Q111. CRISPR-Cas9 is a revolutionary technology primarily used for:
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 111–120 of 179 questions
Q112. Given below are two statements, one labeled as
Assertion (A) and the other as Reason (R):
Assertion (A): CRISPR-Cas9 was originally discovered as an adaptive immune system in bacteria.
Reason (R): Bacteria use CRISPR-Cas9 to remember and cut the DNA of invading viruses (bacteriophages).
Select the correct answer from the codes given below:
Assertion (A) and the other as Reason (R):
Assertion (A): CRISPR-Cas9 was originally discovered as an adaptive immune system in bacteria.
Reason (R): Bacteria use CRISPR-Cas9 to remember and cut the DNA of invading viruses (bacteriophages).
Select the correct answer from the codes given below:
Explanation
CRISPR-Cas9 was not originally an artificial invention but was discovered as a natural adaptive immune system in bacteria and archaea. Bacteria use CRISPR sequences to store fragments of DNA from viruses that have previously attacked them. If the same virus invades again, the Cas9 enzyme uses the stored RNA memory to recognize and cut the viral DNA, effectively neutralizing the threat.
Q113. Who among the following were awarded the Nobel Prize in Chemistry in 2020 for the development of the CRISPR-Cas9 method for genome editing?
Explanation
Emmanuelle Charpentier and Jennifer Doudna were awarded the Nobel Prize in Chemistry in 2020 for their pioneering work in developing the CRISPR-Cas9 gene-editing method. They showed that the bacterial defense system could be repurposed into a versatile and programmable tool for editing any DNA sequence in any organism. Their discovery has had an immense impact on life sciences and medicine.
Q114. In the acronym CRISPR, what does the R stand for?
Explanation
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. The R stands for Repeats, referring to the identical, short sequences of DNA that are repeated at regular intervals within the bacterial genome. These repeats are separated by spacer DNA derived from past viral invaders. This structural organization is the hallmark of this microbial immune system and provides the basis for targeting.
Q115. A major potential application of CRISPR-Cas9 technology in human medicine is:
Explanation
The most promising medical application of CRISPR-Cas9 technology is the potential to treat and even cure inherited genetic disorders by directly correcting the underlying mutations. By targeting the defective gene in a patients cells and replacing it with a healthy sequence, CRISPR could offer permanent solutions for conditions like sickle cell anemia and cystic fibrosis, which currently have limited treatment options.
Q116. What happens immediately after Cas9 makes a double-strand break in the target DNA?
Explanation
Once the Cas9 enzyme creates a double-strand break in the target DNA, the cells internal repair machinery is immediately activated to fix the damage. Scientists exploit these natural processes to edit the genome. One pathway often introduces small errors, effectively disabling the gene, while another pathway can use a provided DNA template to precisely insert a new sequence at the break site.
Q117. Off-target effects in CRISPR technology refer to:
Explanation
A major challenge in CRISPR technology is the occurrence of off-target effects, which happen when the Cas9 enzyme binds to and cuts DNA at locations other than the intended target. This occurs because the guide RNA may accidentally recognize sequences that are very similar to the target site. These unintended cuts can lead to harmful mutations elsewhere in the genome, raising safety concerns.
Q118. Gene drive is a controversial application of CRISPR that allows:
Explanation
A gene drive is a sophisticated application of CRISPR that ensures a specific genetic modification is passed on to nearly all offspring, bypassing traditional inheritance. This allows the modification to spread rapidly through an entire wild population. While it could be used to eliminate disease-carrying mosquitoes, it raises significant ethical and ecological concerns due to its potential to permanently alter entire ecosystems.
Q119. Stem cells possess two fundamental properties: self-renewal and the ability to differentiate into specialized cell types. Cells that can develop into a complete organism are termed:
Explanation
Totipotent stem cells possess the highest level of differentiation potential. A single totipotent cell, such as a zygote or cells from the very first few divisions, has the extraordinary ability to differentiate into any cell type in the body as well as the extra-embryonic tissues like the placenta. Consequently, these cells have the capacity to develop into a complete, independent organism.
Q120. Consider the following statements regarding stem cells:
Statement I: Adult stem cells are generally multipotent, meaning they can only differentiate into a limited number of cell types related to their tissue of origin.
Statement II: Embryonic stem cells, derived from the inner cell mass of a blastocyst, are pluripotent and can form any cell type in the adult body.
Which of the following represents the correct option?
Statement I: Adult stem cells are generally multipotent, meaning they can only differentiate into a limited number of cell types related to their tissue of origin.
Statement II: Embryonic stem cells, derived from the inner cell mass of a blastocyst, are pluripotent and can form any cell type in the adult body.
Which of the following represents the correct option?
Explanation
Adult stem cells are multipotent, meaning they are typically restricted to becoming cell types within their specific tissue of origin, such as blood stem cells only making blood cells. In contrast, embryonic stem cells are pluripotent; they are derived from the blastocyst and have the broader capability to differentiate into any of the more than 200 specialized cell types in the body.Answer key for these questions
| Q | Correct answer |
|---|---|
| 111 | (c) Targeted and precise gene editing |
| 112 | (a) Both A and R are true and R is the correct explanation of A. |
| 113 | (a) Emmanuelle Charpentier and Jennifer Doudna |
| 114 | (d) Repeats |
| 115 | (b) Curing genetic diseases by correcting mutations |
| 116 | (a) The cell’s natural DNA repair mechanisms try to fix the break. |
| 117 | (c) Cas9 cutting DNA at unintended sites with similar sequences |
| 118 | (d) Promoting universal inheritance of a genetic alteration |
| 119 | (b) Totipotent |
| 120 | (a) Both Statement I and Statement II are correct. |
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.