Q601. Which among the following is not a function of DNA?
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.
Showing 601–610 of 1113 questions
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Q602. The distance between two consecutive base pairs in a standard B-DNA double helix is approximately:
Explanation
In the standard B-DNA double helix model, the vertical distance between two adjacent nitrogenous base pairs is approximately 0.34 nanometers. This precise spacing contributes to the overall stability of the helix through base-stacking interactions. Given that one full helical turn covers 3.4 nanometers and contains ten base pairs, the calculated distance between individual steps remains remarkably consistent.
Q603. Which of the following rules states that the amount of adenine equals the amount of thymine, and the amount of guanine equals cytosine in DNA?
Explanation
Erwin Chargaff formulated the rule stating that in the DNA of any given species, the ratio of adenine to thymine is equal, as is the ratio of guanine to cytosine. This observation provided critical evidence for the base-pairing mechanism in the double helix model. These stoichiometric equalities ensure that the total purine content always equals the total pyrimidine content.
Q604. The process by which DNA makes a copy of itself is known as:
Explanation
Replication is the biological process by which a cell creates an identical duplicate of its entire DNA molecule. This occurs during the S-phase of the cell cycle to ensure that both resulting daughter cells receive a complete set of genetic instructions. The process is semi-conservative, meaning each new double helix consists of one original strand and one newly synthesized strand.
Q605. A gene is best defined as:
Explanation
A gene represents the basic physical and functional unit of heredity. Structurally, it is a specific sequence of nucleotides located at a particular position on a chromosome. These segments contain the coded instructions required to synthesize functional products, such as polypeptide chains or various types of RNA molecules, which ultimately determine the traits and characteristics of a living organism.
Q606. The specific physical location of a gene on a chromosome is called its:
Explanation
The term locus refers to the fixed, specific physical position that a gene or a particular DNA sequence occupies on a chromosome. Mapping these locations is essential for understanding genetic linkage and inheritance patterns. In diploid organisms, homologous chromosomes contain the same genes at identical loci, although the specific alleles present at those positions may differ between the two.
Q607. 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.
Q608. 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.
Q609. 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.
Q610. 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.Answer key for these questions
| Q | Correct answer |
|---|---|
| 601 | (b) Direct synthesis of lipids in the cytoplasm |
| 602 | (a) 0.34 nm |
| 603 | (a) Chargaffs Rule |
| 604 | (a) Replication |
| 605 | (d) A specific DNA segment encoding a functional protein or RNA |
| 606 | (b) Locus |
| 607 | (a) B, A, C, D |
| 608 | (a) A-iv, B-iii, C-i, D-ii |
| 609 | (a) DNA to RNA to Protein |
| 610 | (b) Alleles |
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.