Enzyme vs DNA Size Comparison — NEET Biology
📚 Practice ConceptFrom what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
Which of the following statements regarding the fundamental concepts of genetic engineering are NOT correct? S1: DNA ligase is often referred to as 'molecular scissors' due to its ability to precisely cut DNA at specific recognition sequences. S2: The stable multiplication of an alien DNA piece in a host cell is ensured only when it is part of a chromosome having an origin of replication. S3: Genetic engineering techniques can overcome the limitation of traditional hybridisation by allowing selective introduction of desired genes. S4: A piece of alien DNA, upon integration into the host genome, is inherited along with the host DNA. S5: Plasmids are preferred vectors in genetic engineering because they are always integrated into the host cell's chromosomal DNA for replication.
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Correct answer: A — S1 and S5 only
Genetic engineering involves several key tools and principles, including restriction enzymes, DNA ligase, origin of replication, and vectors. S1: This statement is NOT correct. Restriction enzymes are referred to as 'molecular scissors' because they cut DNA, while DNA ligase joins DNA fragments. S2: This statement is correct. For an alien piece of DNA to multiply, it needs to be part of a chromosome with an origin of replication or be linked to a vector that has one. S3: This statement is correct. Genetic engineering allows for the isolation and introduction of only desired genes, overcoming the issue of introducing undesirable genes common in traditional hybridisation. S4: This statement is correct. If an alien piece of DNA integrates into the recipient's genome, it multiplies and is inherited along with the host DNA. S5: This statement is NOT correct. Plasmids are autonomously replicating extra-chromosomal DNA and replicate independently of the host chromosome; they are not always integrated into the host genome. Therefore, statements S1 and S5 are NOT correct.
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.