Q681. The ampicillin resistance gene in plasmid pBR322 acts as a:
Science and Technology: RAS Prelims MCQs
1113 RAS Prelims practice MCQs on science and technology are on this page, in 6 chapters. They cover the basics of everyday science, computers and information technology, defence and space technology in India, genetics, biotechnology and nanotechnology, science and technology policies and government programmes, and recent advances with Indian contributors and indigenisation. Each question has an answer and an explanation.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q682. The phenomenon where the insertion of a foreign gene within the coding sequence of an enzyme gene leads to the loss of that enzymes activity is known as:
Explanation
Insertional inactivation is a technique used to identify recombinant clones. When a foreign DNA fragment is inserted into the coding sequence of a reporter gene, it disrupts the genes function. For example, if the lacZ gene is inactivated, the bacteria will no longer be able to produce the enzyme beta-galactosidase, resulting in white colonies instead of blue on specific media, signaling a successful insertion.
Q683. Which of the following vectors is most commonly used to transfer genes into dicot plants?
Explanation
The Ti plasmid of the soil bacterium Agrobacterium tumefaciens is the most widely used vector for genetic engineering in dicotyledonous plants. In nature, this bacterium transfers a segment of its Ti plasmid into the plant genome. Scientists have disarmed this plasmid by removing the disease-causing genes and replacing them with genes of interest, effectively turning the bacterium into a natural gene delivery system.
Q684. The process of introducing recombinant vectors into animal cells is often achieved through:
Explanation
Introducing recombinant DNA into animal cells requires different methods than bacterial transformation. Microinjection involves using a very fine glass needle to inject DNA directly into the nucleus of a cell or embryo. Electroporation uses brief pulses of high-voltage electricity to create temporary pores in the cell membrane, allowing the DNA to enter. Other methods include using viral vectors or lipid-based carriers.
Q685. Identify the incorrect statement regarding cloning vectors.
Explanation
Bacteriophages are viruses that infect bacteria, and they are extensively used as cloning vectors because they can naturally inject their DNA into host cells and accommodate larger DNA inserts than standard plasmids. Other statements are correct: high copy numbers increase yield; YACs and BACs are specialized for very large genomic fragments; and expression vectors are designed with regulatory sequences needed to produce proteins.
Q686. Why is a single recognition site for a given restriction enzyme preferred in a cloning vector?
Explanation
A cloning vector should ideally have only one recognition site for a particular restriction enzyme. If multiple sites were present, the enzyme would cut the vector into several fragments, making it difficult to reassemble and significantly complicating the process of inserting the foreign gene. Having a single site ensures that the circular vector is linearized at a specific point, allowing foreign DNA integration.
Q687. 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.
Q688. 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.
Q689. 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.
Q690. 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.Answer key for these questions
| Q | Correct answer |
|---|---|
| 681 | (a) Selectable marker |
| 682 | (c) Insertional inactivation |
| 683 | (b) Ti plasmid of Agrobacterium tumefaciens |
| 684 | (d) Electroporation or microinjection |
| 685 | (a) Bacteriophages cannot be used as cloning vectors. |
| 686 | (c) Prevention of vector fragmentation during cloning steps |
| 687 | (a) Create multiple exact copies of a specific DNA segment |
| 688 | (a) A-ii, B-iv, C-i, D-iii |
| 689 | (d) I, II, III and IV |
| 690 | (b) Beta-carotene |
Key facts from Science and Technology
- The RPSC paper is General Knowledge and General Science, so science questions come with a strong dose of applied and recent topics.
- Everyday science questions test the laws and terms of physics, chemistry and biology through examples.
- Defence and space questions pair a missile, satellite or mission with its year and organisation.
- Policy questions ask for the year, the body and the aim of schemes like STIP, the National Quantum Mission and BioE3.
- Health, environment and agriculture are on a separate page, with their own chapters.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Science and Technology?
This page has 1113 practice MCQs on Science and Technology. Each has the correct answer, and most have an explanation.
Which chapters does the science and technology set cover?
Six chapters: basics of everyday science; computers, information and communication technology; defence and space technology in India; genetics, biotechnology and nanotechnology; science and technology policies and government programmes; and recent advances, Indian contributors and indigenisation.
Is science and technology part of the RAS Prelims syllabus?
Yes. The RPSC paper is called General Knowledge and General Science, and its syllabus lists science and technology topics along with environment, health, agriculture and government programmes, so questions can come from any of these areas.
How should I prepare science for RAS Prelims?
Revise the concepts by examples, then learn the missions, schemes and scientists with their year and organisation. Attempt each chapter, read the explanations and keep a list of the facts you missed.