NEET Botany Principles of Inheritance and Variation Class 12 Questions

A women having blood group O married with a man having blood group AB. Which blood group may be expected in their progenies?

Which is the dominant trait

In case of codominance:

Which one of the following conditions correctly describes the manner of determining the sex in the given example?

What phenomenon results in alteration of DNA sequences and changes in genotype and phenotype of an organism?

What is the number of alleles involved in ABO blood grouping?

In a cross between true-breeding red-flowered and true-breeding white-flowered snapdragons, what phenotype is observed in the F1 generation?

What is the process by which characters are passed on from parent to offspring?

What is the main characteristic of BB homozygotes in terms of starch synthesis in pea seeds?

What is the phenotype ratio observed in the F2 generation when true-breeding red-flowered and true-breeding white-flowered snapdragons are crossed?

What is the phenotypic ratio observed in a dihybrid cross according to Mendel's Law of Independent Assortment?

What is the genetic basis of α Thalassemia?

What genetic disorder is characterized by the presence of an additional copy of chromosome number 21?

What phenotype ratio is observed in the F2 generation of the snapdragon flower color inheritance cross?

What is the phenotypic ratio in the F2 generation when red-flowered (RR) and white-flowered (rr) snapdragons are crossed?

What is the phenotype ratio observed in the F2 generation of snapdragons when true-breeding red and white flowered plants are crossed?

What is the genetic cause of Down's syndrome?

What was the observation made by Mendel regarding the F1 progeny of a cross between tall and dwarf pea plants?

What type of inheritance is illustrated by the flower color of snapdragons where the F1 generation exhibits a pink phenotype?

Which of the following statements about genetic variation is correct?

Which of the following statements about Mendel's work and inheritance is correct?

Which of the following statements about Mendel's principles of inheritance is correct?

Which of the following statements about Mendelian disorders is correct?

Which of the following statements about Mendel's experiments on pea plants is correct?

Which of the following statements about sex determination and mutations is correct?

Which of the following statements about Mendel's laws and genetic principles is correct?

Which of the following statements about genetic inheritance is correct?

Which of the following statements about genetic mutations and their effects is correct?

Which of the following statements about genetic disorders and inheritance is correct?

Which of the following statements about Mendel's work and the principles of inheritance is correct?

Assertion (A): Mutation can lead to chromosomal aberrations.

Reason (R): Mutations only involve changes in single base pairs of DNA.

Assertion (A): Down's syndrome is caused by an additional copy of chromosome 21.

Reason (R): Trisomy of a chromosome always results in a beneficial trait for the individual.

Assertion (A): In the dihybrid cross, the phenotypic ratio observed is 9:3:3:1.

Reason (R): The Law of Independent Assortment states that when two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair.

Assertion (A): Human skin color is an example of polygenic inheritance.

Reason (R): Polygenic traits are controlled by a single pair of alleles.

Assertion (A): In the F2 generation of a monohybrid cross, the phenotypic ratio of tall to dwarf plants is 3:1.

Reason (R): The segregation of alleles during gamete formation is a random process, leading to a 50% chance of a gamete containing either allele.

Assertion (A): In the XO type of sex determination, eggs fertilised by sperm without an X-chromosome become males.

Reason (R): In the XO system, all eggs bear an additional X-chromosome besides the other chromosomes.

Assertion (A): The substitution of valine for glutamic acid in the beta globin chain of haemoglobin leads to sickle cell anemia.

Reason (R): This substitution results from a single base change in the beta globin gene, causing polymerisation of haemoglobin under low oxygen tension.

Assertion (A): Mutations can lead to chromosomal aberrations.

Reason (R): Mutations only occur through the recombination of DNA sequences.

Assertion (A): Thalassemia is a blood disease resulting from a defect in haemoglobin synthesis.

Reason (R): In α Thalassemia, the production of β globin chain is affected due to mutations or deletions.

Assertion (A): Incomplete dominance results in a phenotype ratio of 1:2:1 in the F2 generation.

Reason (R): Incomplete dominance occurs because one allele is not completely dominant over the other, resulting in an intermediate phenotype.

Assertion (A): Genes determine the phenotype of an organism.

Reason (R): Alleles are slightly different forms of the same gene that do not affect the expression of traits.

Assertion (A): Polygenic traits are controlled by a single gene with multiple alleles.

Reason (R): Human skin colour is an example of a polygenic trait influenced by multiple genes and environmental factors.

Assertion (A): Down's syndrome is caused by the presence of an additional copy of chromosome 21.

Reason (R): Down's syndrome is an example of a chromosomal disorder resulting from trisomy.

Match Column-I with Column-II.

Match Column-I with Column-II.

Match Column-I with Column-II.

Match Column-I with Column-II.

In a monohybrid cross involving height in pea plants, what is the probability that a gamete from a heterozygous Tt plant carries the dominant allele T?

In Mendel's experiments, if T represents the dominant allele for tallness and t represents the recessive allele for dwarfness, what is the probability of obtaining a dwarf plant in the F2 generation from a monohybrid cross?

In a genetic cross between two heterozygous tall pea plants (Tt), what is the probability of obtaining a homozygous recessive dwarf plant (tt) in the F2 generation?