Bihar Board 12th Biology Objective Questions and Answers
Bihar Board 12th Biology Objective Answers Chapter 5 Principles of Inheritance and Variation
Question 1.
The colour based contrasting traits in seven contrasting pairs, studied by Mendel in pea plant were
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(c) 3
Question 2.
_________ pairs of contrasting traits were studied by Mendel in pea plant.
(a) 6
(b) 7
(c) 8
(d) 10
Answer:
(b) 7
Question 3.
Which of the following characters was not chosen by Mendel ?
(a) Pod shape
(b) Pod colour
(c) Location of flower
(d) Location of pod
Answer:
(d) Location of pod
Question 4.
Genes which code for a pair of contrasting traits are known as
(a) dominant genes
(b) alleles
(c) linked genes
(d) none of these
Answer:
(b) alleles
Question 5.
A recessive allele is expressed in
(a) heterozygous condition only
(b) homozygous condition only
(c) F3 generation
(d) both homozygous and heterozygous conditions.
Answer:
(b) homozygous condition only
Question 6.
The characters which appear in the first filial generation are called
(a) recessive characters
(b) dominant characters
(c) holandric characters
(d) lethal characters
Answer:
(b) dominant characters
Question 7.
What will be the distribution of phenotypic features in the first filial generation after a cross between a homozygous female and a heterozygous male for a single locus ?
(a) 3 : 1
(b) 1 : 2 : 1
(c) 1 : 1
(d) None of these
Answer:
(c) 1 : 1
Question 8.
In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in F1 generation will be
(a) 25 %
(b) 50 %
(c) 75 %
(d) 100 %
Answer:
(b) 50 %
Question 9.
What is the probability of production of dwarf offsprings in a cross betweeen two heterozygous tall pea plants ?
(a) Zero
(b) 50 %
(c) 25 %
(d) 100 %
Answer:
(c) 25 %
Question 10.
Which of the following crosses will give tall and dwarf pea plants in same proportions ?
(a) TT × tt
(b) Tt × tt
(c) TT × Tt
(d) tt × tt
Answer:
(b) Tt × tt
Question 11.
To determine the genotype of a tall plant of F2 generation, Mendel crossed this plant with a dwarf plant. This cross represents a
(a) test cross
(b) back cross
(c) reciprocal cross
(d) dihybrid cross.
Answer:
(a) test cross
Question 12.
Which of the following is a test cross ?
(a) TT × TT
(b) Tt × Tt
(c) tt × tt
(d) Tt × tt
Answer:
(d) Tt × tt
Question 13.
Mendal formulated the law of purity of gametes on the basis of
(a) monohybrid cross
(b) dihybrid cross
(c) test cross
(d) back cross.
Answer:
(a) monohybrid cross
Question 14.
The inheritance of flower colour in Antirrhinum (dog flower) is an example of
(a) incomplete dominance
(b) co-dominance
(c) multiple alleles
(d) linkage.
Answer:
(a) incomplete dominance
Question 15.
In Antirrhinum (dog flower), phenotypic ratio in F2 generation for the inheritance of flower colour would be
(a) 3 : 1
(b) 1 : 2 : 1
(c) 1 : 1
(d) 2 : 1
Answer:
(b) 1 : 2 : 1
Question 16.
Phenotypic and genotypic ratio is similar in case of
(a) complete dominance
(b) incomplete dominance
(c) over dominance
(d) epistasis.
Answer:
(b) incomplete dominancec
Question 17.
What can be the blood group of offspring when both parents have AB blood group ?
(a) AB only
(b) A, B and AB
(c) A, B, AB and O
(d) A and B only
Answer:
(b) A, B and AB
Question 18.
Inheritance of roan coat in cattle is an example of
(a) incomplete dominance
(b) codominance
(c) multiple allelism
(d) none of these
Answer:
(b) codominance
Question 19.
ABO blood grouping in human beings cites the example of
(a) incomplete dominance
(b) co-dominance
(c) multiple allelism
(d) both
(b) and (c)
Answer:
(b) and (c)
Question 20.
In mice, Y is the dominant allele for yellow fur an y is the recessive allele for grey fur. Since Y is lethal when homozygous, the result of cross Yy × Yy will be
(a) 3 yellow : 1 grey
(b) 2 yellow : 1 grey
(c) 1 yellow : 1 grey
(d) 1 yellow : 2 grey
Answer:
(b) 2 yellow : 1 grey
Question 21.
