Principles of Inheritance and Variation Chapter-Wise Test 10

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What is the expected genotypic ratio of a monohybrid cross in the F2 generation?

3:1
9:3:3:1
1:2:1
2:1
3

The genotypic ratio of a monohybrid cross (F2 generation) is 1:2:1 (homozygous dominant: heterozygous: homozygous recessive).

Which genetic concept explains why males are more likely to express X-linked recessive traits?

Dosage compensation
Hemizygosity
Polygenic inheritance
Epistasis
2

Hemizygosity explains why males (XY) express X-linked recessive traits more frequently, as they have only one X chromosome.

What is the role of crossing over during meiosis?

Prevents genetic variation
Increases genetic diversity
Ensures mitosis occurs properly
Maintains identical copies of genes
2

Crossing over during meiosis increases genetic diversity by exchanging genetic material between homologous chromosomes.

What is the primary genetic cause of hemophilia?

Trisomy of chromosome 21
A mutation in the X chromosome
Deletion of chromosome 5
A mutation in the Y chromosome
2

Hemophilia is a sex-linked recessive disorder caused by a mutation in the X chromosome.

In Mendelian inheritance, what is the expected genotypic ratio of the F2 generation in a monohybrid cross?

3:1
9:3:3:1
1:2:1
2:1
3

The expected genotypic ratio in a monohybrid cross (F2 generation) is 1:2:1 (homozygous dominant: heterozygous: homozygous recessive).

Which scientist discovered the concept of sex-linked inheritance through experiments on fruit flies?

Gregor Mendel
Thomas Hunt Morgan
Sutton and Boveri
Watson and Crick
2

Thomas Hunt Morgan discovered sex-linked inheritance by studying eye color inheritance in Drosophila melanogaster.

Which of the following is a correct statement about pleiotropy?

A single gene affects multiple traits.
Multiple genes control a single phenotype.
Pleiotropy follows Mendel’s Law of Independent Assortment.
It occurs only in plants.
1

Pleiotropy occurs when a single gene influences multiple phenotypic traits, such as in sickle-cell anemia.

Which of the following statements about dominant and recessive traits is incorrect?

A dominant allele expresses its trait in both homozygous and heterozygous conditions.
A recessive allele expresses its trait only in the homozygous condition.
Dominant traits are always more common in a population than recessive traits.
Recessive traits can be passed on through generations without being expressed.
3

Dominant traits are not necessarily more common; frequency depends on factors like natural selection and genetic drift.

Which of the following correctly describes polygenic inheritance?

One gene controls multiple traits.
Multiple genes influence a single trait.
A single gene determines a single phenotype.
Traits are inherited only from one parent.
2

Polygenic inheritance occurs when multiple genes contribute to a single phenotype, such as human height.

Which scientist proposed the Chromosomal Theory of Inheritance?

Gregor Mendel
Thomas Hunt Morgan
Sutton and Boveri
Watson and Crick
3

Sutton and Boveri proposed the Chromosomal Theory of Inheritance, linking Mendel’s principles to chromosome behavior.

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