Question

Viruses have
A) DNA enclosed in a protein coat
B) Prokaryotic nucleus
C) Single chromosome
D) Either RNA or DNA

Answer 1

Hint: Viruses are very small microorganisms known to cause damage to the host they are living upon. The genetic material of the DNA is enclosed in a protein coat which also serves as a membrane. They rely on any type of host whether its genetic material is DNA or RNA for its reproduction.

Complete answer:
We all have studied about viruses and we know that they cannot reproduce on their own because viruses do not have the machinery to duplicate its genetic material so that it can be passed on to the further generation. This is because the viruses do not have any nucleus which can help them in copying its genetic material. So, considering this point we can rule out option B of viruses having a prokaryotic nucleus.
Talking about the morphology of the viruses, they have a head, neck, body and tail. The genetic material of viruses freely floats inside the head of the virus. The head of the virus is made up of the membrane of protein coat which keeps the genetic material safe. Now as they do not have a nucleus, they generally rely on the machinery of other host organisms to multiply their genetic material.
Since viruses do not have any specific host and they can attach to anyone, they need the genetic material to be the same as that of the host so that the host machinery easily multiplies it. So the viruses have special enzymes which can help them in converting their genetic material in any form.
Now since we know that viruses don’t have a specific genetic material, so it can be either RNA and DNA which can be enclosed within the protein coat and also the number of chromosomes are more than 1 so we can also rule out options A and C.

Therefore, the correct answer is option D.

Note:
 The reproduction mechanism of viruses is like, first they attach themselves to the host cell wall and transfer their genetic material inside the cell of the host. From there the genetic material enters into the nucleus where it replicates and the duplicated genetic material comes out of the nucleus and develops its own body at the cell wall and leaves the cell after multiplying and forming the body.