In Mendelian dihybrid cross, when heterozygous Round Yellow are self crossed, Round Green offsprings are represented by the genotype
(a) RrYy, RrYY, RRYy
(b) Rryy, RRyy, rryy
(c) rrYy, rrYY
(d) Rryy, RRyy
Answer:
(d) Rryy, RRyy
Question 22.
The percentage of ab gamete produced by AaBb parent will be
(a) 25 %
(b) 50 %
(c) 75 %
(d) 12.5 %
Answer:
(a) 25 %
Question 23.
How many types of gametes can be produced by a diploid organism who is heterozygous for 4 loci ?
(a) 4
(b) 8
(c) 16
(d) 32
Answer:
(c) 16
Question 24.
Which of the following is correct for the condition when plant YyRr is back crossed with the double recessive parent ?
(a) 9 : 3 : 3 : 1 ratio of phenotypes only
(b) 9 : 3 : 3 : 1 ratio of genotypes only
(c) 1 : 1 : 1 : 1 ratio of phenotypes only
(d) 1 : 1 : 1 : 1 ratio of phenotypes and genotypes
Answer:
(d) 1 : 1 : 1 : 1 ratio of phenotypes and genotypes
Question 25.
Law of independent assortment can be explained with the help of
(a) dihybrid
(b) test cross
(c) back cross
(d) monohybrid cross
Answer:
(a) dihybrid
Question 26.
Mendel’s work was rediscovered by three scientists in the year
(a) 1865
(b) 1900
(c) 1910
(d) 1920
Answer:
(b) 1900
Question 27.
Which three scientists independently rediscovered Mendel’s work ?
(a) Avery, McLeod, McCarty
(b) Sutton, Morgan and Bridges
(c) Bateson, Punnet and Bridges
(d) de Vries, Correns and Tschemark
Answer:
(d) de Vries, Correns and Tschemark
Question 28.
Chromosomal theory of inheritance was given by
(a) Morgan et al
(b) Sutton and Boveri
(c) Hugo deVries
(d) Gregor J. Mendel
Answer:
(b) Sutton and Boveri
Question 29
Experimental verification of ‘chromosomal theory of inheritance’ was done by
(a) Sutton and Boveri
(b) Morgan et al
(c) Henking
(d) Karl Correns.
Answer:
(b) Morgan et al
Question 30.
Genes located very close to one another on same chromosome tend to be transmitted together and are called as
(a) allelomorphs
(b) identical genes
(c) linked genes
(d) recessive genes
Answer:
(c) linked genes
Question 31.
What is true about the crossing over between linked genes ?
(a) No crossing over at all
(b) High percentage of crossing over
(c) Hardly any crossing over
(d) None of these
Answer:
(c) Hardly any crossing over
Question 32.
Chromosome maps/genetic maps were first prepared by
(a) Sutton and Boveri (1902)
(b) Bateson and Punnett (1906)
(c) Morgan (1910)
(d) Sturtevant (1911)
Answer:
(d) Sturtevant (1911)
Question 33.
The distance between the genes is measured by
(a) angstrom
(b) map unit
(c) Dobson unit
(d) millimetre
Answer:
(c) Dobson unit
Question 34.
Which of the following is suitable for experiment on linkage ?
(a) aaBB x aaBB
(b) AABB x aabb
(c) AaBb x AaBb
(d) AAbb x AaBB
Answer:
(b) AABB x aabb
Question 35.
Mendel’s law of independent assortment does not hold true for the genes that are located closely on
(a) same chromosome
(b) non-homologous chromosomes
(c) X-chromosome
(d) autosomes
Answer:
(a) same chromosome
Question 36.
If linkage was known at the time of Mendel then which of the following laws, he would not have been able to explain ?
(a) Law of dominance
(b) Law of independent assortment
(c) Law of segregation
(d) Law of purity of gametes
Answer:
(b) Law of independent assortment
Question 37.
Which of the following are reasons for Mendel’s success ?
(i) Usage of pure lines or pure breeding varieties
(ii) Consideration of one character at a time
(iii) Maintenance of statistical records of experiments
(iv) Knowledge of linkage and incomplete dominance
(a) (i) and (ii) only
(b) (i), (ii) and (iii)
(c) (i) and (iv) only
(d) (ii), (iii) and (iv)
Answer:
(b) (i), (ii) and (iii)
Question 38.
