Q91. Why is a single recognition site for a given restriction enzyme preferred in a cloning vector?
Genetics, Biotechnology and Nanotechnology: RAS Prelims MCQs
179 RAS Prelims MCQs on genetics, biotechnology and nanotechnology cover DNA structure, chromosomes, recombinant DNA tools, plant tissue culture, biotech products and bioethics. Purines, base pairing, Chargaff’s rule, vectors, totipotency, Humulin, Feynman’s lecture, the Nagoya Protocol and biopiracy are asked as facts and sequences, with explanations that name the process behind each fact.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
Showing 91–100 of 179 questions
Q92. The primary purpose of gene cloning in biotechnology is to:
Explanation
The fundamental goal of gene cloning is to isolate a specific DNA sequence and produce many identical copies of it. This allows scientists to obtain enough material to study the genes structure, sequence, and function, or to use the cloned DNA for practical applications like gene therapy, the creation of transgenic organisms, or the industrial-scale production of valuable proteins like hormones.
Q93. Match List-I with List-II regarding genetically modified crops:
| GM Crop | Specific Trait |
|---|---|
| A. Bt Cotton | i. Delayed ripening |
| B. Golden Rice | ii. Insect resistance against bollworms |
| C. Flavr Savr Tomato | iii. Herbicide tolerance and higher yield |
| D. GM Mustard (DMH-11) | iv. Biofortified with Vitamin A precursor |
Explanation
Characteristics of Genetically Modified Crops A. Bt Cotton provides resistance against bollworms. B. Golden Rice is biofortified with Vitamin A precursors. C. Flavr Savr Tomato was engineered for delayed ripening. D. GM Mustard DMH-eleven exhibits herbicide tolerance. These traits illustrate how biotechnology can enhance agricultural productivity, nutritional value, and shelf life of food through targeted genetic modifications across different biological species.
Q94. Consider the following statements regarding Bt cotton:
I. It contains cry genes isolated from the bacterium Bacillus thuringiensis.
II. The Bt toxin protein is produced in the plant as an inactive protoxin.
III. The toxin is activated by the alkaline pH of the insect gut.
IV. It is currently approved for commercial cultivation in India.
Which of the above statement(s) is/are correct?
I. It contains cry genes isolated from the bacterium Bacillus thuringiensis.
II. The Bt toxin protein is produced in the plant as an inactive protoxin.
III. The toxin is activated by the alkaline pH of the insect gut.
IV. It is currently approved for commercial cultivation in India.
Which of the above statement(s) is/are correct?
Explanation
Bt cotton is a transgenic variety containing cry genes from Bacillus thuringiensis. The plant produces the Bt toxin in an inactive protoxin form, which is harmless to the plant and humans. However, when an insect consumes the plant tissue, the alkaline pH of its gut activates the toxin, leading to pore formation and death. This crop is currently commercially cultivated in India.
Q95. Golden Rice is a genetically modified crop engineered to produce high levels of:
Explanation
Golden Rice is a variety of rice produced through genetic engineering to biosynthesize beta-carotene, which the human body converts into Vitamin A. This crop was developed as a humanitarian tool to combat Vitamin A deficiency, a major cause of blindness and health issues in developing countries where rice is a staple food. The name comes from the characteristic yellow-orange color of grains.
Q96. The toxic protein produced by Bacillus thuringiensis does not kill the bacterium itself because:
Explanation
Bacillus thuringiensis does not suffer from its own toxin because the protein is synthesized and stored as an inactive, crystalline protoxin. The toxin only becomes active and lethal when it is ingested by a susceptible insect and exposed to the specific alkaline environment of the insects midgut. This natural safety mechanism ensures that the bacterium can produce the protein without causing self-destruction.
Q97. Which of the following is an environmental concern associated with the cultivation of Genetically Modified (GM) crops?
Explanation
A significant environmental concern regarding GM crops is the possibility of gene flow, where pollen from the modified crop fertilizes related wild plants or weeds. If the transgene is transferred, it could create superweeds that are difficult to control. This potential for unintended ecological consequences requires careful monitoring and regulation of the release and cultivation of genetically modified organisms in the environment.
Q98. Identify the incorrect statement regarding transgenic animals.
Explanation
Transgenic animals are specifically designed and extensively used for chemical and drug safety testing. They can be engineered to be more sensitive to toxic substances, allowing for faster and more accurate results than traditional animal models. Other statements are correct: they are used for vaccine safety, studying human diseases like Alzheimers, and the first transgenic cow, Rosie, produced human protein-enriched milk.
Q99. The term biofortification in agriculture refers to:
Explanation
Biofortification is the process of increasing the nutritional quality of food crops through agronomic practices, conventional plant breeding, or modern biotechnology. Unlike traditional fortification, which adds nutrients during food processing, biofortification aims to make the plants themselves richer in essential vitamins and minerals while they are growing, providing a sustainable way to improve public health in nutrient-deficient populations worldwide.
Q100. What triggers the activation of the Bt toxin in the gut of the target insect?
Explanation
The activation of the Bt toxin is highly specific to the environment of the target insects gut. The inactive protoxin crystals ingested by the insect are solubilized and proteolytically cleaved into an active form only when they encounter the alkaline pH conditions found in the midgut. This active toxin then binds to specific receptors on the gut lining, causing cell lysis and death.Answer key for these questions
| Q | Correct answer |
|---|---|
| 91 | (c) Prevention of vector fragmentation during cloning steps |
| 92 | (a) Create multiple exact copies of a specific DNA segment |
| 93 | (a) A-ii, B-iv, C-i, D-iii |
| 94 | (d) I, II, III and IV |
| 95 | (b) Beta-carotene |
| 96 | (c) The toxin exists as an inactive protoxin crystal inside the bacterium. |
| 97 | (b) The potential for gene flow to wild relatives, creating superweeds |
| 98 | (d) Transgenic animals cannot be used for chemical safety testing. |
| 99 | (a) Breeding crops to increase their nutritional value. |
| 100 | (c) Alkaline pH |
Key facts from Genetics, Biotechnology and Nanotechnology
- Adenine is a purine and pairs with thymine through two hydrogen bonds; the distance between consecutive base pairs in B-DNA is 0.34 nm.
- Chargaff’s rule says that adenine equals thymine and guanine equals cytosine; the human karyotype has 22 pairs of autosomes.
- Telomeres maintain genomic stability during DNA replication; heterochromatin is the condensed, inactive region.
- Humulin was the first commercially produced genetically engineered human hormone.
- Totipotency is the capacity of a single plant cell to regenerate a whole plant; the meristem is used to get virus-free plants.
- Richard Feynman’s 1959 lecture began nanotechnology; the Nagoya Protocol governs benefit sharing; the US patent on turmeric was revoked after a biopiracy battle.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Genetics, Biotechnology and Nanotechnology?
This page has 179 practice MCQs on Genetics, Biotechnology and Nanotechnology (Science and Technology). Each has the correct answer, and most have an explanation.
How many hydrogen bonds pair adenine with thymine?
Two. Adenine pairs with thymine by two hydrogen bonds, and guanine pairs with cytosine by three, which is why DNA rich in G and C is more stable.
What is totipotency?
The capacity of a single plant cell to regenerate into an entire plant. It is the basis of plant tissue culture, in which cells grown on a nutrient medium form a callus and then shoots and roots.
Which protocol deals with sharing the benefits of genetic resources?
The Nagoya Protocol to the Convention on Biological Diversity. It ensures that the benefits from using genetic resources are shared fairly with the countries and communities that provide them.