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

Question: In XO type sex determination male and female have
(a) Equal number of chromosomes
(b) Females have one more chromosome
(c) Males have one more chromosome
(d) Females have two extra chromosomes

Answer : B

Question: When insects having X chromosome in Male sperm fertilizes the egg it produces?
(a) Male with X chromosomes
(b) Female with XX chromosomes
(c) Female with one less chromosome
(d) None of these

Answer : B

Question: The Template strand sequence of DNA of sickle cell anaemia having valine (amino acid code GUG) in
(a) CTC
(b) GAG
(c) GUG
(d) None of these

Answer : D

Question: X linked recessive disorder
(a) Transfers character from male parent to male child
(b) Female carriers to male child
(c) Female carries to female child
(d) Both 2 and 3

Answer : D

Question: A holandric gene cause hypertrichosis.When a man with hypertrichosis marries a normal women, what percentage of their daughters would be expected to have hypertrichosis?
(a) 50%
(b) 25%
(c) 75%
(d) 0%

Answer : D

Question: A phenomenon of a single gene regulating several phenotypes is called
(a) Multiple allelism
(b) Pleiotropy
(c) Incomplete dominance
(d) Co-dominance

Answer : B

Question: Experimental verification of the chromosomal theory of inheritance was done by
(a) Mendel
(b) Sutton
(c) Boveri
(d) Morgan.

Answer : D

Question: Multiple alleles are present
(a) at the same locus of the chromosome
(b) on non-sister chromatids
(c) on different chromosomes
(d) at different loci on the same chromosome

Answer : A

Question: A human male produces sperms with the genotypes AB, Ab, aB and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?
(a) AaBB
(b) AABb
(c) AABB
(d) AaBb

Answer : D

Question: In a test cross involving F1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates
(a) the two genes are linked and present on the same chromosome
(b) both of the characters are controlled by more than one gene
(c) the two genes are located on two different chromosomes
(d) chromosomes failed to separate during meiosis.

Answer : A

Question: Thalassemia and sickle cell anaemia are caused due to a problem in globin molecule synthesis. Select the correct statement.
(a) Both are due to a quantitative defect in globin chain synthesis.
(b) Thalassemia is due to less synthesis of globin molecules.
(c) Sickle cell anaemia is due to a quantitative problem of globin molecules.
(d) Both are due to a qualitative defect in globin chain synthesis.

Answer : B

Question: A colour blind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colour blind ?
(a) Nil
(b) 0.25
(c) 0.5
(d) 1

Answer : B

Question: Homogametic sex chromosomes are present in females of
(a) Humans and birds
(b) Humans and D. melanogaster
(c) Birds and insects
(d) None of these

Answer : B

Question: Female birds contains
(a) ZZ chromosomes
(b) XX chromosomes
(c) XO chromosomes
(d) None of these

Answer : D

Question: Turner’s syndrome is due to
(a) Aneuploidy
(b) Monosomy
(c) 44 + XO
(d) All are true

Answer : D

Question: The genes controlling the seven pea characters studied by Mendel are now known to be located on how many different chromosomes?
(a) Seven
(b) Six
(c) Five
(d) Four

Answer : D

Question: Skin colour is controlled by
(a) Pleiotropic genes
(b) Dominant genes
(c) Polygenes
(d) Recessive gene

Answer : C

Question: Test cross is a cross between
(a) Hybrid x Dominant parent
(b) Hybrid x Recessive parent
(c) Hybrid x Hybrid
(d) Dominant parent x Recessive parent

Answer : B

Question: Male XX and female XY sometime occur due to
(a) deletion
(b) transfer of segments in X and Y chromosome
(c) aneuploidy
(d) hormonal imbalance.

Answer : B

Question: Which of the following is suitable for experiment on linkage?
(a) aaBB × aaBB
(b) AABB × aabb
(c) AaBb × AaBb
(d) AAbb × AaBB

Answer : B

Question: Female heterogamety is present in
(a) Drosophila melanogaster
(b) Homo sapiens
(c) Gallus gallus domesticus(chicken)
(d) None of these

Answer : C

Question: Example of point mutation is
(a) Malaria
(b) Sickle cell anemia
(c) Thyroid
(d) None of these

Answer : B

Question: Round seed is dominant over wrinkled seeds in Pea. If homozygous, round seeded Pea plants are crossed with wrinkled seeded plants, the offsprings will be
(a) All round
(b) All wrinkled
(b) 75% round and 25% wrinkled
(d) 50% round and 50% wrinkled

Answer : D

Question: Indicate, the inheritance of which of the following is controlled by multiple alleles
(a) Colour blindness
(b) Sickle cell anemia
(c) Blood group
(d) Phenylketoneuria

Answer : C

Question: A child’s blood group is ‘O’. The parent’s blood groups cannot be
(a) A and B
(b) A and A
(c) AB and O
(d) B and O.

Answer : C

Question: An organism with two identical alleles is
(a) dominant
(b) hybrid
(c) heterozygous
(d) homozygous.

Answer : D

Question: Which one is a hereditary disease?
(a) Cataract
(b) Leprosy
(c) Blindness
(d) Phenylketonuria

Answer : D

Question: Segregation of Mendelian factors (no linkage, no crossing over) occurs during
(a) anaphase I
(b) anaphase II
(c) diplotene
(d) metaphase I.

Answer : A

Question: In order to find out the different types of gametes produced by a pea plant having the genotype AaBb it should be crossed to a plant with the genotype
(a) AABB
(b) AaBb
(c) aabb
(d) aaBB.

Answer : C

Question: Down’s syndrome in humans is due to
(a) three ‘X’ chromosomes
(b) three copies of chromosome 21
(c) monosomy
(d) two ‘Y’ chromosomes

Answer : B

Question: A male human is heterozygous for autosomal genes A and B and is also hemizygous for haemophilic gene h. What proportion of his sperms will be abh?
(a) 1/8
(b) 1/32
(c) 1/16
(d) 1/4

Answer : A

Question: Segregation of genes occurs in
(a) Embryo formation
(b) Anaphase II
(c) Anaphase I
(d) Metaphase II

Answer : C

Question: The plant in which Hugo de Vries introduces the concept of mutation is
(a) Oenothera lamarkiana
(b) Pisum sativum
(c) Allium cepa
(d) Mirabilis jalapa

Answer : A

Question: A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in the ratio of
(a) 3 : 1 : : Tall : Dwarf
(b) 3 : 1 : : Dwarf : Tall
(c) 1 : 2 : 1 : : Tall homozygous : Tall heterozygous : Dwarf
(d) 1 : 2 : 1 : : Tall

Answer : C

Question: Which statement is true for pedigree analysis?
(a) This was made for studying the inheritance pattern of traits in human
(b) Control crosses were not possible in humans so inheritance pattern studied
(c) Analysis of inheritance of particular trait in several generations of family is called pedigree analysis
(d) All of these

Answer : D

Question: A normal green male maize is crossed with albino female. The progeny is albino because
(a) trait for a albinism is dominant
(b) the albinos have biochemical to destroy plastids derived from green male
(c) plastids are inherited from female parent
(d) green plastids of male must have mutated.

Answer : C