XO type of sex determination and XY type of sex determination are the examples of
(a) male heterogamety
(b) female heterogamety
(c) male homogamety
(d) both (b) and (c)
Answer:
(a) male heterogamety
Question 39.
Grasshopper is an example of XO type of sex determination in which the males have
(a) one X chromosome
(b) one Y chromosome
(c) two X chromosomes
(d) no X chromosome
Answer:
(a) one X chromosome
Question 40.
In XO type of sex determination
(a) females produce two different types of gametes
(b) males produce two different types of gametes
(c) females produce gametes with Y chromosome
(d) males produce gametes with Y chromosome.
Answer:
(b) males produce two different types of gametes
Question 41.
Which of the following is incorrect regarding ZW – ZZ type of sex determination ?
(a) It occurs in birds and some reptiles.
(b) Females are homogametic and males are heterogametic.
(c) 1:1 sex ratio is produced in the offsprings.
(d) All of these
Answer:
(b) Females are homogametic and males are heterogametic.
Question 42.
A couple has six daughters. What is the possibility of their having a girl next time ?
(a) 10 %
(b) 50 %
(c) 90 %
(d) 100 %
Answer:
(b) 50 %
Question 43.
Number of autosomes present in liver cells of a human female is
(a) 22 autosomes
(b) 22 pairs
(c) 23 autosomes
(d) 23 pairs
Answer:
(b) 22 pairs
Question 44.
Haplodiploidy is found in
(a) grasshoppers and cockroaches
(b) birds and reptiles
(c) butterflies and moths
(d) honeybees, ants and waspe.
Answer:
(d) honeybees, ants and waspe.
Question 45.
Rate of mutation is affected by
(a) temperature
(b) X-rays
(c) gamma rays
(d) all of these.
Answer:
(d) all of these.
Question 46.
Two or more independent genes present on different chromosomes which determine nearly same phenotype are called
(a) supplementary genes
(b) complementary genes
(c) duplicate genes
(d) none of these.
Answer:
(c) duplicate genes
Question 47.
Select the incorrect statement regarding pedigree analysis.
(a) Solid symbols show unaffected individuals.
(b) Proband is the person from which case history starts.
(c) It is useful for genetic counsellors.
(d) It is an analysis of traits in several generations of a family.
Answer:
(a) Solid symbols show unaffected individuals.
Question 48.
Which one is the incorrect match ?
Answer:
Question 49.
________ is an example of X-linked recessive trait.
(a) Phenylketonuria
(b) Haemophilia
(c) Cystic fibrosis
(d) Sickle-cell anaemia
Answer:
(b) Haemophilia
Question 50.
Result of a cross between a normal homozygous female and a haemophiliac male would be
(a) normal males and normal females
(b) haemophilic males and normal females
(c) normal males and carrier females
(d) haemophilic males and carrier females.
Answer:
(c) normal males and carrier females
Question 51.
Father of a child is colourblind and mother is carrier for colourblindness, the probability of the child being colour blind is
(a) 25 %
(b) 50 %
(c) 100 %
(d) 75 %
Answer:
(b) 50 %
Question 52.
A marriage between a colourblind man and a normal woman produces
(a) all carrier daughters and normal sons
(b) 50% carrier daughters, 50% normal daughters
(c) 50% colourblind sons, 50% normal sons
(d) all carrier offsprings.
Answer:
(a) all carrier daughters and normal sons
Question 53.
Which of the following is not an example of recessive autosomal disease ?
(a) Haemophilia
(b) Cystic fibrosis
(c) Phenylketonuria
(d) Sickle-cell anaemia
Answer:
(a) Haemophilia
Question 54.
If both parents are carriers for thalassaemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child ?
(a) 25 %
(b) 100 %
(c) No chance
(d) 50 %
Answer:
(a) 25 %
Question 55.
Select the disease which is caused by recessive autosomal genes when present in homozygous conditions.
(a) Alkaptonuria
(b) Albinism
(c) Cystic fibrosis
(d) All of these
Answer:
(d) All of these
Question 56.
Which of the following trait is controlled by dominant autosomal genes ?
(a) Polydactyly
(b) Huntington’s chorea
(c) PTC (phenylthiocarbamide) tasting
(d) All of these
Answer:
(d) All of these
Question 57.
