NEET Practice Questions (MCQs) with Answers & Solutions

fact 

Molecular medicine is a broad field that improves the diagnosis of diseases, is used in gene therapy, and helps in understanding several diseases like Alzheimer's and Parkinson's diseases. Therefore, all the options provided are correct.

Translation is the process by which the genetic code carried by mRNA is decoded to produce the specific sequence of amino acids in a polypeptide chain. DNA is not directly involved in translation; instead, mRNA, tRNA, and ribosomes play key roles in this process.

Transcription begins when RNA polymerase binds to the promoter site on the DNA. This enzyme is responsible for synthesizing RNA by following the sequence of the DNA template strand.

The operon concept was actually given by Jacob and Monod, not by Hershey and Chase. The separation of DNA fragments is most commonly done by gel electrophoresis, not by centrifugation. Therefore, both the assertion and the reason are false.

Both Assertion (A) and Reason (R) are true. Restriction endonucleases are indeed used to cut DNA into sections, and ligase is used to join DNA nucleotides. However, the reason does not directly explain the assertion. The correct explanation for the use of restriction endonucleases is that they recognize specific sequences in DNA and cut them, which is different from the function of ligase, which joins DNA fragments.

Both Assertion (A) and Reason (R) are true. Abraham Lincoln has been analyzed for Marfan's syndrome, and DNA fingerprint technology can indeed be used to diagnose inherited disorders. However, the reason provided does not explain the assertion directly; it is an additional benefit of the technology.

Both Assertion (A) and Reason (R) are true, and Reason (R) correctly explains Assertion (A). Helicase is called unwindase because it uncoils the DNA helix by breaking the hydrogen bonds between complementary bases, thereby splitting it into single strands.

The formation of the lagging strand is indeed slower than the leading strand because it is synthesized in short, discontinuous segments known as Okazaki fragments. This is due to the fact that DNA polymerase can only synthesize DNA in the 5' to 3' direction, and the lagging strand template is oriented in the 3' to 5' direction. Therefore, the synthesis of the lagging strand begins a bit later than the leading strand as it must wait for the replication fork to open further. Hence, both Assertion (A) and Reason (R) are true, and Reason (R) correctly explains Assertion (A).