CUET UG Categorised PYQ Biology Unit 10 -

📚

CUET UG Categorised PYQ Biology Unit 10

BIOLOGY

⏱️ 30 Minutes

❓ 13 Questions

📅 2022, 2023, 2024 & 2025

✍️ Long Answers

📌 Answers are locked once submitted — results and explanations appear at the end.

CUET UG Categorised PYQ Biology Unit 10

1 / 13

QUESTION 1 OF 13

'Golden rice' variety of rice shows: (PYQ 2022 Shift 1)

Answer Review

1 'Golden rice' variety of rice shows: (PYQ 2022 Shift 1)

A enhanced nutritional value of food

B less post-harvest losses of food

C tolerance to abiotic stress

D pest resistance

💡 Short Explanation

Rich in β-carotene. Helps prevent Vitamin A deficiency. Biofortified crop.

✅ Correct Answer Explanation

Golden Rice is a genetically modified rice variety enriched with β-carotene, a precursor of Vitamin A. It was developed to improve the nutritional quality of food.

❓ Why Other Options Are Incorrect

Option B) Not its primary objective.
Option C) Not developed for stress tolerance.
Option D) Not designed for pest resistance.

🎯 Strategy

Used: NCERT Recall

Option A → Correct.
Option B → Incorrect.
Option C → Incorrect.
Option D → Incorrect.

Final Answer → Enhanced nutritional value.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: Biofortification.

2 Which of the following is NOT an application of PCR? (PYQ 2022 Shift 1)

A Paternity testing

B Detection of mutations of genes in suspected cancer patient

C Powerful technique to identify genetic disorder

D To cure ADA (adenosine deaminase) deficiency

💡 Short Explanation

PCR is a diagnostic and amplification technique. ADA deficiency is treated through gene therapy. PCR does not cure diseases.

✅ Correct Answer Explanation

PCR is used for DNA amplification, mutation detection, paternity testing and diagnosis of genetic disorders. ADA deficiency is treated using gene therapy, not PCR.

❓ Why Other Options Are Incorrect

Option A) PCR helps establish paternity.
Option B) PCR detects mutations.
Option C) PCR is widely used in genetic diagnosis.

🎯 Strategy

Used: Odd One Out

Option A → PCR application.
Option B → PCR application.
Option C → PCR application.
Option D → Gene therapy application.

Final Answer → ADA deficiency cure.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: PCR Applications.

3 Complementary ds RNA which prevents translation is formed in ______. (PYQ 2022 Shift 1)

A PCR

B RNA interference

C Gene therapy

D ELISA

💡 Short Explanation

dsRNA triggers gene silencing. mRNA gets degraded. Translation is blocked.

✅ Correct Answer Explanation

RNA interference (RNAi) is a biological process in which double-stranded RNA suppresses gene expression by degrading complementary mRNA, thereby preventing translation.

❓ Why Other Options Are Incorrect

Option A) PCR amplifies DNA.
Option C) Gene therapy replaces or modifies genes.
Option D) ELISA detects antigens or antibodies.

🎯 Strategy

Used: NCERT Recall

Option A → DNA amplification.
Option B → Correct.
Option C → Gene correction.
Option D → Diagnostic test.

Final Answer → RNA interference.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: RNA Interference.

4 With reference to uses of transgenic animals, identify the incorrect statement: (PYQ 2023 Shift 1)

A To study disease

B To test vaccine safety

C To test chemical safety

D To make better quality seeds

💡 Short Explanation

Transgenic animals are animals. Seeds are produced by plants. Seed improvement is not their use.

✅ Correct Answer Explanation

Transgenic animals are used to study disease mechanisms, test vaccine safety and evaluate chemical toxicity. Producing better quality seeds is related to transgenic plants and plant breeding, not transgenic animals.

❓ Why Other Options Are Incorrect

Option A) Valid use of transgenic animals.
Option B) Used for vaccine safety testing.
Option C) Used for toxicity and chemical safety testing.

🎯 Strategy

Used: Odd One Out

Option A → Animal application.
Option B → Animal application.
Option C → Animal application.
Option D → Plant-related application.

Final Answer → Better quality seeds.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: Transgenic Animals.

5 The bacterium used by 'Eli Lilly', an American Company, to produce insulin chains is: (PYQ 2023 Shift 1)

A Bacillus thuringiensis

B Agrobacterium tumefaciens

C Escherichia coli

D Streptococcus pneumoniae

💡 Short Explanation

First commercial recombinant insulin. Human insulin gene inserted into E. coli. Used by Eli Lilly.

