3. PI of a protein is dependent on the number of acidic and basic amino acid residues in the protein.

The study of proteins is important because all the genes in cellular DNA house the program or code for a unique protein structure.

Explanation:

Within the science parlance, pl is the short way to write Isoelectric Point. It is the pH  (that is the acidity or basicity) of a solution at which the net charge of a protein becomes nil.

The surface, in most cases, is likely going to be negatively charged when the pH of that same solution is above the pl. When this occurs, molecules that have similar negative charges will tend to move away or be repelled.

It is useful to note that the structure of proteins comprises of 20 amino acids all of which are connected by peptide bonds.

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the answer to your question is b

i don't know, but does anyone wanna be friends? i'm doing my homework at 1: 49 in the morning : /