AP BIOLOGY

Detailed explanation-1: -For example, insulin is a protein hormone that helps to regulate the blood glucose level. Proteins have different shapes and molecular weights; some proteins are globular in shape whereas others are fibrous in nature. For example, hemoglobin is a globular protein, but collagen, found in our skin, is a fibrous protein.

Detailed explanation-2: -Enzymes are proteins comprised of amino acids linked together in one or more polypeptide chains. This sequence of amino acids in a polypeptide chain is called the primary structure. This, in turn, determines the three-dimensional structure of the enzyme, including the shape of the active site.

Detailed explanation-3: -Hemoglobin, insulin, albumin, an maltose, which are composed of chains of amino acids, are examples of. composed of chains of amino acids.

Detailed explanation-4: -Insulin is a small globular protein containing two chains, A (21 residues) and B (30 residues) (Fig. 2.1A). Stored in the cell as a Zn2+-stabilized hexamer, the hormone dissociates in the bloodstream to function as a Zn2+-free monomer (Fig.

Detailed explanation-5: -Hemoglobin is an allosteric protein. When one heme group in hemoglobin binds oxygen, it is easier for successive oxygen molecules to bind at the remaining three sites. Thus, once oxygenation occurs at one heme, there is cooperation at all other sites in hemoglobin.