Which of the following is found in viruses and NOT in cells?
a
nucleolus
b
protein capsid
c
cytosol
d
ribosomes
b) protein capsid
The correct answer is option b: protein capsid.
Viruses are infectious agents that consist of genetic material (DNA or RNA) enclosed in a protein coat called a capsid. This capsid protects the genetic material and allows the virus to attach to host cells. Cells, on the other hand, do not possess protein capsids.
The answer to the question is option b: protein capsid.
To determine the correct answer, we need to compare the characteristics of viruses and cells. Viruses are composed of genetic material (either DNA or RNA) enclosed in a protein coat called the capsid. This protein capsid provides protection for the genetic material and helps the virus to attach to host cells. On the other hand, cells are the basic structural and functional units of all living organisms and contain various components such as a nucleus, cytosol, ribosomes, and nucleolus.
Now, let's analyze the options:
a) Nucleolus: Nucleolus is a structure found within the nucleus of cells. It is responsible for the assembly of ribosomes. Therefore, nucleoli are found in cells and not in viruses.
b) Protein capsid: As mentioned earlier, viruses have a protein capsid, which is not found in cells.
c) Cytosol: Cytosol refers to the fluid component of the cytoplasm in cells. It contains various molecules and organelles. Therefore, cytosol is found in cells and not exclusive to viruses.
d) Ribosomes: Ribosomes are cellular structures responsible for protein synthesis. They are found in both eukaryotic and prokaryotic cells. Therefore, ribosomes are present in cells and not exclusively in viruses.
By comparing the characteristics of viruses and cells, we can conclude that the structure found in viruses and not in cells is the protein capsid (option b).