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, 2 and 3
B. 2 and 3 only
C. 1 and 2 only
D. 1 and 3 only
Answer: Option D
Solution (By JKSSB Mock Tests)
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:
Alexander Fleming discovered penicillin in 1928 from the mold Penicillium notatum (later renamed P. chrysogenum). Aspergillus niger is used for citric acid production, Saccharomyces is yeast, Rhizopus is a bread mold. Penicillin was the first true antibiotic and its mass production during WWII saved countless lives. It inhibits bacterial cell wall synthesis.
Consider the following statements about biotechnology:
1. Restriction enzymes cut DNA at specific sequences.
2. Ligase joins DNA fragments.
3. PCR amplifies DNA.
Which of the above is/are correct?
Explanation:
Restriction enzymes cut DNA at recognition sites, DNA ligase seals fragments, and PCR amplifies specific DNA sequences. All three are fundamental tools in biotechnology.
Explanation:
O negative blood group lacks A and B antigens on RBCs and Rh antigen. Hence, it can be transfused to any person without causing agglutination, making it the universal donor. AB positive has both antigens and is the universal recipient. Blood grouping is based on ABO and Rh systems. O negative is crucial in emergency transfusions when blood type is unknown.
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