Question

Your body contains tens of thousands of different proteins, each with a specific structure and function. The unique three-dimensional shape of each of these diverse proteins is based on several superimposed levels of structure. Which of the following statements is/are accurate descriptions of proteins? Select all that are correct. The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene. The 20 amino acids found in proteins differ in the composition of their R groups. Secondary structures, which include the alpha helix or beta pleated sheet, are held together by ionic bonds between R groups. Tertiary structure is the overall shape of a polypeptide, which may be stabilized by hydrophobic interactions and ionic bonds. Quaternary structure is only found in proteins that have more than one polypeptide subunit

Answer 1

Answer:

A) The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene.

B) The 20 amino acids found in proteins differ in the composition of their R groups.

D) Quaternary structure is only found in proteins that have more than one polypeptide subunit

Explanation: Proteins can be categorized in 4 by the type of structure they have.

The Primary Structure is based on the plain sequence order of amino acids in the chain, which is the same as coded by the DNA.

The Secondary Structure depends on the hydrogen bonds that amino acids form (α-helix or β-sheets)

The Tertiary Structure is based on the three-dimensional foldings that a single protein (monomeric protein) or polypeptide chain can acquire, and it's mainly driven by non-hidrophobic interactions.

The Quaternary Structure is the one that a group of monomeric proteins  can acquire, by adding two or more subunits (polypeptide protein).

Proteins are based on 20 amino acids, all of them are formed by a amine group (NH2-), a carboxyl group (COOH-) and specific side chain (R-group( which is unique in every amino acid. Amino acids can be classified as Essential or Non-Essential amino acids, if the body can produce them or not.