AP BIOLOGY

BIOCHEMISTRY

ENZYMES AND METABOLISM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What happens to an enzyme when it is denatured?
A
Activation energy is lowered.
B
It becomes stronger.
C
It loses its shape.
D
Activation energy is raised.
Explanation: 

Detailed explanation-1: -A denatured enzyme refers to an enzyme that has lost its normal three-dimensional, or tertiary, structure. Once an enzyme loses this structure and is denatured, it is no longer able to function. Therefore, any catalytic advantage is lost, and the biological reaction no longer proceeds at an increased rate.

Detailed explanation-2: -When the shape of an enzyme (and more specifically its active site) changes, it is no longer able to bind to its substrate. The enzyme is deactivated and no longer has an effect on the rate of the reaction. Enzymes can also be deactivated by other molecules.

Detailed explanation-3: -Denaturation is caused by the breaking of the bonds that hold the enzyme together in its three-dimensional shape. Heat can break hydrogen and ionic bonds, which disrupts the shape of the enzyme and will change the shape of the active site.

Detailed explanation-4: -Enzyme structures unfold (denature) when heated or exposed to chemical denaturants and this disruption to the structure typically causes a loss of activity. Protein folding is key to whether a globular protein or a membrane protein can do its job correctly.

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