NEET Biology: Biotechnology and its Applications questions with solutions

Q1. Which of the following is true for Golden rice?

1. It is vitamin A enriched, with a gene from daffodil.
2. It is pest resistant, with a gene from Bacillus thuringiensis.
3. It is drought tolerant, developed using Agrobacterium vector.
4. It has yellow grains, because of a gene introduced from a primitive variety of rice.

Answer: It is vitamin A enriched, with a gene from daffodil.

Golden rice is genetically modified to produce beta-carotene, a precursor of vitamin A, in the edible endosperm. One of the genes used in its development came from daffodil, which helps create the yellow color and vitamin A enrichment.

Q2. What triggers activation of protoxin to active Bt toxin of Bacillus thuringiensis in boll worm?

1. Body temperature
2. Moist surface of midgut
3. Alkaline pH of gut
4. Acidic pH of stomach

Answer: Alkaline pH of gut

Bt protoxin is activated in the insect midgut because the gut is strongly alkaline, which dissolves the crystal and allows proteolytic processing into the active toxin. Boll worm larvae have this alkaline gut environment, not an acidic stomach like mammals.

Q3. The crops engineered for glyphosate are resistant/tolerant to:

1. Bacteria
2. Insects
3. Herbicides
4. Fungi

Answer: Herbicides

Glyphosate is a broad-spectrum herbicide, so crops engineered for glyphosate are designed to tolerate herbicide application. This lets farmers spray weeds without harming the crop itself.

Q4. The genetic defect - Adenosine deaminase (ADA) deficiency may be cured permanently by:

1. administering adenosine deaminase activators.
2. introducing bone marrow cells producing ADA into cells at early embryonic stages.
3. enzyme replacement therapy.
4. periodic infusion of genetically engineered lymphocytes having functional ADA cDNA.

Answer: introducing bone marrow cells producing ADA into cells at early embryonic stages.

ADA deficiency is a genetic disorder, so a durable cure requires replacing the defective hematopoietic system with cells that can continuously produce ADA. Temporary measures like enzyme replacement or infusing engineered lymphocytes do not permanently correct the underlying defect.

Q5. In transgenics, expression of transgene in target tissue is determined by

1. enhancer
2. transgene
3. promoter
4. reporter

Answer: promoter

The promoter contains the regulatory information that directs transcription in specific tissues, so it determines where the transgene is expressed. The transgene is just the coding sequence, while a reporter only helps detect expression.

Q6. An improved variety of transgenic basmati rice

1. does not require chemical fertilizers and growth hormones
2. gives high yield and is rich in vitamin A
3. is completely resistant to all insect pests and diseases of paddy
4. gives high yield but has no characteristic aroma

Answer: gives high yield and is rich in vitamin A

Transgenic basmati rice can be engineered to increase yield and add a nutrient that the original grain lacks. The correct choice is the one that mentions both higher yield and vitamin A enrichment.

Q7. The first transgenic crop was

1. pea
2. flax
3. tobacco
4. cotton

Answer: tobacco

Tobacco was the first transgenic crop because it was one of the earliest plants successfully transformed using recombinant DNA methods. Its ease of genetic manipulation made it the standard test crop for early plant biotechnology.

Q8. Which of the following is likely to be achieved in the coming two decades?

1. A complete understanding of the brain-mind interaction
2. Control of cancer
3. Correction of genetic basis of diabetes mellitus
4. Production of biodegradable plastic rather than cellulose by higher plants

Answer: Correction of genetic basis of diabetes mellitus

Correcting the genetic basis of diabetes mellitus is the most plausible near-term achievement because advances in genomics, gene editing, and personalized medicine are rapidly moving toward targeted interventions. The other choices are either far more complex or too speculative to expect complete success within two decades.

Q9. Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is resistant to

1. (a) Fungal diseases
2. (b) Plant nematodes
3. (c) Insect predators
4. (d) Insect pests

Answer: (d) Insect pests

Bt cotton contains a gene from Bacillus thuringiensis that produces Bt toxin. This toxin is effective against certain insect larvae, so the plant becomes resistant to insect pests.

Q10. What is antisense technology?

1. A cell displaying a foreign antigen used for synthesis of antigens
2. Production of somaclonal variants in tissue cultures
3. When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene
4. RNA polymerase producing DNA

Answer: When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene

Antisense technology involves using a strand of RNA that is complementary to a specific mRNA to block its translation, thereby inhibiting the expression of a target gene.

