Q51. Identify the correct pair regarding human genetic disorders:
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 51–60 of 179 questions
Q52. Individuals heterozygous for the sickle cell trait have a survival advantage against which infectious disease?
Explanation
Individuals who are heterozygous for the sickle cell allele possess a significant survival advantage in regions where malaria is endemic. The presence of the sickle hemoglobin makes their red blood cells less hospitable to the Plasmodium parasite. This phenomenon, known as heterozygote advantage, explains why the sickle cell gene remains prevalent in certain populations despite the severity of the homozygous disease.
Q53. The failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to conditions like Down syndrome, is called:
Explanation
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division, specifically during meiosis I or II. This error leads to gametes with an abnormal number of chromosomes, either too many or too few. When such a gamete participates in fertilization, it results in aneuploid conditions such as Down syndrome (trisomy) or Turners syndrome (monosomy).
Q54. A woman who is a carrier for haemophilia marries a normal man. What is the probability that their son will have haemophilia?
Explanation
A carrier woman has one normal X chromosome and one X chromosome with the haemophilia allele. A normal man has XY. Their sons receive a Y from the father and either the normal X or the Xh from the mother. Therefore, there is a fifty percent chance that a son will inherit the Xh chromosome and have haemophilia. The daughters would be either normal or carriers.
Q55. Genetic engineering primarily involves the manipulation of:
Explanation
Genetic engineering is a field of biotechnology that primarily involves the direct manipulation of an organisms deoxyribonucleic acid (DNA). By using molecular tools to cut, copy, and move specific segments of DNA, scientists can alter the genetic makeup of cells and organisms. This allows for the introduction of new traits, the removal of undesirable ones, or the mass production of essential biological products.
Q56. Consider the following statements about recombinant DNA (rDNA) technology:
I. It involves cutting DNA from two different sources and joining them together.
II. A host organism, typically a bacterium, is used to multiply the recombinant DNA.
III. It completely avoids the use of vectors.
IV. Stanley Cohen and Herbert Boyer produced the first recombinant DNA molecule.
Which of the above statement(s) is/are correct?
I. It involves cutting DNA from two different sources and joining them together.
II. A host organism, typically a bacterium, is used to multiply the recombinant DNA.
III. It completely avoids the use of vectors.
IV. Stanley Cohen and Herbert Boyer produced the first recombinant DNA molecule.
Which of the above statement(s) is/are correct?
Explanation
Recombinant DNA technology involves combining DNA fragments from different sources to create a new genetic sequence. A host organism, such as E. coli, is essential for cloning and multiplying this DNA. The first successful recombinant DNA was created by Cohen and Boyer.
Q57. Consider the following statements regarding genetic engineering:
Statement I: Genetic engineering allows for the transfer of genes across different biological species.
Statement II: Natural sexual reproduction strictly restricts gene transfer to members of the same or closely related species.
Which of the following represents the correct option?
Statement I: Genetic engineering allows for the transfer of genes across different biological species.
Statement II: Natural sexual reproduction strictly restricts gene transfer to members of the same or closely related species.
Which of the following represents the correct option?
Explanation
Genetic engineering breaks biological barriers by allowing the transfer of specific genes between entirely different species, such as moving a bacterial gene into a plant. In contrast, natural sexual reproduction is generally restricted by biological compatibility, occurring only between members of the same species or very closely related ones. This fundamental difference enables biotechnology to create organisms with traits that could never arise through traditional breeding.
Q58. The first recombinant DNA molecule was created by linking an antibiotic resistance gene to a native plasmid of which bacterium?
Explanation
The first recombinant DNA molecule was constructed in 1972 by Stanley Cohen and Herbert Boyer. They successfully linked a gene encoding antibiotic resistance to a native plasmid of the bacterium Salmonella typhimurium. This pioneering experiment demonstrated that genetic material could be manipulated and functionalized in a foreign host, laying the foundation for the modern biotechnology industry.
Q59. In recombinant DNA technology, the term transformation refers to:
Explanation
In the context of recombinant DNA technology, transformation refers to the process by which a host cell, typically a bacterium, takes up foreign DNA from its environment. This is a crucial step in gene cloning, as it allows the recombinant vector to enter the cell where it can replicate and express the inserted gene. Various methods, such as heat shock, are used to facilitate this uptake.
Q60. Which of the following best describes a chimeric DNA?
Explanation
Chimeric DNA, often used synonymously with recombinant DNA, is a single DNA molecule that has been constructed in a laboratory using genetic material from two or more different biological sources or species. The name is derived from the Chimera of Greek mythology, a creature composed of parts from different animals. This molecular hybrid allows for the expression of specific foreign traits within a host organism.Answer key for these questions
| Q | Correct answer |
|---|---|
| 51 | (c) Klinefelters syndrome - 47, XXY |
| 52 | (b) Malaria |
| 53 | (c) Nondisjunction |
| 54 | (d) 50% |
| 55 | (c) Deoxyribonucleic acid (DNA) |
| 56 | (b) I, II and IV |
| 57 | (a) Both Statement I and Statement II are correct. |
| 58 | (a) Salmonella typhimurium |
| 59 | (b) The introduction of recombinant DNA into a host cell. |
| 60 | (d) Recombinant DNA formed from material of different species |
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.