Final answer:
The secondary structure refers to local folding patterns stabilized by hydrogen bonds, while the tertiary structure is the overall three-dimensional structure formed by further folding and bonding.
Step-by-step explanation:
The secondary structure of a protein refers to the local folding patterns of the protein's polypeptide chain. It is stabilized by hydrogen bonds between amino acids. The two main types of secondary structure are the alpha-helix and the beta-sheet.
The tertiary structure is the overall three-dimensional structure of the protein. It is formed by further folding and bonding of the secondary structure. Side chain interactions, such as hydrophobic interactions, hydrogen bonds, and disulfide bridges, contribute to the stability of the tertiary structure.
An example of secondary structure is the alpha-helix in proteins like keratin and myoglobin. An example of tertiary structure is the folding of an enzyme like lactase or the protein insulin.