Heredity and Variation Class 12. We covered all the Heredity and Variation Class 12 in this post for free so that you can practice well for the exam.
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MCQ on Heredity and Variation Class 12 for NEET Students
Sickle cell anemia is
(A) an autosomal recessive disorder
(B) a sex-linked recessive disorder
(C) a disorder caused due aneuploidy
(D) an autosomal dominant disorder
Option a – an autosomal recessive disorder
Read the given statements and select the correct option. Statement I: The law of independent assortment states that when two pairs of traits are combined in a hybrid, the segregation of one pair of characters is independent of the other pair of characters. Statement II: The law of segregation is based on the fact that alleles do not show blending and both the characters are recovered in the F2 generation though one of these is not seen in F₁ stage.
(A) Statement I is correct, and statement II is incorrect.
(B) Statement I is incorrect, and statement II is correct.
(C) Both statements I and II are correct.
(D) Both statements I and II are incorrect.
Option c – Both statements I and II are correct.
Identify the INCORRECT statement.
(A) The queen bee and the worker bees develop from fertilized eggs.
(B) Male honey bees are haploid and female honey bees are diploid.
(C) Male honey bees produce sperm by meiosis.
(D) Drones are male honey bees whereas worker bees are female honey bees.
Option c – Male honey bees produce sperm by meiosis.
A woman with blood group ‘O’ has a child with blood group ‘O’. What will be the blood group of the father?
(A) A
(B) B
(C) O
(D) Any of these
Option d – Any of these
Which of the following is INCORRECT regarding Klinefelter’s syndrome?
(A) It is a genetic abnormality resulting in feminized males.
(B) It is caused due to the absence of one of the X chromosomes.
(C) The individual with this syndrome shows gynecomastia.
(D) The individuals with this syndrome are sterile.
Option b – It is caused due to the absence of one of the X chromosomes.
If a cross is made between Aa and aa, the nature of F₁ progeny will be
(A) 50% will have a dominant phenotype and 50% will have a recessive phenotype.
(B) All will have a dominant phenotype.
(C) All will have the recessive phenotype.
(D) 75% will have a dominant phenotype and 25% will have a recessive phenotype.
Option a – 50% will have a dominant phenotype and 50% will have a recessive phenotype.
Which of the following is an example of pleiotropy?
(A) Thalassemia
(B) Phenylketonuria
(C) Haemophilia
(D) All of these
Option b – Phenylketonuria
Identify the ODD one with respect to Mendelian disorders.
(A) Thalassemia
(B) Haemophilia
(C) Colour blindness
(D) Cushing’s disease
Option d – Cushing’s disease
When red-flowered pea plants are crossed with white-flowered pea plants, the F, hybrids had a genotype that did not resemble either of the two parents. When the F, hybrids were self-pollinated, the F₂ hybrids resulted in the genotypic ratio
(A) 3 : 1
(B) 1 : 2 : 1
(C) 9 : 3 : 3 : 1
(D) 3 : 1 : 2
Option b – 1 : 2 : 1
………. is NOT an example of intragenic interaction.
(A) Incomplete dominance
(B) Co-dominance
(C) Pleiotropy
(D) Multiple alleles
Option c – Pleiotropy
The pleiotropic gene is a gene that
(A) controls only one phenotype.
(B) can exhibit multiple phenotypic expressions.
(C) masks the expression of another non-allelic gene.
(D) obstructs crossing over.
Option b – can exhibit multiple phenotypic expressions.
When two pea plants with a single trait under consideration undergo crossing, then what would be the percentage of a recessive trait in F₂ generation?
(A) 25%
(B) 50%
(C) 75%
(D) 100%
Option a – 25%
……. is an example of monosomy.
(A) Turner’s syndrome
(B) Down’s syndrome
(C) Klinefelter’s syndrome
(D) None of these
Option a – Turner’s syndrome
Identify the dominant character studied by Mendel in the garden pea plant.
(A) The white color of the flower
(B) Constricted pod shape
(C) Wrinkled seed shape
(D) Inflated pod shape
Option d – Inflated pod shape
In Antirrhinum sp., the hybrid formed by crossing red (RR) and white (rr) flowering plants produce pink (Rr) flower. This is an example of
(A) Co-dominance
(B) Incomplete dominance
(C) Complete dominance
(D) Pleiotropy
Option b – Incomplete dominance
In which of the following males are homogametic?
(A) Birds
(B) Human
(C) Grasshopper
(D) Drosophila
Option a – Birds
Pick out the correct statements. i. Haemophilia is an X-linked recessive trait. ii. Down’s syndrome to results due monosomy of X. iii. Phenylketonuria recessive is an autosomal gene disorder. iv. Thalassemia has transmitted as a blood disease from parents to both offspring when partners are carriers of the disease.
(A) i and ii
(B) ii and iv
(C) i, ii and iii
(D) i, iii and iv
Option d – i, iii and iv
On crossing a tall and red flowered homozygous individual with a dwarf and white flowered homozygous individual, the progeny were found to be tall and red. What will be the genotype of the progeny?
(A) TtRr
(B) TTRR
(C) TTRr
(D) ttrr
Option a – TtRr
………. type of sex determination occurs in birds.
(A) ZZ-ZW
(B) XX-XY
(C) Haplodiploid
(D) XO
Option a – ZZ-ZW
Which of the following is INCORRECT regarding the back cross?
(A) In the recessive back cross, F, the individual is crossed with a recessive parent.
(B) In a dominant back cross, F₁ hybrids when crossed with the dominant parent, all progeny show dominant character.
(C) A back cross is always the dominant back cross.
(D) A back cross is not necessarily a test cross.
Option a – A back cross is always the dominant back cross
The number of gametes produced by an individual with genotype AABbCc is
(A) 4
(B) 2
(C) 9
(D) 8
Option a – 4
We covered all the heredity and variation class 12 above in this post for free so that you can practice well for the exam.
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