Class 12 Biology — Chapter 5: Molecular Basis of Inheritance
90 practice questions · 30 Easy · 30 Medium · 30 Hard
Practise Class 12 Biology Chapter 5, "Molecular Basis of Inheritance", with 90 NCERT-aligned multiple-choice questions. The set is split into 30 Easy, 30 Medium and 30 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams and NEET UG.
"Molecular Basis of Inheritance" is one of the chapters where diagram-based recall, terminology and NCERT line-by-line accuracy really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Molecular Basis of Inheritance, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 12 Biology mastery score. A few sample questions are shown below; sign in free to practise all 90.
Key concepts: Molecular Basis of Inheritance (Class 12 Biology)
This chapter covers DNA as the genetic material, its structure and replication, transcription, the genetic code, translation, and gene regulation (the lac operon).
- DNA as genetic material
- Established by the Griffith, Avery and Hershey–Chase experiments; DNA (not protein) carries genetic information.
- DNA structure
- Watson–Crick double helix: antiparallel strands, complementary base pairing (A=T, G≡C), with sugar-phosphate backbones.
- Replication
- Semi-conservative (Meselson–Stahl); DNA polymerase synthesises a new strand 5'→3' using each old strand as template.
- Central dogma
- DNA → RNA (transcription) → protein (translation); the genetic code is triplet, degenerate and (nearly) universal.
- Gene regulation
- The lac operon is an example of regulation in prokaryotes — switched on/off depending on the substrate (lactose).
💡 Exam tips for Molecular Basis of Inheritance
- DNA replication is semi-conservative — each daughter molecule keeps one parental strand.
- Remember the code is degenerate (many codons per amino acid) but unambiguous (one codon → one amino acid).
Sample questions
DNA double helix model proposed by:
1953, with Franklin's X-ray data.
Codon is:
64 codons total.
PCR is used to:
Polymerase Chain Reaction.
Molecular Basis of Inheritance — FAQs
What are the key concepts in Class 12 Biology Molecular Basis of Inheritance?+
This chapter covers DNA as the genetic material, its structure and replication, transcription, the genetic code, translation, and gene regulation (the lac operon). Key ideas include DNA as genetic material, DNA structure, Replication, Central dogma, Gene regulation.
What does Class 12 Biology Chapter 5 (Molecular Basis of Inheritance) cover on XamBaaz?+
It covers 90 NCERT-aligned MCQs on "Molecular Basis of Inheritance" — 30 Easy, 30 Medium and 30 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams and NEET UG.
Are these "Molecular Basis of Inheritance" questions free to practise?+
Yes — sign in with Google to practise "Molecular Basis of Inheritance" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Molecular Basis of Inheritance" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
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