Answer:A) proteins are useful as enzymes, hormones etc.
B) the building block of protein are amino acids
Further explanation below
Explanation: A) proteins are polymers formed by several chains of amino acids. They occur in living tissue and form 50 -- 60% of the total dry mass of the living cell. Proteins found in the membrane are used as structural integrity. Some proteins are catalytic in nature and are such are used as enzymes. They also occur as hormones. Proteins help in the transport of substances across the cell membrane, when they are found in the cell membrane.
B) the building block of protein are amino acids. They undergo condensation reaction to form proteins.
The structure of amino acid is in the attached photo.
R = the group that determine the name of the amino acid. It may be a hydrogen atom,an alkyl, an aryl, or carboxyl group.
H2N = the amino group
COOH = the carboxyl group
C = the alpha central carbon to which other groups are attached.
