Genetic Engineering and Biotechnology

Total Questions: 49

1. 'Microsatellite DNA' is used in the case of which one of the following? [I.A.S. (Pre) 2023]

(a) Studying the evolutionary relationships among various species of fauna
(b) Stimulating 'stem cells' to transform into diverse functional tissues
(c) Stimulating 'stem cells' to transform into diverse functional tissues
(d) Assessing the efficacy of drugs by conducting series of drug trials in a population

Correct Answer: (a) Studying the evolutionary relationships among various species of fauna

Solution:Microsatellite, as related to genomics, refers to a short segment of DNA, usually one to six or more base pairs in length, that is repeated multiple times in succession at a particular genomic location. These DNA sequences are typically non-coding. The number of repeated segments within a microsatellite sequence often varies among people, which makes them useful as polymorphic markers for studying inheritance patterns in families or for studying the evolutionary relationships among various species of fauna. They are widely used for DNA profiling in cancer diagnosis, in kinship analysis (especially paternity testing) and in forensic identification. They are also used in genetic linkage analysis to locate a gene or a mutation responsible for a given trait or disease. Microsatellites are also used in population genetics to measure levels of relatedness between subspecies, groups and individuals.

2. With reference to the recent developments in science, which one of the following statements is not correct? [I.A.S. (Pre) 2019]

(a) Functional chromosomes can be created by joining segments of DNA taken from cells of different species.
(b) Pieces of artificial functional DNA can be created in laboratories.
(c) A piece of DNA taken from an animal cell can be made to replicate outside a living cell in a laboratory.
(d) Cells taken from plants and animals can be made to undergo cell division in laboratory petri dishes.

Correct Answer: (a) Functional chromosomes can be created by joining segments of DNA taken from cells of different species.

Solution:Among the given statements, statement of option (a) is not correct, because functional chromosomes cannot be created by joining segments of DNA taken from cells of different species (through recombinant DNA technique only functional DNA can be created). Other three statements are correct, Statement of option (b) in context of artificial DNA synthesis, statement of option (c) in context of cloning and statement of option (d) in context of tissue culture are correct.

3. With reference to recent developments regarding ‘Recombinant Vector Vaccines,’ consider the following statements: [I.A.S. (Pre) 2021]

Genetic engineering is applied in the development of these vaccines.
Bacteria and viruses are used as vectors.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer: (c) Both 1 and 2

Solution:Live recombinant vector vaccines are made of a livel attenuated viral or bacterial strain used as a vector to carry the gene or genes encoding the desired vaccine antigens. In these vaccines live viral or bacterial vector is genetically engineered to express a variety of exogenous antigens in the cytoplasm of targeted T cells. Live recombinant vector vaccines have a number of attractive features, including the ability to stimulate both humoral and cell-mediated immunity. Recombinant vector vaccines (platform-based vaccines) act like a natural infection, so they're especially good at teaching the immune system how to fight germs.

4. Recombinant DNA Technology (Genetic Engineering) allows genes to be transferred - [I.A.S. (Pre) 2013]

1. Across different species of plants.
2. From animals to plants.
3. From microorganisms to higher organisms.

Select the correct answer using the codes given below:

(a) Only 1
(b) 2 and 3
(c) 1 and 3
(d) All of these

Correct Answer: (d) All of these

Solution:Recombinant DNA Technology is used to cut a known DNA sequence from one organism and introduce it into another, altering the genotype of the recipient. Foreign DNA sequences can be introduced into bacteria, yeast, viruses, plants, and animal cells. This technology allows gene sequences to be transferred between non-related species.

5. Steps of Recombinant DNA technology are given below: [R.A.S./R.T.S. (Pre) (Re. Exam) 2013]

A. Identification and isolation of the genetic material.
B. Fragmentation of DNA.
C. Obtaining the foreign gene product.
D. Downstream processing.
E. Ligation of DNA fragmentation into the vector.
F. Isolation of desired DNA fragments.
G. Amplification of gene of interest.
H. Transfer of Recombinant DNA into the host cell/organism.

