Are these practice questions for Molecular Basis of Inheritance based on the CBSE pattern?

Yes. Every practice question is modeled on the CBSE Class 12 - Science Biology exam pattern — including MCQs, assertion-reason questions, and short-answer formats that frequently appear in CBSE papers.

Are the practice questions for Molecular Basis of Inheritance free?

Yes. Every chapter includes free practice questions for Class 12 - Science students to get you started.

What types of questions are included?

The practice set for Molecular Basis of Inheritance mainly includes MCQs and CBSE-style short-answer questions, with instant feedback on each answer. For full-length textbook practice, use the NCERT Solutions page.

Are the practice questions suitable for board exam preparation?

Yes. The questions test the same concepts and depth that CBSE asks in board exams. After finishing, also solve the NCERT and NCERT Exemplar exercises for Molecular Basis of Inheritance for full coverage.

How many practice questions are there for Molecular Basis of Inheritance?

The number scales with chapter length and concept density. Each chapter typically has 15-50 practice questions across MCQ and short-answer formats.

Molecular Basis of Inheritance Class 12 Biology Practice Questions with Answers

easy

Propose why a single DNA-dependent RNA polymerase is sufficient for all transcription in prokaryotes, whereas eukaryotes require three distinct types.

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easy

Define a nucleoside.

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easy

Name the positively charged proteins that help in the packaging of DNA in eukaryotes.

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easy

Apply your knowledge of tRNA to explain how the codons UUU and UUC can both code for the amino acid Phenylalanine.

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easy

The DNA of E. coli has

4.6 \times 10^6

base pairs. Calculate the length of this DNA molecule in millimeters (mm), given that the distance between two consecutive base pairs is

0.34

nm.

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easy

List the three major types of RNA needed to synthesise a protein in a cell.

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easy

Identify the inducer molecule in the lac operon.

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easy

Propose a reason why, during transcription, only one of the two DNA strands acts as a template.

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easy

Name the enzyme responsible for joining the discontinuously synthesized fragments during DNA replication.

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easy

A point mutation occurs in the third base of a codon for the amino acid Leucine (e.g., CUU). Often, this mutation does not change the resulting amino acid. Justify this observation using the properties of the genetic code and evaluate its significance for the stability of the proteome.

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medium

Analyze what Hershey and Chase would have concluded if their experiment had shown that both radioactive phosphorus (

^{32}P

) and radioactive sulfur (

^{35}S

) were found inside the bacterial cells after centrifugation.

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medium

Formulate a hypothesis to explain why the genetic code is degenerate. Justify how this property might provide an evolutionary advantage by conferring resistance to certain point mutations.

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medium

If a double-stranded DNA molecule has 30% guanine, list the percentages of the other three nitrogenous bases.

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medium

A child's DNA fingerprint is compared with that of its mother and two potential fathers. The mother's DNA fingerprint matches the child for three specific VNTR loci. Demonstrate how you would use the remaining bands in the child's fingerprint to identify the biological father from the two candidates. Explain the principle of inheritance you are applying.

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medium

Compare and contrast the template strand and the coding strand of a DNA transcription unit with respect to their polarity and role in transcription.

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medium

If the length of an E. coli DNA molecule is

1.36 \text{ mm}

, and the distance between two consecutive base pairs is

0.34 \text{ nm}

, calculate the number of base pairs. Evaluate the complexity of packaging this DNA within a microscopic cell and propose the name of the structure that helps achieve this in prokaryotes.

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medium

Critique the use of the term 'coding strand' for the DNA strand that is not transcribed. Justify your answer.

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medium

Explain the concept of a 'degenerate' genetic code.

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medium

A eukaryotic gene has 5 exons and 4 introns. The total length of the pre-processed hnRNA is 5000 base pairs. After splicing, the mature mRNA is only 1500 base pairs long. Calculate the total length of the introns and formulate a hypothesis explaining a potential functional significance of these non-coding introns.

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medium

Summarize the roles of the promoter and terminator sequences in a transcription unit.

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medium

The haploid content of human DNA is

3.3 \times 10^9

bp. If a typical nucleosome contains 200 bp of DNA helix, calculate the approximate number of nucleosomes present in a diploid human cell.

