Q11. The specific physical location of a gene on a chromosome is called its:
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 11–20 of 179 questions
Q12. Consider the following steps of gene expression:
A. mRNA leaves the nucleus
B. RNA polymerase transcribes DNA into mRNA
C. Ribosome translates mRNA into a polypeptide chain
D. Protein folding and modification
Which of the following represents the correct sequence?
A. mRNA leaves the nucleus
B. RNA polymerase transcribes DNA into mRNA
C. Ribosome translates mRNA into a polypeptide chain
D. Protein folding and modification
Which of the following represents the correct sequence?
Explanation
Gene expression begins with transcription, where RNA polymerase creates a messenger RNA transcript from the DNA template. This mRNA then exits the nucleus to reach the cytoplasm. Next, ribosomes translate the mRNA sequence into a polypeptide chain by assembling amino acids. Finally, the resulting chain undergoes specific folding and post-translational modifications to become a functional protein with a defined structure.
Q13. Match List-I with List-II regarding gene components:
| Gene component | Description |
|---|---|
| A. Promoter | i. Non-coding region of a gene |
| B. Exon | ii. Region marking the end of transcription |
| C. Intron | iii. Coding region of a gene |
| D. Terminator | iv. Binding site for RNA polymerase |
Explanation
A gene contains several distinct regions that regulate and encode information. The promoter acts as the initial binding site for RNA polymerase to start transcription. Exons are the coding sequences that remain in the final messenger RNA, while introns are non-coding regions removed during splicing. The terminator sequence signals the end of the transcription process to the molecular machinery.
Q14. The Central Dogma of molecular biology explains the flow of genetic information as:
Explanation
The Central Dogma of molecular biology describes the directional flow of genetic information within biological systems. Information stored in the DNA is first transcribed into messenger RNA molecules. Subsequently, this RNA serves as a template for translation by ribosomes, which synthesize specific proteins. This fundamental framework explains how the genetic code is converted into functional biological molecules and traits.
Q15. The variations of a particular gene are known as:
Explanation
Alleles are alternative forms of the same gene that arise by mutation and are found at the same place on a chromosome. They account for the diversity in inherited characteristics among individuals of the same species. For any given trait, an organism may inherit identical alleles, known as homozygous, or different alleles, which is referred to as a heterozygous condition.
Q16. Which of the following best describes an operon in bacterial gene expression?
Explanation
An operon is a functional unit of genomic DNA found primarily in prokaryotes. It consists of a cluster of related genes under the control of a single promoter and regulatory sequences. This arrangement allows the cell to efficiently coordinate the expression of multiple proteins required for a specific metabolic pathway, ensuring they are produced simultaneously in response to environmental stimuli.
Q17. Identify the correct pair:
Explanation
Homozygous refers to a genetic condition where an individual inherits two identical versions of a particular gene from both parents. This contrasts with the heterozygous state, where the two alleles at a specific locus are different. Genotype represents the internal genetic makeup, while phenotype describes the observable physical traits. Accurate terminology is essential for predicting inheritance patterns in classical Mendelian genetics.
Q18. Which cellular organelle is directly involved in the translation phase of gene expression?
Explanation
Ribosomes are the cellular organelles responsible for the translation phase of gene expression. They serve as the site where messenger RNA is read and converted into a specific sequence of amino acids to form a protein. These structures can be found floating freely in the cytoplasm or attached to the rough endoplasmic reticulum, facilitating the synthesis of essential biological molecules for the cell.
Q19. Mendels Law of Segregation states that:
Explanation
Mendels Law of Segregation states that during the formation of gametes, the two alleles for a heritable character separate from each other. Consequently, each gamete carries only one allele for every gene. The original paired condition is restored during fertilization when two gametes unite. This fundamental principle ensures that offspring receive one genetic contribution from each parent for every trait.
Q20. What is the phenotypic ratio in the F2 generation of a standard Mendelian monohybrid cross?
Explanation
In a standard Mendelian monohybrid cross, the F2 generation typically displays a phenotypic ratio of 3:1. This occurs when two heterozygous F1 individuals are crossed. Three-quarters of the offspring will exhibit the dominant trait, while one-quarter will show the recessive trait. This ratio reflects the underlying genotypic distribution of one homozygous dominant, two heterozygous, and one homozygous recessive individual.Answer key for these questions
| Q | Correct answer |
|---|---|
| 11 | (b) Locus |
| 12 | (a) B, A, C, D |
| 13 | (a) A-iv, B-iii, C-i, D-ii |
| 14 | (a) DNA to RNA to Protein |
| 15 | (b) Alleles |
| 16 | (b) Group of genes transcribed together from a single promoter |
| 17 | (c) Homozygous - Two identical alleles at a locus |
| 18 | (d) Ribosome |
| 19 | (c) Alleles separate into gametes and unite at fertilization |
| 20 | (c) 3:1 |
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.