Class 12 Biology: Molecular Basis of Inheritance - Hard Worksheet
This worksheet challenges your understanding of complex concepts in the molecular basis of inheritance, including DNA replication, transcription, translation, and genetic regulation.
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- Q1.Which of the following statements about the Lac operon is INCORRECT?
- A.The repressor protein binds to the operator region in the absence of lactose.
- B.Allolactose acts as an inducer by binding to the repressor protein.
- C.Transcription of structural genes occurs when glucose is available and lactose is absent.
- D.The lacY gene codes for permease, which facilitates the entry of lactose into the cell.
- Q2.The process of unwinding DNA during replication requires energy, which is provided by the hydrolysis of _______.
- Q3.Explain the significance of degeneracy of the genetic code.
- Q4.In Meselson and Stahl's experiment, E. coli was grown in a medium containing 15N for several generations. When transferred to a 14N medium, what would be the composition of DNA molecules after two generations?
- A.All hybrid (15N/14N) DNA molecules.
- B.75% hybrid (15N/14N) and 25% light (14N/14N) DNA molecules.
- C.50% hybrid (15N/14N) and 50% light (14N/14N) DNA molecules.
- D.25% hybrid (15N/14N) and 75% light (14N/14N) DNA molecules.
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What's inside this workbook
This Class 12 Biology Practice contains 10 questions across 2 printable pages and includes a full answer key at hard difficulty. Aligned to the CBSE and NCERT syllabus.
How this worksheet helps your child
- Builds confidence in core Biology concepts taught in Class 12 through repeated, varied practice.
- Aligned to CBSE and NCERT — questions mirror the pattern children see in school tests and unit assessments.
- Comes with an answer key so parents and students can self-check in minutes, without needing a teacher.
- Pitched at hard level — use it for daily homework, weekend revision or quick exam warm-ups.
Topics covered
How to use this worksheet at home
Open the print view and use your browser's Print dialog to print on regular A4 paper or save as a PDF. Hand the printed sheet to your child (Class 12) and set a relaxed time limit — 15 to 25 minutes works for most Biology worksheets. When they're done, open the "With answer key" view and let them self-mark question by question. Re-print as many times as you need; the file never expires and there's no download limit.
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- Can I print this worksheet at home?
- Yes. Click "Open print view" and use your browser's Print dialog to print on standard A4 paper, or save it as a PDF for later. The layout is designed to fit cleanly without scaling.
- Does it include an answer key?
- Yes — click "With answer key" to print a version with answers included, so parents and students can self-mark in minutes.
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