Q30. A clone produced by somatic cell nuclear transfer is most similar in nuclear DNA to:
[SSC MTS — Practice]
- (a) An unrelated sperm donor
- (b) The donor of the somatic-cell nucleus
- (c) Every animal of the same species
- (d) The gestational surrogate necessarily
Answer: (b) The donor of the somatic-cell nucleus
Explanation: The clone’s nuclear genome chiefly reflects the somatic nuclear donor. However, mitochondrial DNA generally derives from the recipient egg, and development is influenced by epigenetic and environmental factors. Therefore genetically related clones need not be phenotypically identical.
Q29. Golden Rice was developed chiefly to increase which nutrient precursor in edible grain?
[UPPCS (Pre) 2011]
- (a) Beta-carotene
- (b) Vitamin K
- (c) Vitamin B12
- (d) Vitamin C
Answer: (a) Beta-carotene
Explanation: Golden Rice accumulates beta-carotene, a provitamin A carotenoid, in rice endosperm through engineered biosynthetic pathways. Humans can convert beta-carotene into vitamin A. The crop does not directly manufacture vitamin B12 or automatically eliminate all malnutrition.
Q28. Reproductive cloning aims to:
[RRB NTPC — Practice]
- (a) Measure blood sugar only
- (b) Copy a single protein in vitro
- (c) Produce antibiotics from fungi
- (d) Produce a living individual from a cloned embryo
Answer: (d) Produce a living individual from a cloned embryo
Explanation: Reproductive cloning seeks development of a cloned embryo into an offspring. Therapeutic applications associated with nuclear transfer instead focus on deriving cells or tissues for research. Both involve important scientific limitations and ethical questions.
Q27. In molecular biology, gene cloning means:
[RRB Group D — Practice]
- (a) Staining bacterial spores
- (b) Producing an entire human being
- (c) Producing many copies of a chosen DNA fragment
- (d) Destroying chromosome ends
Answer: (c) Producing many copies of a chosen DNA fragment
Explanation: Gene cloning creates multiple copies of a selected DNA sequence, often using a vector replicated in a host cell. Molecular cloning is distinct from cloning a whole organism. The amplified gene may later be sequenced or expressed.
Q26. What is the major biological challenge in somatic cell nuclear transfer?
[CGPSC — Practice]
- (a) Maintaining the donor animal’s diet
- (b) Reprogramming a specialised nucleus to support embryo development
- (c) Eliminating all ATP from eggs
- (d) Producing only male offspring
Answer: (b) Reprogramming a specialised nucleus to support embryo development
Explanation: An adult somatic nucleus carries epigenetic patterns linked to specialised functions. Egg cytoplasm must reset many of those patterns to permit early development. Incomplete reprogramming contributes to the low efficiency and developmental problems observed in animal cloning.
Q25. What nutritional trait explains the significance of Golden Rice?
[UPSC CSE (Pre) 2010]
- (a) Presence of provitamin A in the grain
- (b) A threefold yield increase
- (c) Production of all essential amino acids
- (d) Vitamin D fortification
Answer: (a) Presence of provitamin A in the grain
Explanation: Golden Rice is notable for endosperm beta-carotene, which can be converted by the human body into vitamin A. Its intended public-health benefit addresses vitamin A deficiency. Enhanced provitamin A, rather than universal yield or protein gains, is its defining feature.
Q24. Who pioneered the DNA fingerprinting method in the 1980s?
[UPSC CDS — Practice]
- (a) Watson alone
- (b) Alexander Fleming
- (c) Gregor Mendel
- (d) Alec Jeffreys
Answer: (d) Alec Jeffreys
Explanation: Alec Jeffreys developed DNA fingerprinting based on highly variable regions of human DNA. The method transformed forensic identification and family relationship testing. Later technologies increasingly employed PCR-based short tandem repeat analysis for sensitive and standardised profiling.
Q23. Which scientist is widely known as the father of DNA fingerprinting in India?
[UPSC NDA — Practice]
- (a) S. N. Bose
- (b) C. V. Raman
- (c) Lalji Singh
- (d) Homi Bhabha
Answer: (c) Lalji Singh
Explanation: Lalji Singh played a pioneering role in establishing DNA fingerprinting technology and its applications in India. His work contributed to forensic genetics and population research. Internationally, the original DNA fingerprinting technique is credited to Alec Jeffreys.
Q22. An STR marker consists of:
[State PSC — Practice]
- (a) A region without any heritable sequence
- (b) A short DNA motif repeated consecutively
- (c) A long protein with no nucleotides
- (d) A chromosome composed only of RNA
Answer: (b) A short DNA motif repeated consecutively
Explanation: Short tandem repeats comprise short DNA motifs repeated end to end at specific genomic loci. Repeat counts can differ among individuals. Their high variability and PCR compatibility make STRs important for forensic profiling and relationship testing.
Q21. In forensic investigation, which evidence may provide DNA for analysis?
1. Blood cells;
2. bone;
3. root-bearing hair;
4. saliva.
[UPPCS (Pre) 2008]
- (a) All four
- (b) 2 and 3 only
- (c) 1 and 2 only
- (d) 1, 3 and 4 only
Answer: (a) All four
Explanation: Nucleated blood cells, bone tissue, hair roots and saliva containing shed cells can provide human DNA. Sample suitability depends on preservation, contamination and extraction method. Forensic laboratories use validated procedures and compare selected genetic markers.
