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 31–40 of 179 questions
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q31. Match List-I with List-II regarding chromosome types:
Chromosome type
Centromere position
A. Metacentric
i. Centromere at the terminal end
B. Sub-metacentric
ii. Centromere in the middle, equal arms
C. Acrocentric
iii. Centromere close to the end
D. Telocentric
iv. Centromere slightly away from the middle
Explanation
A metacentric chromosome has its centromere in the middle, a sub-metacentric slightly away from the middle, an acrocentric close to one end and a telocentric at the terminal end. This gives A-ii, B-iv, C-iii, D-i.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q32. Consider the following statements about human chromosomes: I. The Y chromosome is smaller than the X chromosome. II. Telomeres protect the ends of chromosomes from deterioration. III. Kinetochores form at the centromere during cell division. IV. A normal human female karyotype is 46, XY. V. Histone proteins help package DNA into chromosomes. Which of the above statements is incorrect?
Explanation
In human genetics, a normal female karyotype is designated as forty-six, XX, while a male is forty-six, XY. The Y chromosome is physically smaller than the X. Telomeres provide essential protection at chromosomal ends, and kinetochores are necessary for spindle attachment. Histone proteins facilitate DNA packaging. Therefore, identifying a female as having an XY configuration is factually incorrect.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q33. What is the primary function of telomeres?
Explanation
Telomeres are repetitive nucleotide sequences located at the extreme ends of linear chromosomes. Their primary role is to protect the ends of the DNA from deterioration or fusion with neighboring chromosomes. Because DNA polymerase cannot fully replicate the very tips of chromosomes, telomeres act as a buffer, ensuring that essential genetic information is not lost during successive rounds of cellular division and replication.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q34. Which of the following chromosomal arrangements represents the karyotype of a normal human male?
Explanation
The karyotype of a normal human male consists of forty-six chromosomes in total. This includes twenty-two pairs of autosomes, which equals forty-four autosomes, and one pair of sex chromosomes consisting of one X and one Y chromosome. This chromosomal arrangement distinguishes males from females, who possess two X chromosomes alongside the forty-four autosomes. This genetic configuration is established at the moment of fertilization.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q35. Which of the following represents the odd one out regarding chromosome structural components?
Explanation
Centromeres, chromatids, and telomeres are all integral structural components of eukaryotic chromosomes found within the cell nucleus. In contrast, a plasmid is a small, circular, extra-chromosomal DNA molecule found primarily in bacteria. Plasmids replicate independently of the main bacterial chromosome and are not part of the standard structural anatomy of the linear chromosomes found in higher eukaryotic organisms like humans.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q36. The basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound around histone protein cores, is known as a:
Explanation
A nucleosome is the fundamental repeating subunit of chromatin in eukaryotic cells. It consists of approximately 147 base pairs of DNA wrapped twice around a core of eight histone proteins. This beads-on-a-string structure allows for the efficient compaction of long DNA molecules into the small space of the cell nucleus while still permitting access for essential processes like transcription and replication.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q37. A mutation that involves the substitution of a single base pair in the DNA sequence is known as a:
Explanation
A point mutation is a type of genetic alteration where a single nucleotide base is changed, inserted, or deleted from a DNA or RNA sequence. When one base is substituted for another, it can result in various outcomes, such as changing a single amino acid in a protein or having no effect at all. These mutations are the smallest scale of genetic variation that can occur.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q38. Given below are two statements, one labeled as Assertion (A) and the other as Reason (R): Assertion (A): Frameshift mutations generally have a more severe effect on protein function than point mutations. Reason (R): Frameshift mutations alter the entire reading frame of the mRNA downstream of the mutation site. Select the correct answer from the codes given below:
Explanation
Frameshift mutations occur when nucleotides are inserted or deleted in numbers not divisible by three. Because the genetic code is read in triplets, this shifts the entire reading frame for all subsequent codons. This usually results in a completely different and often non-functional protein. In contrast, a point mutation typically affects only one codon, making its impact generally less severe than a frameshift.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q39. Which of the following is an example of a physical mutagen?
Explanation
Mutagens are agents that increase the frequency of mutations in an organisms DNA. Physical mutagens include various forms of high-energy radiation. Ultraviolet radiation is a well-known physical mutagen that causes the formation of pyrimidine dimers, particularly thymine dimers, which distort the DNA structure. This contrasts with chemical mutagens like nitrous acid or mustard gas, which interact chemically with the nitrogenous bases.
RAS PrelimsScience and Technology · Genetics, Biotechnology and Nanotechnology
Q40. Consider the following statements regarding mutations: I. Germline mutations can be inherited by the offspring. II. Somatic mutations are passed down to future generations. III. Silent mutations do not change the amino acid sequence of the protein. Which of the above statement(s) is/are correct?
Explanation
Germline mutations occur in the reproductive cells and are passed on to offspring, making them heritable. Silent mutations are changes in the DNA sequence that do not alter the resulting amino acid sequence due to the redundancy of the genetic code. Somatic mutations, however, occur in non-reproductive body cells and are not inherited by future generations, affecting only the individual in whom they occur.
Answer key for these questions
Q
Correct answer
31
(a) A-ii, B-iv, C-iii, D-i
32
(b) IV only
33
(d) Maintenance of genomic stability during DNA replication
34
(b) 44 Autosomes + XY
35
(c) Plasmid
36
(d) Nucleosome
37
(c) Point mutation
38
(a) Both A and R are true and R is the correct explanation of A.
39
(a) Ultraviolet (UV) radiation
40
(c) I and III only
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.
