5. Which of the following is (are) an advantage(s) of protein phosphorylation in regards to biochemical signaling? I. Phosphorylation is rapid and specific. II. Phosphorylation is enzymatically reversible. III. Phosphorylation can be amplified by cascade systems. IV. Phosphorylation results in covalent modification of enzymes. A) I, II, III, IV

A; 1, 11, 111, 1V

Explanation:

Protein Phosphorylation  is one of the post -translated  processes carried out to  modify the translated protein  either by  activating  or deactivating  it, with   conveniently bonding  of inorganic phosphate ion  to it. The reaction is reversible,with the forward reaction  catalysed by enzyme Kinase,  and the backward reaction  catalysed by Phophatases.

It is important in regulation of many biochemical activities in the cells and  regulation of  cellular  transport mechanisms.e,g Na+/K+  ATPase  for ions transports.

Phosphorylation usually  changed  the polarity of amino acid residues by replacing the hydrophobic -R group of protein with the polar phosphate groups. The protein thus  become activated This  increases its  hydrophilic properties needed for cell  signalling transduction .

However,dephosphorylation(removal of the phosphate group) removes the  hydrophilic effects and  signalling properties.

Thus all the above options are related to phosphorylation of protein.