The NCERT Solutions for Class 12 Biotechnology Chapter 3 Gene Cloning cover all 17 exercise questions, according to the latest 2026-27 NCERT textbook. Each answer explains DNA isolation, restriction enzymes, recombinant screening, blotting, PCR and DNA libraries in simple exam language.
- Question count: 17 solved NCERT exercise questions with MCQ answer checks.
- Best for: board revision, viva preparation and quick gene cloning recap.
- PDF includes: stepwise solutions, expert explanations and boxed final answers.
Student Feedback: Students revising Gene Cloning said the MCQs became easier after grouping lacZ, blotting, PCR and library questions by technique.
Class 12 Biotechnology Chapter 3 Gene Cloning Solutions PDF
Class 12 Biotechnology Chapter 3 Gene Cloning NCERT Solutions help students revise the complete cloning pathway. The chapter starts with candidate gene identification, then moves to DNA extraction, restriction enzymes, ligation, host transfer and screening.
Most students lose marks in this chapter when they mix up Southern, Northern and Western blotting. The PDF keeps those differences in one clean explanation.
How to Use These Gene Cloning NCERT Solutions
Start with the short answer questions on DNA isolation and enzymes. Then revise the MCQs on lacZ, blotting and restriction enzymes. Finish with PCR and DNA libraries because those answers connect many chapter ideas.
- Use the boxed answer for last-minute recall.
- Read the expert answer when you need the reasoning behind an MCQ.
- Revise the comparison tables before school tests.
Gene Cloning Workflow for Class 12 Biotechnology
Gene cloning follows a fixed order. First, the candidate gene is identified. Next, nucleic acid is isolated and cut with suitable enzymes. The insert is joined to a vector and transferred into a host. Finally, recombinants are screened.
| Step | What Happens | Why It Matters |
|---|---|---|
| Isolation | DNA is released and purified | Gives clean nucleic acid for cloning |
| Restriction digestion | DNA is cut at specific sequences | Creates controlled ends for ligation |
| Ligation | Insert joins with vector DNA | Forms recombinant DNA |
| Transfer | Vector enters host cell | Host copies or expresses the insert |
| Screening | Recombinants are identified | Separates useful clones from others |
Important MCQ Answers in Gene Cloning
The chapter has five direct MCQ-style items. The most important answers are: lacZ expression for blue-white selection, Western blot for protein detection, PstI source mismatch, 6.4 x 109 base pairs for diploid human genome and EcoRI as Type II.
In a small student feedback check, most students said these MCQs became easier after they grouped them by technique. Use the image below before solving the exercise again.
Blotting, PCR and Library Revision Map
Southern blotting detects DNA, Northern blotting detects RNA and Western blotting detects proteins. PCR amplifies a target DNA segment by denaturation, annealing and extension. Genomic libraries represent the whole genome, while cDNA libraries represent expressed genes from a tissue.
Gene Cloning Video Revision
Source: NCERT Wallah on YouTube
Check All Gene Cloning Exercise Answers
The solved question cards below let students open the main solution and expert solution separately.
Practice mode: Open the question-wise Gene Cloning solutions cards.
Related Class 12 Biotechnology Resources
| Resource | Use it for |
|---|---|
| Gene Cloning NCERT Book PDF | Read the official chapter before solving. |
| Gene Cloning Notes | Revise definitions and processes quickly. |
| Gene Cloning Handwritten Notes | Use for one-shot exam recap. |
All Class 12 Biotechnology NCERT Solutions
| Chapter | NCERT Solutions |
|---|---|
| Chapter 1 An Overview of Recombinant DNA Technology | Open Chapter 1 Solutions |
| Chapter 2 Host-Vector System | Open Chapter 2 Solutions |
| Chapter 3 Gene Cloning | Open Chapter 3 Solutions |
Gene Cloning Biotechnology NCERT Solutions FAQs
Ques. What is covered in Class 12 Biotechnology Chapter 3 Gene Cloning NCERT Solutions?
Ans. The solutions cover DNA isolation, restriction enzymes, DNA transfer, recombinant screening, blotting, PCR, genomic libraries and cDNA libraries.
Ques. Which blot detects proteins in Gene Cloning?
Ans. Western blotting detects specific proteins. Southern blotting detects DNA, while Northern blotting detects RNA.
Ques. What is the correct answer for blue-white selection?
Ans. Blue-white selection is based on lacZ gene expression. Recombinant colonies usually remain white when the insert disrupts lacZ.
Ques. What is the difference between genomic and cDNA libraries?
Ans. A genomic library represents the whole genome. A cDNA library represents expressed genes made from mRNA of a particular tissue or cell type.
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