✅ Correct Answer Explanation

Eli Lilly produced recombinant human insulin (Humulin) using genetically engineered Escherichia coli. Genes coding for insulin chains A and B were inserted into E. coli, which synthesized the insulin chains that were later combined to form functional insulin.

❓ Why Other Options Are Incorrect

Option A) Bacillus thuringiensis → Used for Bt toxin production.
Option B) Agrobacterium tumefaciens → Plant genetic engineering vector.
Option D) Streptococcus pneumoniae → Disease-causing bacterium, not used for insulin production.

🎯 Strategy

Used: NCERT Recall

Option A → Bt crops.
Option B → Plant transformation.
Option C → Recombinant insulin production.
Option D → Human pathogen.

Final Answer → Escherichia coli.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: Production of Human Insulin.

6 Which of the following statements regarding GMOs are not correct? (PYQ 2023 Shift 1)
(A) Crops are more tolerant to abiotic stress
(B) Pest-resistant crops
(C) Post harvest losses are more
(D) Reduced efficiency of mineral usage

A (A) and (B) only

B (A) and (C) only

C (C) and (D) only

D (B) and (D) only

💡 Short Explanation

GM crops reduce post-harvest losses. Improve mineral utilization. A and B are benefits.

✅ Correct Answer Explanation

Genetically modified crops are developed to increase tolerance to abiotic stresses, provide pest resistance, reduce post-harvest losses and improve nutrient utilization. Therefore statements (C) and (D) are incorrect.

❓ Why Other Options Are Incorrect

Option A) A and B are correct statements.
Option B) A is correct, not incorrect.
Option D) B is correct.

🎯 Strategy

Used: Elimination

Option A → Includes correct statements.
Option B → Includes correct statement A.
Option C → Both incorrect statements.
Option D → Includes correct statement B.

Final Answer → Option C.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: Advantages of GM Crops.

7 Toxin of Bacillus thuringiensis is activated in insect by: (PYQ 2023 Shift 2)

A Alkaline pH of gut

B Acidic pH of gut

C High temperature

D Mechanical action of gut

💡 Short Explanation

Bt toxin is produced as inactive protoxin. Insect gut is alkaline. Alkaline pH activates toxin.

✅ Correct Answer Explanation

Bacillus thuringiensis produces an inactive protoxin. When susceptible insect larvae consume it, the alkaline pH of their gut converts the protoxin into an active toxin. This toxin damages the gut epithelium, causing death of the insect.

❓ Why Other Options Are Incorrect

Option B) Insect gut is alkaline, not acidic.
Option C) Temperature does not activate Bt toxin.
Option D) Mechanical action is not responsible.

🎯 Strategy

Used: NCERT Recall

Option A → Correct.
Option B → Wrong pH.
Option C → Unrelated.
Option D → Unrelated.

Final Answer → Alkaline pH.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: Bt Crops.

8 In RNAi genes are silenced by: (PYQ 2023 Shift 2)

A ss RNA

B ss DNA

C ds RNA

D ds DNA

💡 Short Explanation

RNA interference uses double-stranded RNA. Prevents expression of target gene. Causes mRNA degradation.

✅ Correct Answer Explanation

RNA interference (RNAi) is a process in which double-stranded RNA (dsRNA) initiates degradation of complementary mRNA molecules, thereby preventing gene expression.

❓ Why Other Options Are Incorrect

Option A) Single-stranded RNA does not initiate RNAi.
Option B) DNA is not involved in RNAi mechanism.
Option D) Double-stranded DNA does not trigger RNAi.

🎯 Strategy

Used: NCERT Recall

Option A → Incorrect.
Option B → Incorrect.
Option C → Correct.
Option D → Incorrect.

Final Answer → dsRNA.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: RNA Interference.

9 RNA interference process occurs in ______ as a method of cellular defence. (PYQ 2023 Shift 3)

A Prokaryotes only

B Unicellular eukaryotes

C Multicellular eukaryotes

D All eukaryotes

💡 Short Explanation

RNAi is a eukaryotic defence mechanism. NCERT discusses it in nematodes. Used against parasitic genes and viruses.

✅ Correct Answer Explanation

RNA interference (RNAi) is a cellular defence mechanism found in multicellular eukaryotes. Double-stranded RNA triggers degradation of complementary mRNA, thereby silencing specific genes.

❓ Why Other Options Are Incorrect

Option A) Not limited to prokaryotes.
Option B) NCERT specifically highlights multicellular eukaryotes.
Option D) Not the NCERT-specific answer.

🎯 Strategy

Used: NCERT Recall

Option A → Incorrect.
Option B → Incomplete.
Option C → Correct.
Option D → Broader than NCERT answer.

