CBSE Class 12 Biology Principles of Inheritance and Variation MCQs Set 03

Question: In birds with female heterogamety what determines the male sex of the offspring
(a) Chromosome present in sperm which fertilizes the egg
(b) Chromosome present in egg which fertilizes the sperm
(c) Temperature of body at the time of fertilization
(d) All of these

Answer : B

Question: Which of the following is responsible for alteration in DNA sequences?
(a) Monohybrid cross
(b) Replication
(c) Mutation
(d) None of these

Answer : C

Question: Among the following characters, which one was not considered by Mendel in his experiments on pea?
(a) Trichomes-Glandular or non-glandular
(b) Seed-Green or yellow
(c) Pod-Inflated or constricted
(d) Stem-Tall or dwarf

Answer : A

Question: Of a normal couple, half the sons are haemophiliac while half the daughters are carriers. The gene is located on
(a) X-chromosome of father
(b) Y-chromosome of father
(c) one X-chromosome of mother
(d) both the X-chromosomes of mother.

Answer : C

Question: HbA and HbS alleles of normal and sickle cell haemoglobin are
(a) Co-dominant alleles
(b) Multiple alleles
(c) Dominant-recessive alleles
(d) Cumulative alleles

Answer : C

Question: In birds, females are
(a) XX
(b) ZZ
(c) ZO
(d) ZW

Answer : D

Question: An abnormal human male phenotype involving an extra X-chromosome (XXY) is a case of
(a) Edward’s syndrome
(b) Klinefelter’s syndrome
(c) intersex
(d) Down’s syndrome.

Answer : B

Question: Test cross involves
(a) crossing between two genotypes with dominant trait
(b) crossing between two genotypes with recessive trait
(c) crossing between two F1 hybrids
(d) crossing the F1 hybrid with a double recessive genotype

Answer : D

Question: Two non-allelic genes produces the new phenotype when present together but fail to do so independently then it is called
(a) epistasis
(b) polygene
(c) non complementary gene
(d) complementary gene.

Answer : A

Question: A fruit fly is heterozygous for sex-linked genes, when mated with normal female fruit fly, the males specific chromosome will enter egg cell in the proportion
(a) 3 : 1
(b) 7 : 1
(c) 1 : 1
(d) 2 : 1.

Answer : C

Question: A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters affected. Which of the following mode of inheritance do you suggest for this disease?
(a) Sex-linked dominant
(b) Sex-linked recessive
(c) Sex-limited recessive
(d) Autosomal dominant

Answer : B

Question: A diseased man marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is
(a) sex linked dominant
(b) sex linked recessive
(c) sex limited character
(d) autosomal dominant.

Answer : A

Question: Family pedigree of queen Victoria shows inheritance of which disease
(a) Haemophilia
(b) Sickle cell anemia
(c) Phenylketoneuria
(d) Thalesemia

Answer : A

Question: Hb^s peptide for sickle cell anaemia have alteration at which amino acid of the beta globin chain
(a) 4
(b) 7
(c) 6
(d) None of these

Answer : C

Question: X – linked recessive gene is
(a) Always expressed in male
(b) Always expressed in female
(c) Never expressed in males
(d) Always expressed in males and female

Answer : A

Question: Which one is an example for chromosomal mutation
(a) Sickle cell anemia
(b) Muscular dystrophy
(c) Phenylketoneuria
(d) Klinefelter’s syndrome

Answer : D

Question: In a genetic cross having recessive epistasis, F2 phenotypic ratio would be
(a) 9 : 6 : 1
(b) 15 : 1
(c) 9 : 3 : 4
(d) 12 : 3 : 1.

Answer : C

Question: In hybridisation, Tt × tt gives rise to the progeny of ratio
(a) 2 : 1
(b) 1 : 2 : 1
(c) 1 : 1
(d) 1 : 2.  

Answer : C

Question: When a single gene influences more than one trait it is called
(a) pseudodominance
(b) pleiotropy
(c) epistasis
(d) none of these.

