AP BIOLOGY

Detailed explanation-1: -A protein molecule is made from a long chain of these amino acids, each linked to its neighbor through a covalent peptide bond (Figure 3-1). Proteins are therefore also known as polypeptides.

Detailed explanation-2: -Chemical properties The one-letter symbol for an undetermined amino acid is X. The three-letter symbol Asx or one-letter symbol B means the amino acid is either asparagine or aspartic acid; Glx or Z means either glutamic acid or glutamine; and Xle or J means either leucine or isoleucine.

Detailed explanation-3: -A protein consists of one or more chains of amino acids (called polypeptides) whose sequence is encoded in a gene. Some amino acids can be synthesized in the body, but others (essential amino acids) cannot and must be obtained from a person’s diet.

Detailed explanation-4: -Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains. There are 20 different types of amino acids that can be combined to make a protein.

Detailed explanation-5: -Although amino acids may have other formulas, those in protein invariably have the general formula RCH(NH2)COOH, where C is carbon, H is hydrogen, N is nitrogen, O is oxygen, and R is a group, varying in composition and structure, called a side chain.