The correct sequence of steps is:

(a) C → A → B → D → E → F → G → H
(b) A → D → C → B → F → E → G → H
(c) A → B → F → G → E → H → C → D
(d) H → F → G → E → A → D → B → C

Correct Answer: (c) A → B → F → G → E → H → C → D

Solution:Steps in producing recombinant DNA: Identification → Fragmentation → Isolation of fragments → Amplification → Ligation → Transfer → Obtaining gene product → Downstream processing.

6. Assertion (A): Scientists can cut apart and paste together DNA molecules at will, regardless of the source of the molecules. [I.A.S. (Pre) 2001]

Reason (R): DNA fragments can be manipulated using restriction endonucleases and DNA ligases.

Code:

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Correct Answer: (a) Both (A) and (R) are true, and (R) is the correct explanation of (A).

Solution:Restriction endonucleases cut DNA at specific sites, and DNA ligases join fragments. The 1978 Nobel Prize was awarded to Werner Arber, Daniel Nathans, and Hamilton O. Smith for these discoveries.

7. Which of the following pairs is correctly matched? [R.A.S./R.T.S. (Pre) (Re. Exam) 2013]

(a) DNA - Molecular Scissors
(b) Ligases - Molecular Scissors
(c) Ligases - Molecular Stitchers
(d) Restriction Endonucleases - Molecular Stitchers

Correct Answer: (c) Ligases - Molecular Stitchers

Solution:Ligases act as molecular stitchers, forming covalent bonds to repair and synthesize DNA fragments.

8. What is Cas9 protein that is often mentioned in news? [I.A.S. (Pre) 2019]

(a) A molecular scissors used in targeted gene editing
(b) A biosensor used in the accurate detection of pathogens in patients
(c) A gene that makes plants pest-resistant
(d) A herbicidal substance synthesized in genetically modified crops

Correct Answer: (a) A molecular scissors used in targeted gene editing

Solution:Cas9 protein (CRISPR associated protein 9) is actually a molecular scissors used in targeted gene editing. Its main function is to cut DNA and therefore it can alter a cell’s genome. In CRISPR-Cas9 gene editing technique, the ‘CRISPR’ stands for clustered regularly interspaced short palindromic repeats, which are specialized stretches of DNA. While the ‘Cas9’ is an enzyme that acts like a pair of molecular scissors capable of cutting strands of DNA. This technology was adapted from the natural defense mechanisms of bacteria and archaea. By delivering the Cas9 molecule complexed with a synthetic guide RNA (gRNA) into a cell, the cell’s genome can be cut at a desired location, allowing existing genes to be removed and/or new ones added.

9. ‘RNA interference (RNAi)’ technology has gained popularity in the last few years. Why? [I.A.S. (Pre) 2019]

It is used in developing gene silencing therapies.
It can be used in developing therapies for the treatment of cancer.
It can be used to develop hormone replacement therapies.
It can be used to produce crop plants that are resistant to viral pathogens.

Select the correct answer using the code given below:

(a) 1, 2, and 4
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1 and 4 only

Correct Answer: (a) 1, 2, and 4

Solution:RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA (messenger RNA) molecules. It is used in developing gene silencing therapies. RNAi is being explored for treating diseases like HIV/AIDS, hepatitis, Huntington disease, and cancer. Studies show that RNAi can specifically inhibit tumor growth by targeting oncogenes. Additionally, RNAi technology has made breakthroughs in developing virus-resistant crops. Hence, statements 1, 2, and 4 are correct, while statement 3 is incorrect as RNAi has no role in hormone replacement therapies.

10. What is the expanded form of the term ‘mRNA’ that has been widely discussed since the beginning of the pandemic? [69th B.P.S.C. (Pre) 2023]

(a) Messenger Ribonucleic Acid
(b) Mutant Ribonucleic Acid
(c) Modified Ribonucleic Acid
(d) Mnemonic Ribonucleic Acid

Correct Answer: (a) Messenger Ribonucleic Acid

Solution:‘MRNA’ stands for messenger ribonucleic acid. These are single-stranded molecules that carry genetic code from DNA in a cell's nucleus to ribosomes, which produce proteins in cells. Researchers have been studying mRNA technology for years, and it was used in COVID-19 vaccines. mRNA vaccines trigger an immune response without containing a live virus, reducing disease risk.

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