Answer : B

Question: Select the incorrect statement from the following.
(a) Galactosemia is an inborn error of metabolism.
(b) Small population size results in random genetic drift in a population.
(c) Baldness is a sex-limited trait.
(d) Linkage is an exception to the principle of independent assortment in heredity.

Answer : C

Question: Trisomy is
(a) Additional copy of one chromosome is present in a pair
(b) It ‘s a type of chromosomal disorder
(c) It is due to failure of cytokinesis
(d) The chromatids are not able to segregate during cell division and result in trisomy, ex. Down syndrome

Answer : C

Question: Independent assortment of genes does not take place when
(a) genes are located on homologous chromosomes
(b) genes are linked and located on same chromosome
(c) genes are located on non-homogenous chromosome
(d) all of these.

Answer : B

Question: In Snapdragon two plants with pink flowers were hybridized. The F1 plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR and white by rr genes.
(a) Rr
(b) rr
(c) rrr
(d) RR

Answer : A

Question: Which of the following condition is called monosomics
(a) 2n+1
(b) 2n+2
(c) 2n-1
(d) n+1

Answer : C

Question: In human beings 45 chromosomes/single X/XO abnormality causes
(a) Down’s syndrome
(b) Kinefelter’s syndrome
(c) Turner’s syndrome
(d) Edward’s syndrome.

Answer : C

Question: tt mates with Tt. What will be characteristic of offspring?
(a) 75% recessive
(b) 50% recessive
(c) 25% recessive
(d) All dominant

Answer : B

Question: Phenylketonuria
(a) Inborn error of metabolism
(b) It is an autosomal recessive genetic disorder
(c) Affected individual converts phenyl alanine to phenylpyruvic acid and other derivatives and causes mental retardation
(d) All of these

Answer : D

Question: During cell division, failure of segregation of chromatids results in
(a) Aneuploidy
(b) Aploidy
(c) Haploidy
(d) None of these

Answer : A

Question: F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1. It represents a case of
(a) co-dominance
(b) dihybrid cross
(c) monohybrid cross with complete dominance
(d) monohybrid cross with incomplete dominance.

Answer : D

Question: The genotype of a plant showing the dominant phenotype can be determined by
(a) test cross
(b) dihybrid cross
(c) pedigree analysis
(d) back cross.

Answer : A

Question: Which statement is true for X linked recessive trait?
(a) Shows inheritance from carrier female to male progeny
(b) Haemophilia is an example of this type of inheritance
(c) Haemophilia is a disorder in which person’s blood clotting ability is hampered
(d) All are true

Answer : D

Question: Failure of cytokinesis results in
(a) Aneuploldy
(b) Aploidy
(c) Polyploidy
(d) None of these

Answer : C

Question: In Antirrhinum two plants with pink flowers were hybridized. The F1 plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridisation? Red flower colour is determined by RR and white by rr genes.
(a) rrrr
(b) RR
(c) Rr
(d) rr

Answer : C

Question: When two unrelated individuals or lines are crossed, the performance of F1 hybrid is often superior to both its parents. This phenomenon is called
(a) heterosis
(b) transformation
(c) splicing
(d) metamorphosis.

Answer : A

Question: Which contribute to the success of Mendel?
(a) Qualitative analysis of data
(b) Observation of distinct inherited traits
(c) His knowledge of biology
(d) Consideration of one character at one time

Answer : D

Question: The genotypes of a husband and wife are IAIB and IAi. Among the blood types of their children, how many different genotypes and phenotypes are possible?
(a) 3 genotypes; 4 phenotypes
(b) 4 genotypes; 3 phenotypes
(c) 4 genotypes; 4 phenotypes
(d) 3 genotypes; 3 phenotypes

Answer : B

Question: Child has blood group “O” and his father is “B” type. Then genotype of the father should be
a) IBIB
b) IBIO
c) IAIB
d) IOIO

Answer : B

Question: Mendel’s last law is
(a) segregation
(b) dominance
(c) independent assortment
(d) polygenic inheritance.

Answer : C