GATE BT 2022 • Q24
MCQ • 1 Mark
Section 2: General Biotechnology
Biomolecules, enzyme kinetics
Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
Which of the following is NOT used for generating an optimal alignment of two
nucleotide sequences?
Options:
-
(A) Gap penalties
-
(B) Match scores
-
(C) Mismatch scores
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(D) Nucleotide composition
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2022 Q.24)**
**1. Governing Concept**:
- **Topic**: Plant Biotechnology & Haploid Plant Production
- Haploid plants (containing a single set of chromosomes, $n$) can be produced via:
- **Anther culture / Microspore culture (Androgenesis)**: Culturing immature pollen grains.
- **Ovary / Ovule culture (Gynogenesis)**: Culturing unfertilized female gametes.
- **Distant hybridization followed by selective chromosome elimination** (e.g., *Hordeum bulbosum* method).
- **Shoot apical meristem culture** utilizes diploid somatic vegetative tissue to produce virus-free clonal **diploid ($2n$)** plants; it **cannot generate haploid plants**.
**2. Option Analysis**:
- **Option (A) is INCORRECT**: Anther culture is the primary method for producing androgenic haploids.
- **Option (B) is INCORRECT**: Microspore culture produces haploids.
- **Option (C) is INCORRECT**: Ovary culture yields gynogenic haploids.
- **Option (D) [Meristem / Somatic culture] is CORRECT**: Generates clonal diploid ($2n$) virus-free plants, never haploids.
**3. Final Answer**:
- **Correct Choice**: **D**
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