Question

"Synthesis of one protein cannot take place without the presence of another protein." Is this statement true or false and why?

Answer 1

Ribosomes are the cellular structures which mediate protein synthesis . They are composed of
1. RNA (ribo nucleic acid)
2. protein
hence ribosomes are also known as ribonucleoproteins (RNA + protein).

An important point to remember is that the actual linking of amino acid to synthesise the protein is carried out by the RNA and not by the protein. In the ribosome the RNA functions as the enzyme and hence ribosomes are also known an "ribozymes". The proteins present in the ribosome provide structural support to the RNA enabling it to perform protein synthesis. In the absence of protein , the RNA would fall apart and not be able to synthesise the protein. Hence the above statement is true.

Generally most of your enzymes are proteins , however ribosomes are an exception where the nucleic acid, RNA ,functions as an enzyme. So if somebody asks you whether all enzymes are proteins your answer should be " no"