Consider statements about biotechnology: 1. Plasmids are used as vectors. 2. Restriction enzymes are found in viruses. 3. PCR requires DNA polymerase. Which are correct? MCQ with Answer and Explanation
Consider statements about biotechnology: 1. Plasmids are used as vectors. 2. Restriction enzymes are found in viruses. 3. PCR requires DNA polymerase. Which are correct?
A. 1 and 2 only
B. 1, 2 and 3
C. 2 and 3 only
D. 1 and 3 only
Answer: Option D
Solution (By JKExamLibrary)
Plasmids are small, circular, extrachromosomal DNA molecules in bacteria widely used as cloning vectors in genetic engineering. Restriction enzymes are part of the bacterial immune system, found in bacteria and archaea, not viruses, protecting them against bacteriophages. Polymerase Chain Reaction (PCR) requires a thermostable DNA polymerase (like Taq) to synthesize new DNA strands. Thus, statements 1 and 3 are correct.
Explanation:
Lactase is a brush border enzyme in the small intestine that hydrolyzes lactose (milk sugar) into its constituent monosaccharides. Maltase acts on maltose, sucrase on sucrose, amylase on starch. Lactose intolerance results from lactase deficiency.
Explanation:
Louis Pasteur, a French microbiologist, is famous for several groundbreaking contributions. He developed the process of pasteurization (heating liquids to kill harmful microbes). He also conclusively disproved the theory of spontaneous generation using his famous swan-neck flask experiment, demonstrating that life only arises from pre-existing life (biogenesis). He also developed vaccines for rabies and anthrax.
Explanation:
DNA is typically a double-stranded helical molecule carrying genetic information. Genes are specific sequences of DNA located linearly on chromosomes. RNA is generally single-stranded and contains the nitrogenous base uracil instead of thymine, which is found in DNA. Therefore, statements 1 and 3 are correct, while statement 2 is incorrect.
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