Molecular Basis of Inheritance Practice Questions

Class 12 · Biology · 2387 free MCQs with instant results and detailed explanations.

2387

Total

719

Easy

1181

Medium

487

Hard

Start Practicing Molecular Basis of Inheritance

Take a timed quiz or customize your practice session

Quick Quiz (10 Qs) → Mock Test (25 Qs) ⚙ Customize

Topics in Molecular Basis of Inheritance

Transcription 492

Translation 482

Replication 479

DNA Structure 470

Genetic Code 464

Sample Questions from Molecular Basis of Inheritance

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Easy

What is the shape of the DNA molecule?

A. Double helix

B. Single strand

C. Triple helix

D. Circular

Show Answer & Explanation

Correct Answer: A

The DNA molecule is characterized by its double helix structure, which consists of two strands that coil around each other.

Easy

Which of the following nitrogenous bases is not found in DNA?

A. Adenine

B. Thymine

C. Uracil

D. Cytosine

Show Answer & Explanation

Correct Answer: C

Uracil is found in RNA, while DNA contains thymine instead.

Easy

What type of bond holds the two strands of DNA together?

A. Ionic bonds

B. Hydrogen bonds

C. Covalent bonds

D. Metallic bonds

Show Answer & Explanation

Correct Answer: B

Hydrogen bonds between the complementary base pairs hold the two strands of DNA together.

Medium

Which of the following is NOT a characteristic of the DNA double helix structure?

A. Antiparallel strands

B. Uniform diameter

C. Right-handed twist

D. Single-stranded nature

Show Answer & Explanation

Correct Answer: D

DNA is double-stranded, forming a double helix, not single-stranded.

Medium

What type of bond holds the nucleotides together in a single strand of DNA?

A. Hydrogen bonds

B. Ionic bonds

C. Phosphodiester bonds

D. Covalent bonds

Show Answer & Explanation

Correct Answer: C

Nucleotides are linked by phosphodiester bonds between the phosphate group and the sugar.

Medium

Which base pairs with adenine in DNA?

A. Guanine

B. Thymine

C. Cytosine

D. Uracil

Show Answer & Explanation

Correct Answer: B

In DNA, adenine pairs with thymine through two hydrogen bonds.

Medium

What is the role of the sugar-phosphate backbone in DNA?

A. Provides genetic information

B. Stabilizes the double helix structure

C. Facilitates base pairing

D. Acts as a template for RNA synthesis

Show Answer & Explanation

Correct Answer: B

The sugar-phosphate backbone provides structural stability to the DNA molecule.

Hard

Which of the following statements about DNA structure is true?

A. DNA is a double helix made of nucleotide chains.

B. DNA contains uracil instead of thymine.

C. DNA is single-stranded in prokaryotes.

D. DNA is composed of ribonucleotides.

Show Answer & Explanation

Correct Answer: A

DNA is indeed a double helix structure formed by two long chains of nucleotides.

Hard

Which of the following describes the concept of complementary base pairing in DNA?

A. A pairs with G, and C pairs with T.

B. A pairs with T, and C pairs with G.

C. A pairs with C, and T pairs with G.

D. A pairs with T, and G pairs with C.

Show Answer & Explanation

Correct Answer: B

In DNA, adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G).

Q10

Hard

What is the role of hydrogen bonds in the structure of DNA?

A. They stabilize the sugar-phosphate backbone.

B. They form the base pairs between nucleotides.

C. They connect the histones to DNA.

D. They assist in DNA replication.

Show Answer & Explanation

Correct Answer: B

Hydrogen bonds form between the nitrogenous bases, stabilizing the base pairs in the double helix.

Showing 10 of 2387 questions. Start a quiz to practice all questions with scoring and timer.

Practice All 2387 Questions →

More Biology Chapters

1 Reproduction in Organisms

2399 Qs →

2 Sexual Reproduction in Flowering Plants

2383 Qs →

3 Human Reproduction

2387 Qs →

4 Reproductive Health

2386 Qs →

5 Principles of Inheritance and Variation

2421 Qs →

6 Evolution

2714 Qs →

7 Human Health and Disease

2975 Qs →

8 Strategies for Enhancement in Food Production

2865 Qs →

Other Class 12 Subjects

🧪 Chemistry → 📐 Mathematics → ⚡ Physics →

Molecular Basis of Inheritance — Class 12 Biology Practice Questions Online

This page contains 2387 practice MCQs for the chapter Molecular Basis of Inheritance in Class 12 Biology. The questions are organized by difficulty — 719 easy, 1181 medium, 487 hard — so you can choose the right level for your preparation.

Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 5 topics, giving you comprehensive coverage of the entire chapter.