When a protein is denatured by heat
Correct answer: B. its tertiary structure is destroyed but its primary structure remains intact
- A. its peptide bonds are hydrolysed and amino acids are released
- B. its tertiary structure is destroyed but its primary structure remains intact
- C. its amino acid sequence is rearranged
- D. it becomes more soluble and more active
Explanation
Heat breaks the relatively weak hydrogen, ionic and hydrophobic interactions that hold the chain in its three dimensional shape, so the protein unfolds and loses function, but the strong covalent peptide bonds of the backbone survive. This is why boiling an egg changes the albumen irreversibly without breaking it into amino acids. Denatured proteins usually become less soluble, which is why the egg white turns opaque.
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About Proteins
Proteins are polymers of amino acids joined by peptide bonds, and their function depends on primary, secondary, tertiary and quaternary structure. The topic covers fibrous and globular proteins, enzymes, antibodies, hormones and transport proteins, as well as denaturation by heat or extreme pH.
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