Chapter Exam

Chapter 4: Principles of Inheritance and Variation — Online MCQ Test

Q: Which scientist proposed the chromosomal theory of inheritance?

Answer: A. Sutton and Boveri — Sutton and Boveri proposed that genes are located on chromosomes and that chromosomes behave in a way consistent with Mendel’s laws.

Q: In human beings, the sex of an individual is determined by which pair of chromosomes?

Answer: B. Sex chromosomes — In humans, sex is determined by the X and Y chromosomes, which are called sex chromosomes.

Q: If a father is colour blind and the mother is normal but a carrier, what is the chance of their son being colour blind?

Answer: C. 50% — A son receives the Y chromosome from his father and one X chromosome from his mother. If the mother is a carrier, there is a 50% chance of passing the affected X chromosome.

ZOOLOGY · CLASS 12th · Tamil Nadu State Board

Practice Chapter 4: Principles of Inheritance and Variation with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 12th ZOOLOGY. This chapter covers: Diving into classical genetics this chapter covers sex determination chromosomal disorders linkage crossing over and autosomal and sex-linked inheritance patterns in humans.. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 4: Principles of Inheritance and Variation — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 12th ZOOLOGY — Chapter 4: Principles of Inheritance and Variation, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which scientist proposed the chromosomal theory of inheritance?

A. Sutton and Boveri ✓
B. Watson and Crick
C. Mendel and Morgan
D. Darwin and Wallace

Answer: A. Sutton and Boveri
Sutton and Boveri proposed that genes are located on chromosomes and that chromosomes behave in a way consistent with Mendel’s laws.

In human beings, the sex of an individual is determined by which pair of chromosomes?

A. Autosomes
B. Sex chromosomes ✓
C. Homologous chromosomes
D. Somatic chromosomes

Answer: B. Sex chromosomes
In humans, sex is determined by the X and Y chromosomes, which are called sex chromosomes.

Which of the following best explains why linked genes are inherited together?

A. They are located on different chromosomes
B. They are located close to each other on the same chromosome ✓
C. They are always dominant
D. They undergo crossing over every time

Answer: B. They are located close to each other on the same chromosome
Genes that are close together on the same chromosome tend to be inherited together because the chance of crossing over between them is low.

If a father is colour blind and the mother is normal but a carrier, what is the chance of their son being colour blind?

A. 0%
B. 25%
C. 50% ✓
D. 100%

Answer: C. 50%
A son receives the Y chromosome from his father and one X chromosome from his mother. If the mother is a carrier, there is a 50% chance of passing the affected X chromosome.

Which of the following is the correct sequence of events in meiosis that leads to genetic recombination?

A. Crossing over in prophase I followed by segregation of homologous chromosomes ✓
B. Segregation of sister chromatids followed by crossing over in telophase II
C. Independent assortment in interphase followed by linkage in metaphase
D. Mutation in anaphase II followed by chromosome duplication

Answer: A. Crossing over in prophase I followed by segregation of homologous chromosomes
Recombination begins with crossing over during prophase I, and the resulting chromosomes are then separated during meiosis.