Which one of the following statements about viruses is correct ? (a) Viruses possess their own metabolic system. (b) All viruses contain both RNA and DNA. (c) Viruses are obligate parasites. (d) Nucleic acid of viruses is known as capsid.
Option C Viruses contain a protein coat known as capsid which encloses a single type of nucleic acid, either RNA or DNA. They do not have enzymes for protein synthesis. They multiply only inside the living host cell and for multiplication they take over the machinery of the host cell. Thus viruses are obligatory intercellular parasites. They lack cell division and enzymes for protein synthesis. They do not have cell organelles like mitochondria, Golgi complex, lysosomes, ribosomes etc. so they cannot live or reproduce separately.
