Previous Year Papers NEET Biology Class 12 – Molecular Basis of Inheritance

Molecular Basis of Inheritance is a crucial chapter of NEET Biology Class 12 that explains the structure and function of nucleic acids, mechanisms of DNA replication, transcription, translation, and regulation of gene expression. Mastery of this chapter is essential for answering both theoretical and diagram-based NEET questions.

NEET previous year papers frequently include questions on DNA and RNA structure, genetic code, protein synthesis, and mutations. Practicing PYQs helps students strengthen understanding of molecular genetics. Studentbro.in provides exam-focused material for effective preparation.

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DNA and RNA Structure – NEET PYQ Focus

• DNA (Deoxyribonucleic Acid) – Double helix structure, antiparallel strands, complementary base pairing (A-T, G-C).

• RNA (Ribonucleic Acid) – Single-stranded, types include mRNA, tRNA, rRNA; uracil replaces thymine.

NEET questions often test differences between DNA and RNA, nucleotide composition, and structural features.

DNA Replication – Important NEET Concepts

DNA replication is semi-conservative, occurring in the S-phase of the cell cycle. Key steps include:

• Unwinding of DNA – Helicase enzyme.

• Primer Formation – RNA primers by primase.

• Elongation – DNA polymerase synthesizes new strands.

• Termination – Removal of primers, ligation of Okazaki fragments on lagging strand.

Previous year papers frequently ask about enzymes, mechanism, and semi-conservative replication.

Transcription – Key Concepts

Transcription is the synthesis of RNA from DNA template:

• Occurs in nucleus.

• mRNA carries genetic code to ribosome.

• Involves initiation, elongation, and termination phases.

NEET PYQs often test steps, RNA polymerase function, and differences between DNA replication and transcription.

Translation – Protein Synthesis

Translation occurs in ribosomes and involves converting mRNA sequence into amino acids:

• Codons on mRNA are read by tRNA carrying amino acids.

• Formation of polypeptide chain occurs via peptide bonds.

• Process includes initiation, elongation, and termination.

Previous year questions often include genetic code features, codon recognition, and translation process diagrams.

Regulation of Gene Expression

• Prokaryotic Cells – Operon model (lac operon, trp operon).

• Eukaryotic Cells – Transcription factors, epigenetic modifications.

NEET PYQs may test differences in gene regulation between prokaryotes and eukaryotes.

Mutations – Source of Variation

Mutations are changes in nucleotide sequence that can affect protein synthesis:

• Point Mutation – Single base substitution (silent, missense, nonsense).

• Frameshift Mutation – Insertion or deletion causing reading frame shift.

NEET questions often ask about types, causes, and effects of mutations.

Chromosomal Basis of Inheritance

• Linkage and Crossing Over – Genes on the same chromosome can be inherited together; crossing over increases variation.

• Chromosomal Disorders – Structural and numerical changes affecting inheritance.

Previous year papers may include problems on linkage, recombination frequency, and pedigree analysis.

Importance of Previous Year Papers for NEET Biology

Practicing previous year papers helps students identify frequently asked topics, reinforce conceptual understanding, and improve speed. PYQs for Molecular Basis of Inheritance focus on DNA/RNA structure, replication, transcription, translation, gene regulation, and mutations.

Conclusion

Previous Year Papers of NEET Biology Class 12 Molecular Basis of Inheritance are essential for mastering molecular genetics. This chapter requires clear understanding of DNA and RNA structure, replication, transcription, translation, gene regulation, and mutations.

Regular practice of PYQs helps students enhance conceptual clarity, diagram interpretation, and problem-solving skills. Studentbro.in provides structured, reliable, and exam-focused content to help NEET aspirants succeed.