Q151. To produce virus-free plants from a virus-infected plant via tissue culture, which specific part of the plant is used as an explant?
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 151–160 of 179 questions
Q152. The fusion of isolated protoplasts from two different plant species to create a hybrid (like the Pomato) is an example of:
Explanation
Somatic hybridization is a technique where the cell walls of two different plant species are removed to create protoplasts, which are then fused together to form a hybrid cell. This allows for the combination of traits from species that cannot be crossed through sexual reproduction. A famous example is the Pomato, a hybrid produced by fusing protoplasts from potato and tomato.
Q153. What is the role of polyethylene glycol (PEG) in agricultural biotechnology?
Explanation
Polyethylene glycol is a chemical agent used in agricultural biotechnology to facilitate the fusion of plant protoplasts during somatic hybridization. Because protoplasts are negatively charged, they naturally repel each other. Adding PEG acts as a molecular bridge that reduces this repulsion and alters the cell membrane properties, allowing the protoplasts from two different species to come into close contact and merge.
Q154. Which of the following best describes the principle of RNA interference (RNAi)?
Explanation
RNA interference is a natural biological process where double-stranded RNA molecules inhibit gene expression or translation. When dsRNA enters a cell, it is processed into short fragments that guide a protein complex to a specific messenger RNA molecule. The complex then binds to and cleaves the mRNA, preventing it from being translated into a protein. This results in specific gene silencing.
Q155. Match List-I with List-II regarding nanomaterials:
| Nanomaterial | Characteristic |
|---|---|
| A. Graphene | i. Hollow spherical cages of 60 carbon atoms |
| B. Carbon Nanotubes (CNTs) | ii. Semiconductor nanocrystals with unique optical properties |
| C. Quantum dots | iii. Cylindrical carbon structures with exceptional tensile strength |
| D. Fullerenes (Buckyballs) | iv. A single layer of carbon atoms arranged in a 2D hexagonal lattice |
Explanation
Nanomaterials come in various structural forms. Graphene is a single, two-dimensional layer of carbon atoms in a hexagonal lattice. Carbon Nanotubes are cylindrical structures with immense strength. Quantum dots are tiny semiconductor crystals with unique optical properties, such as size-dependent light emission. Fullerenes are hollow spherical molecules composed of sixty carbon atoms arranged in a pattern resembling a soccer ball.
Q156. Consider the following statements about nanotechnology:
I. Nanomaterials exhibit significantly different physical and chemical properties compared to their bulk counterparts.
II. An increase in the surface area-to-volume ratio at the nanoscale often increases chemical reactivity.
III. Richard Feynman is widely considered a founding father of nanotechnology concepts.
Which of the above statement(s) is/are correct?
I. Nanomaterials exhibit significantly different physical and chemical properties compared to their bulk counterparts.
II. An increase in the surface area-to-volume ratio at the nanoscale often increases chemical reactivity.
III. Richard Feynman is widely considered a founding father of nanotechnology concepts.
Which of the above statement(s) is/are correct?
Explanation
Nanomaterials possess distinct properties compared to bulk materials due to quantum effects and a drastically increased surface area-to-volume ratio, which often significantly enhances their chemical reactivity. The theoretical foundation for the field was famously laid by physicist Richard Feynman in his 1959 lecture. These three points form the fundamental basis for understanding why nanotechnology is so versatile across diverse disciplines.
Q157. A nanometer is equal to:
Explanation
A nanometer is a unit of length in the metric system equal to one-billionth of a meter. In scientific notation, this is expressed as 10 to the power of negative nine meters. To provide perspective, a single human hair is approximately 80,000 to 100,000 nanometers wide. This extreme miniaturization is what allows nanotechnology to interact with biological molecules on their own scale.
Q158. Which phenomenon explains why quantum dots emit light of varying colors depending on their size?
Explanation
The unique ability of quantum dots to emit light of specific colors based on their size is a result of a phenomenon called quantum confinement. When a semiconductor crystal becomes smaller than a certain threshold, its electronic properties change. Smaller dots have a larger energy gap and emit shorter wavelengths, while larger dots have a smaller gap and emit longer wavelengths of light.
Q159. Which of the following approaches involves assembling atoms or molecules to build nanoscale structures?
Explanation
In nanotechnology, the bottom-up approach refers to the process of building complex nanoscale structures by assembling them atom-by-atom or molecule-by-molecule. This is often achieved through chemical synthesis or self-assembly, where molecules naturally organize themselves into stable structures due to their inherent chemical properties.
Q160. Identify the incorrect statement regarding nanomaterials.
Explanation
Carbon nanotubes are actually exceptional conductors of electricity, far superior to wood and even better than some metals like copper. They have the ability to carry high electrical currents with very little resistance. Other statements are correct: gold nanoparticles can appear red or purple; breaking down bulk materials increases their relative surface area; and graphene is famously the thinnest known material.Answer key for these questions
| Q | Correct answer |
|---|---|
| 151 | (d) Meristem (apical or axillary) |
| 152 | (a) Somatic hybridization |
| 153 | (c) It induces the fusion of plant protoplasts. |
| 154 | (a) Gene silencing via complementary double- stranded RNA |
| 155 | (a) A-iv, B-iii, C-ii, D-i |
| 156 | (d) I, II and III |
| 157 | (b) 10-9 meters |
| 158 | (c) Quantum confinement |
| 159 | (a) Bottom-up approach |
| 160 | (d) Carbon nanotubes are poorer conductors of electricity than wood. |
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.