ?
(a) White flowers(b) Green seeds(c) Yellow pods(d) Inflated pods
Ans- Inflated pods
(12) When phenotypic and genotypic ratio is the same, then it is an example of .
(a) incomplete dominance(b) cytoplasmic inheritance(c) quantitative inheritance(d) incomplete dominance and co-dominance
Ans- incomplete dominance
(13) A pea plant with yellow and round seeds is crossed with another pea plant with green and wrinkled seeds produce 51 yellow round seeds and 49 yellow wrinkled seeds, the genotype of plant with yellow round seeds must be .
(a) YYRr(b) YyRr(c) YyRR(d) YYRR
Ans- YYRr
(14) When a single gene produces two effects and one of it is lethal, then the ratio is.
(a) 2 : 1(b) 1 : 1(c) 1 : 2 : 1(d) 1 : 1 : 1 : 1
Ans- 2 : 1
(15) When two genes control a single character and have cumulative effect, the ratio is.
(a) 1 : 1 : 1 : 1(b) 1 : 4 : 6 : 4 : 1(c) 1 : 2 : 1(d) 1 : 6 : 15 : 20 : 15 : 6 : 1
Ans- 1 : 6 : 15 : 20 : 15 : 6 : 1
(16) Genes located on the same locus but show more than two different phenotypes are called ……… .
(a) polygenes(b) multiple alleles(c) co-dominants(d) pleiotropic genes
Ans- multiple alleles
(17) Genotype refers to the genetic composition of ……… .
(a) an organism(b) an organ(c) chromosomes(d) germ cells
Ans- an organism
(18) Individuals having identical alleles of a gene are known as ……… .
(a) homozygous(b) heterozygous(c) hybrids(d) dominants
Ans- homozygous
(19) If a heterozygous tall plant is crossed with a homozygous dwarf plant, the proportion of dwarf progeny will be ……… .
(a) 100 per cent(b) 75 per cent(c) 50 per cent(d) 25 per cent
Ans- 50 per cent
(20) Inheritance of AB blood group is due to ……… .
(a) incomplete dominance(b) polyploidy(c) polygeny(d) co-dominance
Ans- co-dominance
(21) The recombination of characters in a dihybrid cross is related to ……… .
(a) law of dominance(b) incomplete dominance(c) co-dominance(d) independent assortment
Ans- independent assortment
(22) Which one of the following is a true pleiotropic gene ?
(a) HbA(b) Hbs(c) HbD(d) HbP
Ans- Hbs
(23) For demonstrating the law of independent assortment, one should carry out ……… .
(a) back cross(b) test cross(c) dihybrid cross(d) monohybrid cross
Ans- dihybrid cross
(24) Which one of the following is an example of multiple alleles ?
(a) Height in pea plant(b) Hair colour in cattle(c) Petal colour in four o’clock plant(d) Wing-size in Drosophila
Ans- Wing-size in Drosophila
(25) For the formation of 50 seeds, how many minimum meiotic divisions are necessary ?
(a) 25(b) 50(c) 75(d) 63
Ans- 63
(26) A cross used to verify the unknown genotype of F1 hybrid is a cross.
(a) test(b) back(c) dihybrid(d) monohybrid
Ans- test
(27) Appearance of new combinations in F2 generation in a dihybrid cross proves the law of .
(a) dominance(b) segregation(c) independent assortment(d) purity of gametes
Ans- independent assortment
(28) Genotype of human blood group ‘O’ will be .
(a) IAIA(b) IAIB(c) ii(d) IAi
Ans- ii
(29) The genotype of human blood group B is ………
(a) IAi(b) IBi(c) IAIB(d) ii
Ans- IBi
(30) ……… chromosome appears ‘V’-shaped during anaphase.
(a) Metacentric(b) Acrocentric(c) Telocentric(d) Sub-Metacentric
Ans- Metacentric
(31) The sister chromatids are held together by .......... .
(a) centrioles(b) chromonemata(c) chromomere(d) centromere
Ans- centromere
(32) Which of the following is not X-linked disorder ?
(a) Haemophilia(b) Night-blindness(c) Hypertrichosis(d) Myopia
Ans- Hypertrichosis
(33) Which of the following is also called bleeder’s disease ?
(a) Anaemia(b) Thrombocytopenia(c) Polycythemia(d) Haemophilia
Ans- Haemophilia
(34) The person with Turner’s syndrome has .......... .
(a) 45 autosomes and X sex chromosome(b) 44 autosomes and XYY sex chromosome(c) 45 autosomes and Y chromosome(d) 44 autosomes and X chromosome
Ans- 44 autosomes and X chromosome
(35) Which of the following is sex chromosomal disorder ?
(a) Colour blindness(b) Turner’s syndrome(c) Thalassemia(d) Down’s syndrome
Ans- Turner’s syndrome
(36) The word chroma means ……… .
(a) a part of nucleus(b) a part of chromosome(c) colour(d) filamentous body
Ans- colour
(37) Presence of whole sets of chromosomes is called .......... .
(a) aneuploidy(b) euploidy(c) ploidy(d) chromatography
Ans- euploidy
(38) The synonymous term for centromere is ……… .
(a) primary constriction(b) secondary constriction(c) telomere(d) satellite
Ans- primary constriction
(39) Small swellings on the surface of the chromosome are called ……… .
(a) centromeres(b) chromonemata(c) chromomeres(d) telomeres
Ans- centromeres
(40) On what basis are the chromosomes usually classified ?
(a) On the basis of their function(b) On the basis of their length(c) On the basis of the position of the centromere(d) On the basis of their number
Ans- On the basis of the position of the centromere
(41) Find the mismatched pair :
(a) Metacentric – V-shaped(b) Sub-Metacentric – L-shaped(c) Acrocentric – J-shaped(d) Telocentric – S-shaped
Ans- Telocentric – S-shaped
(42) Out of the following combinations which individual will have maximum genetically active DNA ?
(a) 44 + XX(b) 44 + XY(c) 44 + XYY(d) Down’s syndrome
Ans- 44 + XX
(43) Crossing over occurs at the time of
(a) diplotene(b) pachytene(c) leptotene(d) zygotene
Ans- pachytene
(44) A mature woman has ……… linkage groups.
(a) 44(b) 22(c) 46(d) 23
Ans- 23
(45) The pairing of homologous chromosomes is called ……… .
(a) crossing over(b) terminalisation(c) synapsis(d) bivalent
Ans- synapsis
(46) If only one ‘X’ chromosome is found in a female person, which of the following symptoms will she show ?
(a) epicanthal skin fold(b) webbing of neck(c) small testis and absence of spermatogenesis(d) presence of simian crease on the palm
Ans- webbing of neck
(47) If centromere is situated in the middle of the chromosome, it is called ……… .
(a) metacentric(b) acrocentric(c) submetacentric(d) telocentric
Ans- metacentric
(48) In which of the following disorders the number of chromosomes present is (extra) 47 ?
(a) Turner’s syndrome(b) Cushing’s syndrome(c) Acquired immuno-deficiency syndrome(d) Down’s syndrome
Ans- Down’s syndrome
(49) Myopia is an example of ……… .
(a) complete sex linkage(b) incomplete sex linkage(c) recombination(d) crossing over
Ans- complete sex linkage
(50) Down’s syndrome is represented by ……….
(a) n + 1(b) 2n + 1(c) 3n + 1(d) n - 1
Ans- 2n + 1