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medium

Explain the dual function of the codon AUG.

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medium

Design an experiment based on the Hershey-Chase model to determine if a newly discovered bacteriophage uses protein or nucleic acid as its genetic material. Justify each step of your experimental design.

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medium

Analyze how the identification of about 1.4 million Single Nucleotide Polymorphisms (SNPs) from the Human Genome Project can be applied in medical diagnostics.

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medium

You are given a DNA sample from a crime scene and DNA from two suspects (A and B). Design a workflow using the principles of DNA fingerprinting (VNTR analysis) to identify the culprit. Your design should outline the key steps from DNA isolation to the final interpretation.

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medium

A segment of double-stranded DNA is found to have 22% guanine. Calculate the percentage of adenine in this DNA segment.

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medium

A polypeptide chain has the sequence Met-Phe-Phe-Phe. Analyze why it is difficult to predict the exact corresponding mRNA nucleotide sequence, and demonstrate this difficulty by providing two possible mRNA sequences.

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medium

A scientist discovers a new virus with an RNA genome. To replicate, it must first synthesize DNA from its RNA. Propose a name for this process and justify the necessity of a specific enzyme for this conversion, drawing a parallel to the central dogma.

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medium

Describe the five salient features of the DNA double helix model proposed by Watson and Crick.

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medium

Recall the full form of HGP and VNTR as used in the context of molecular biology.

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medium

Describe the process of splicing in eukaryotes.

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medium

Evaluate the ethical, legal, and social implications (ELSI) that might arise from the data generated by the Human Genome Project. Propose two guidelines a government could implement to mitigate potential misuse of an individual's genetic information.

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medium

Evaluate the statement: "RNA, being unstable and catalytic, was a 'draft' of the genetic material, while DNA is the 'final version'." Justify your evaluation based on the chemical properties of both molecules and the 'RNA World' hypothesis.

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medium

Critique the "one gene-one enzyme" hypothesis in the context of split genes found in eukaryotes and polycistronic structural genes in prokaryotes. Justify why a more modern definition of a gene is required.

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medium

Summarize the key findings or salient features of the Human Genome Project.

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medium

Compare the chemical structures of DNA and RNA to analyze why DNA is a more stable molecule for storing genetic information.

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hard

Design an experiment to prove that DNA replication is semiconservative, different from the Meselson-Stahl experiment. Propose a method using a fluorescent tag instead of heavy isotopes, and justify how your expected results would support the hypothesis.

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hard

A pharmaceutical company aims to create a drug that specifically inhibits the lac operon in E. coli even in the presence of lactose. Propose two distinct molecular mechanisms by which such a drug could function, and evaluate the potential specificity of each approach.

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hard

In the Meselson and Stahl experiment, E. coli was grown in a medium containing

^{15}N

and then transferred to a medium with

^{14}N

. If E. coli divides every 20 minutes, analyze the proportions of light (

^{14}N/^{14}N

), hybrid (

^{15}N/^{14}N

), and heavy (

^{15}N/^{15}N

) DNA molecules after 60 minutes of growth in the

^{14}N

medium.

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hard

Analyze the consequences for the expression of the lac operon in E. coli if the regulatory gene (i gene) undergoes a mutation that results in a non-functional repressor protein. Consider both the absence and presence of lactose in the medium.

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hard

Examine the consequences for transcription if the promoter and terminator sequences of a gene were swapped in position.

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hard

Examine the potential consequences on the final protein product if a point mutation occurs at the 3'-end of an intron, changing the sequence that is recognized by the splicing machinery in a eukaryotic gene.

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hard

Explain the experimental steps of the Hershey-Chase experiment that proved DNA is the genetic material.

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hard

Describe the structure and function of a tRNA molecule, also known as the adapter molecule.

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hard

Examine the effect of a single base deletion at the 7th position in the following DNA template strand sequence on the resulting amino acid sequence:

3'

-TAC AAG TCG GAT ACT-

5'

. Use the provided mRNA codons: AUG (Met), UUC (Phe), AGC (Ser), CUA (Leu), UGA (Stop).

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Molecular Basis of InheritanceClass 12 Biology Practice Questions