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

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 the options
Answer: b

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

Question: The template strand sequence of DNA of sickle cell anemia having valine (amino acid code GUG) is
a) CTC
b) GAG
c) GUG
d) None of the options
Answer: d

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 a person’s blood clotting ability is hampered
d) All are true
Answer: d

Question: Female birds contain
a) ZZ chromosomes
b) XX chromosomes
c) XO chromosomes
d) None of the options
Answer: d

Question: When insects having X chromosome in male sperm fertilize the egg, it produces
a) Male with X chromosomes
b) Female with XX chromosomes
c) Female with one less chromosome
d) None of the options
Answer: b

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 the options
Answer: b

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: 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
c) 75% round and 25% wrinkled
d) 50% round and 50% wrinkled
Answer: a

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

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: 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: 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: 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: 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: 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 the options
Answer: b

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

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

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

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

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: 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: 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: 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: 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: 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: 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: Family pedigree of Queen Victoria shows inheritance of which disease
a) Haemophilia
b) Sickle cell anemia
c) Phenylketonuria
d) Thalassemia
Answer: a

Question: Example of point mutation is
a) Malaria
b) Sickle cell anemia
c) Thyroid
d) None of the options
Answer: b

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, e.g. Down syndrome
Answer: c

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

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

Question: Phenylketonuria
a) Inborn error of metabolism
b) It is an autosomal recessive genetic disorder
c) Affected individual converts phenylalanine to phenylpyruvic acid and other derivatives causing mental retardation
d) All of the options
Answer: d

Question: Failure of cytokinesis results in
a) Aneuploidy
b) Aploidy
c) Polyploidy
d) None of the options
Answer: c

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

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

Question: Hb^s peptide for sickle cell anemia has alteration at which amino acid of the beta globin chain
a) 4
b) 7
c) 6
d) None of the options
Answer: c

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