Which of the following are true statements about proteins ?

Question

a) The shape and function of a protein is determined by the sequence of amino acids along the chain



b) The sequence of amino acids that make up a protein are known as the tertiary structure of the protein



c) Proteins are long complex molecules that have no regular structure. Even the presence of hydrogen
bonds is not enough to introduce structure



d) The primary structure of different protein molecules is created by hydrogen bonds between
an amine group on one molecule and a lone pair of electrons on an oxygen molecule in an adjacent protein



e) One type of secondary structure found in proteins is α-helix



f) The structrure of a protein that results from only hydrogen bonding between the side
chains of the different amino acids is called the tertiary structure

Answer 1

a) is true insofar as any regular shape that is present is ultimately determined by the sequence by virtue of the side chains in the polypeptide.

b) false. This is primary structure.

c) false. Hydrogen bonds are responsible for secondary structure

d) false. Primary structure is the order of amino acids.

e) is definitely true

f) false. This describes secondary structure.

Answer 2

a) False, although the structure is determined by the amino acid sequence, the function can be regulated by many others things, including which amino acids are phosphorylated (have a phosphate group attached). This is a major reason why some cells can become cancerous - because the normal protein function is changed by the extra phosphates.
b) False, the amino acid sequence is the primary structure
c) False, most proteins have regular structure; otherwise they could not be crystallized (many have been crystallized)
d) False; primary structure is amino acid sequence (as said above); hydrogen bonds (and other interactions between amino acids) make secondary structure
e) True; and other secondary structures include beta-sheet and random coil
f) False - although hydrogen bonding does contribute to tertiary structure, hydrophobic interactions also contribute to tertiary structure