AP BIOLOGY

Detailed explanation-1: -This statement about enzymes is true: Enzymes accelerate reactions by lowering the activation energy. Enzymes are proteins whose three-dimensional form is key to their function. Enzymes do not alter the overall change in free energy for a reaction.

Detailed explanation-2: -Enzymes are just one category of protein. There are many non-enzyme proteins in cells, and these proteins are also encoded by genes. Some genes encode a subunit of a protein, not a whole protein. In general, a gene encodes one polypeptide, meaning one chain of amino acids.

Detailed explanation-3: -Hence, all enzymes are proteins but all proteins are not enzymes. Enzymes are known to speed up the rate of the reaction that occurs in the living cells and hence are known as biocatalysts. Hence, both assertion and reason are correct.

Detailed explanation-4: -Every enzyme consists of a code of the letters “EC” followed by four numbers separated by periods. The first digit defines the general type of reaction catalysed by the enzyme and ranges from one to six. The second figure indicates the subclass. The third figure gives the sub-subclass.