Final Answer → Multicellular eukaryotes.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: RNA Interference.

10 In which year an American company got patent rights on Basmati rice through US Patent and Trademark Office? (PYQ 2023 Shift 3)

A 1987

B 2010

C 1995

D 1997

💡 Short Explanation

Basmati patent controversy involved RiceTec. Patent granted by US Patent and Trademark Office. NCERT mentions 1997.

✅ Correct Answer Explanation

In 1997, the American company RiceTec obtained patent rights related to Basmati rice from the US Patent and Trademark Office. This became a major biopiracy controversy and India challenged several claims successfully.

❓ Why Other Options Are Incorrect

Option A) 1987 → Patent issue had not arisen.
Option B) 2010 → Much later than the actual event.
Option C) 1995 → Incorrect year.

🎯 Strategy

Used: NCERT Recall

Option A → Incorrect year.
Option B → Incorrect year.
Option C → Incorrect year.
Option D → Correct year.

Final Answer → 1997.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Biotechnology and its Applications → Section/Theme: Biopiracy.

11 Transgenic animals are used to understand the contribution of genes in the development of diseases such as: (PYQ 2025 Shift 1)

A Cholera and typhoid

B Elephantiasis and ringworm

C Cancer and cystic fibrosis

D Pneumonia and kala-azar

💡 Short Explanation

Transgenic animals model genetic diseases. Used in biomedical research. Help study disease mechanisms.

✅ Correct Answer Explanation

Transgenic animals are genetically modified to carry specific genes and are extensively used to study gene function and disease development. Diseases such as cancer and cystic fibrosis have strong genetic components and can be effectively studied using transgenic animal models. These models help researchers understand disease progression and test therapies.

❓ Why Other Options Are Incorrect

Option A) Cholera and typhoid → Primarily infectious bacterial diseases.
Option B) Elephantiasis and ringworm → Parasitic and fungal diseases.
Option D) Pneumonia and kala-azar → Primarily infectious diseases.

🎯 Strategy

Used: Contextual/Tonal Matching

Option A → Infectious diseases.
Option B → Non-genetic disorders.
Option C → Genetic disease models.

Final Answer → Based on application of transgenic animals.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Biotechnology and its Applications → Section/Theme: Transgenic Animals.

12 Genetically modified plants have been useful in: (PYQ 2025 Shift 1)

A Increasing post harvest losses

B Decreasing crop yield

C Making crops tolerant to stresses

D Decreasing efficiency of mineral usage by plants

💡 Short Explanation

GM crops resist environmental stress. Improve productivity. Enhance agricultural performance.

✅ Correct Answer Explanation

Genetically modified plants are engineered to tolerate abiotic stresses such as drought, salinity, heat, and cold. They may also resist pests and diseases, improve nutrient use efficiency, and reduce post-harvest losses. Therefore, making crops tolerant to stresses is one of the major advantages of GM technology.

❓ Why Other Options Are Incorrect

Option A) Increasing post harvest losses → GM crops are designed to reduce such losses.
Option B) Decreasing crop yield → GM technology aims to improve productivity.
Option D) Decreasing efficiency of mineral usage by plants → GM crops often improve nutrient utilization.

🎯 Strategy

Used: Elimination

Option A → Opposite of GM objective.
Option B → Contradicts agricultural goals.
Option C → Major benefit of GM crops.

Final Answer → Based on elimination.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Biotechnology and its Applications → Section/Theme: Genetically Modified Crops.

13 Which of the following controls the growth of bollworms? (PYQ 2024 Shift 1)

A CryIAc and CryIIAb genes

B CryIAb gene

C RNAi

D dsRNA

💡 Short Explanation

Bt cotton contains Cry genes. Effective against cotton bollworms. CryIAc and CryIIAb provide protection.

✅ Correct Answer Explanation

Bt cotton contains CryIAc and CryIIAb genes derived from Bacillus thuringiensis. These genes produce insecticidal proteins that specifically kill cotton bollworms while remaining harmless to humans.

❓ Why Other Options Are Incorrect

Option B) CryIAb gene → Used mainly against corn borer.
Option C) RNAi → RNAi is used against nematodes.
Option D) dsRNA → dsRNA mediates RNAi, not Bt bollworm control.

🎯 Strategy

Used: Elimination

Option A → Bt cotton bollworm resistance.
Option B → Different target insect.
Option C → Nematode control.
Option D → RNAi mechanism.

Final Answer → Option A.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Biotechnology and its Applications → Section/Theme: Bt Crops.

CUET UG Categorised PYQ Biology Unit 10

Test Complete!

Answer Review