Question

Select the correct statement from the following :

• A. DNA from one organism will not band to DNA from other organism.
• B. Genetic engineering works only on animals and not yet successfully used on plants.
• C. There are no risk factors associated with r-DNA technology.
• D. The first step in PCR in heating which is used to seperate both the strands of gene of interest.

Answer 1

The Correct Option is D

Let's analyze each statement:

• (A) DNA from one organism will not band to DNA from other organisms
  This is incorrect. DNA from different organisms can hybridize or bind if they share similar sequences. The ability to bind is not restricted to organisms of the same species.
• (B) Genetic engineering works only on animals and not yet successfully used on plants
  This is incorrect. Genetic engineering has been successfully used in both plants and animals. Many genetically modified plants, like Bt cotton and golden rice, have been developed using genetic engineering techniques.
• (C) There are no risk factors associated with r-DNA technology
  This is incorrect. There are several risk factors associated with recombinant DNA (r-DNA) technology, including potential ecological impacts and safety concerns related to genetically modified organisms (GMOs).
• (D) The first step in PCR is heating which is used to separate both the strands of the gene of interest
  This is correct. The first step in the Polymerase Chain Reaction (PCR) is denaturation, where the DNA is heated to separate its two strands. This is followed by cooling to allow primers to bind to the single-stranded DNA.

The correct answer is (D) : The first step in PCR in heating which is used to seperate both the strands of gene of interest.

Answer 2

The correct answer is: (D) The first step in PCR is heating, which is used to separate both the strands of the gene of interest.

Polymerase Chain Reaction (PCR) is a powerful technique used to amplify specific DNA sequences. The process of PCR consists of several steps, each critical for the successful amplification of the DNA. These steps include:

• Denaturation: The first step in PCR is heating the reaction mixture to around 94-98°C. This heat causes the DNA double helix to separate, or "denature," into two single strands. This step is crucial because it allows the primers to bind to the single-stranded DNA templates in the next step.
• Annealing: The temperature is then lowered to allow primers to bind to their complementary sequences on the single-stranded DNA templates.
• Extension: The temperature is raised again to allow the DNA polymerase enzyme to synthesize the new DNA strand, starting from the primer and using the original strand as a template.

Thus, the first step in PCR is indeed heating, which is used to separate the DNA strands, and this makes (D) the correct answer.