Multiple Choice
Proteins can be denatured by all the following except __________.
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4. Protein Structure
Denaturation
Multiple Choice
What happens to a protein when it is denatured under conditions such as heat or extreme pH?
A
It is converted into a different protein with a new amino acid sequence through rearrangement of peptide bonds without breaking them.
B
It becomes covalently cross-linked into a new, stable structure that permanently increases its catalytic activity.
C
It loses its native secondary and tertiary structure (and possibly quaternary structure) due to disruption of noncovalent interactions, often leading to loss of function.
D
Its primary structure is cleaved into free amino acids by hydrolysis of peptide bonds.
Verified step by step guidance1
Understand that protein structure is organized into four levels: primary (amino acid sequence), secondary (local folding like alpha-helices and beta-sheets), tertiary (overall 3D shape), and quaternary (assembly of multiple polypeptides).
Recognize that denaturation affects the higher-order structures (secondary, tertiary, and quaternary) but does not break the peptide bonds that form the primary structure.
Identify that denaturation occurs due to disruption of noncovalent interactions such as hydrogen bonds, ionic bonds, hydrophobic interactions, and van der Waals forces, which stabilize the protein's folded shape.
Note that common denaturing agents include heat and extreme pH, which alter the environment and cause the protein to unfold or lose its native conformation.
Conclude that denaturation often leads to loss of the protein's biological function because the specific 3D structure required for activity is lost, but the amino acid sequence remains intact.
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