Failure of segregation of chromatids during cell division results in the gain or loss of chromosomes, this is called as
(a) euploidy
(b) monoploidy
(c) aneuploidy
(d) polyploidy
Answer:
(c) aneuploidy
Question 58.
Trisomy is represented by
(a) (2n – 1)
(b) (2n – 2)
(c) (2n + 2)
(d) (2n + 1)
Answer:
(d) (2n + 1)
Question 59.
Mongolism is a genetic disorder which is caused by the presence of an extra chromosome number
(a) 20
(b) 21
(c) 17
(d) 23
Answer:
(b) 21
Question 60.
Klinefelter’s syndrome is characterised by a karyotype of
(a) XYY
(b) XO
(c) XXX
(d) XXY
Answer:
(d) XXY
Question 61.
This abnormality occurs due to monosomy (2n – 1); the individual has 2n = 45 chromosomes with 44 + XO genotype.
(a) Edward’s syndrome
(b) Down’s syndrome
(c) Turner’s syndrome
(d) Klinefelter’s syndrome
Answer:
(c) Turner’s syndrome
Question 62.
Females with Turner’s syndrome have
(a) small uterus
(b) rudimentary ovaries
(c) underdeveloped breasts
(d) all of these.
Answer:
(d) all of these.
Question 63.
All genes located on the same chromosome
(a) form different groups depending upon their relative distance
(b) form one linkage group
(c) will not from any linkage groups
(d) form interactive groups that affect the phenotype.
Answer:
(b) form one linkage group
Question 64.
Conditions of a karyotype 2n±l and 2n + 2 are called
(a) aneuploidy
(b) polyploidy
(c) allopolyploidy
(d) monosomy.
Answer:
(a) aneuploidy
Question 65.
Distance between the genes and percentage of recontbfnatidnshows
(a) a direct relationship
(b) an inverse relationship
(c) a parallel relationship
(d) no relationship.
Answer:
(a) a direct relationship
Question 66.
If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is
(a) autosomal dominant
(b) autosomal recessive
(c) sex-linked dominant
(d) sex-linked recessive.
Answer:
(d) sex-linked recessive.
Question 67.
In sickle cell anaemia glutamic acid is replaced by valine. Which one of the following triplets codes for valine?
(a) GGG
(b) A AG
(c) G A A
(d) GUG
Answer:
(d) GUG
Question 68.
Person having genotype IA IB would show the blood group as AB. This is because of
(a) pleiotropy
(b) co-dominance
(c) segregation
(d) incomplete dominance.
Answer:
(b) co-dominance
Question 69.
ZZ/ZW type of sex determination is seen in
(a) platypus
(b) snails
(c) cockroach
(d) peacock
Answer:
(d) peacock
Question 70.
A cross between two tall plants resulted in offspring having few dwarf plants. What would be the genotypes of both the parents?
(a) TT and Tt
(b) Tt and Tt
(c) TT and TT
(d) Tt and It
Answer:
(b) TtandTt
Question 71.
In a dihybrid cross, if you get 9 : 3 : 3 : 1 ratio it denotes that
(a) the alleles of two genes are interacting with each other
(b) it is a multigenic inheritance
(c) it is a case of multiple allelism
(d) the alleles of two genes are segregating independently.
Answer:
(d) the alleles of two genes are segregating independently.
Question 72.
Which of the following will not result in variations among siblings?
(a) Independent assortment of genes
(b) Crossing over
(c) Linkage
(d) Mutation
Answer:
(c) Linkage
Question 73.
Mendel’s Law of independent assortment holds good for genes situated on the
(a) non-homologous chromosomes
(b) homologous chromosomes
(c) extranuclear genetic element
(d) same chromosome.
Answer:
(b) homologous chromosomes
Question 74.
Occasionally, a single gene may express more than one effect. The phenomenon is called
(a) multiple allelism
(b) mosaicism
(c) pleiotropy
(d) polygeny.
Answer:
(c) pleiotropy
Question 75.
In the F2 generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are
(a) phenotypes – 4; genotypes – 16
(b) phenotypes – 9; genotypes – 4
(c) phenotypes – 4; genotypes – 8
(d) phenotypes – 4; genotypes – 9.
Answer:
(d) phenotypes – 4; genotypes – 9.