Principles of Inheritance and Variation
Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which type of cross did Mendel perform to study the inheritance of two different traits?

Monohybrid cross
Test cross
Dihybrid cross
Back cross
3

A dihybrid cross was performed by Mendel to study the inheritance of two different traits simultaneously.

Which type of mutation results from a single base substitution in DNA?

Point mutation
Frameshift mutation
Chromosomal aberration
Polyploidy
1

A point mutation occurs when a single base is changed, as seen in sickle-cell anemia.

What is the function of the SRY gene located on the Y chromosome?

Determines female characteristics
Triggers male sex determination
Regulates blood clotting
Controls eye color
2

The SRY gene on the Y chromosome triggers male sex determination by promoting testes development.

Which process occurs during meiosis and increases genetic variation?

Crossing over
Mitosis
Replication
Transcription
1

Crossing over during meiosis exchanges genetic material between homologous chromosomes, increasing genetic diversity.

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

Mendel used Drosophila melanogaster for his experiments.
Mendel formulated the Law of Evolution.
Mendel's work was initially ignored by the scientific community.
Mendel studied inheritance only in animals.
3

Mendel's work was initially ignored but later recognized as the foundation of genetics.

Which of the following is an incorrect statement about sex determination?

Humans follow the XY sex determination system.
Birds follow the ZW sex determination system.
Insects such as grasshoppers use the XO system.
Mammals use the haplodiploidy system for sex determination.
4

Haplodiploidy is observed in insects like bees, not mammals.

Which of the following is an incorrect statement about Mendelian inheritance?

A monohybrid cross follows a 3:1 phenotypic ratio in the F2 generation.
Mendel’s laws are applicable only to plants.
The Law of Segregation explains how alleles separate during gamete formation.
Dihybrid crosses result in a 9:3:3:1 phenotypic ratio.
2

Mendel’s laws apply to all sexually reproducing organisms, not just plants.

What is the function of a Punnett square in genetics?

To analyze DNA sequences
To predict the probability of traits in offspring
To determine chromosome number
To identify mutations in genes
2

A Punnett square is used to predict the probability of offspring inheriting particular traits.

Which genetic disorder is caused by the absence of an X chromosome in females?

Down’s syndrome
Turner’s syndrome
Klinefelter’s syndrome
Sickle-cell anemia
2

Turner’s syndrome occurs due to the absence of one X chromosome, leading to a 45, XO karyotype.

Which disorder is caused due to the deletion of a small portion of chromosome 5?

Down’s syndrome
Turner’s syndrome
Cri-du-chat syndrome
Klinefelter’s syndrome
3

Cri-du-chat syndrome is caused by a deletion in the short arm of chromosome 5.

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