Mark argues that proteins within the body have two functions: structure and transport. Sara disagrees. Which significant function of proteins did Mark omit from his list? A. Proteins increase the speed of reactions in the body.

B. Proteins store energy that can be released when the body needs it.

C. Proteins form waxy, waterproof coverings.

D. Proteins store genetic information within cells.

A. Proteins increase the speed of reactions in the body

A. Proteins increase the speed of reactions in the body.

Explanation:

Majority of enzymes are proteins. Enzymes are biocatalysts which speed up rate of biochemical reactions in our body. Enzymes do so by two mechanisms (1) by lowering the activation energy & (2) by producing binding energy.

(1) By lowering the activation energy : Enzymes react with substrates and form a stable enzyme substrate complex which gives an alternate path for proceeding of reaction. This alternate path requires lower energy which results in rapid reactions.

(2) By producing binding energy: Whenever a substrate enters the active site of an enzyme it causes the displacement of water molecules from the active site of enzyme. Due to removal of water molecules the hydrogen bonds which water molecules were making with the enzyme break down. As we know breaking of bonds is an exothermic reaction i. e. energy is released when bonds get broken. This energy further speeds up the rate of reaction.

Catalase is an enzyme which has highest catalytic efficiency.