Q11. Introduction of food plants developed by genetic engineering is not desirable because

1. economy of developing countries may suffer
2. these products are less tasty as compared to the already existing products
3. this method is costly
4. there is danger of entry of viruses and toxins with introduced crop

Answer: there is danger of entry of viruses and toxins with introduced crop

Genetically engineered food plants may pose risks such as the unintentional introduction of harmful viruses or toxins, which can have adverse effects on health and the environment.

Q12. Golden rice is a genetically modified crop plant where the incorporated gene is meant for biosynthesis of:

1. Vitamin C
2. Omega 3
3. Vitamin A
4. Vitamin B

Answer: Vitamin A

Golden rice is genetically engineered to produce beta-carotene, a precursor of Vitamin A, to combat Vitamin A deficiency in populations with limited access to diverse diets.

Q13. Which of the following Bt crops is being grown in India by the farmers?

1. Cotton
2. Brinjal
3. Soyabean
4. Maize

Answer: Cotton

Bt cotton is the only genetically modified crop that has been approved for commercial cultivation in India to control bollworm pests.

Q14. Consumption of which one of the following foods can prevent the kind of blindness associated with vitamin ‘A’ deficiency?

1. ‘Flavr Savr’ tomato
2. Canolla
3. Golden rice
4. Bt-Brinjal

Answer: Golden rice

Golden rice is genetically modified to contain beta-carotene, a precursor of vitamin A, which helps prevent blindness caused by vitamin A deficiency.

Q15. Tobacco plants resistant to a nematode have been developed by the introduction of DNA that produces (in the host cells):

1. both sense and anti-sense RNA
2. a particular hormone
3. an antifeedant
4. a toxic protein

Answer: both sense and anti-sense RNA

Tobacco plants resistant to nematodes were developed using RNA interference (RNAi) technology. This involves introducing DNA that produces both sense and anti-sense RNA, which form a double-stranded RNA to silence the nematode's essential genes.

Q16. The process of RNA interference has been used in the development of plants resistant to

1. nematodes
2. fungi
3. viruses
4. insects

Answer: nematodes

RNA interference (RNAi) is a biological process used to silence specific genes. It has been applied to develop plants resistant to nematodes by targeting and silencing essential genes in the nematodes, thereby preventing their infestation.

Q17. Silencing of mRNA has been used in producing transgenic plants resistant to:

1. bollworms
2. nematodes
3. white rusts
4. bacterial blights

Answer: nematodes

Silencing of mRNA through RNA interference (RNAi) has been used to develop transgenic plants resistant to nematodes, such as Meloidogyne incognita, by blocking the expression of essential genes in the nematode.

Q18. Bacillus thuringiensis forms protein crystals which contain insecticidal protein that

1. binds with epithelial cells of midgut of the insect pest ultimately killing it
2. is coded by several genes including the gene cry
3. is activated by acid pH of the foregut of the insect pest
4. does not kill the carrier bacterium which is itself resistant to this toxin

Answer: binds with epithelial cells of midgut of the insect pest ultimately killing it

Bacillus thuringiensis produces protein crystals containing insecticidal proteins that bind to the epithelial cells of the insect's midgut, causing cell lysis and death. This is a key mechanism of its action.

Q19. Some of the characteristics of Bt cotton are:

1. long fibre and resistance to aphids
2. medium yield, long fibre and resistance to beetle pests
3. high yield and production of toxic protein crystals which kill dipteran pests
4. long fibre and resistance to bollworms

Answer: long fibre and resistance to bollworms

Bt cotton is genetically modified to produce a toxic protein (Cry protein) that specifically targets and kills bollworms, a major pest. This is its primary characteristic.

Q20. What is true about Bt toxin?

1. Bt protein exists as active toxin in the Bacillus
2. The activated toxin enters the ovaries of the pest to sterilize it and thus prevents its multiplication.
3. The concerned Bacillus has antitoxins.
4. The inactive protoxin gets converted into active form in the insect gut.

Answer: The inactive protoxin gets converted into active form in the insect gut.

Bt toxin is produced as an inactive protoxin by Bacillus thuringiensis and becomes active in the alkaline environment of the insect gut, where it binds to gut epithelial cells and causes cell lysis.