Proteins may function as . a. genetic material; b. cholesterol molecules; c. fat reserves; d. enzymes; e. all of the above

Explain how molecular chaperones facilitate protein folding in many different polypeptides, each with their own specific shape.

Different proteins are composed of different sequences of . a. sugars; b. lipids; c. fats; d. amino acids; e. carbohydrates

Why are proteins not considered to be a good candidate for the first living molecule? a. Their catalytic capability is not sufficient for most biological reactions. b. Their amino acid monomers were not likely present in the prebiotic soup. c. They cannot serve as a template for replication. d. They could not have polymerized from amino acid monomers under early Earth conditions.

Predict the effect on protein function if each polypeptide adopted only a single, inflexible shape based on its primary structure.

Based on what you know of the peptide bonds that link together amino acid residues, why would proline's side chain reduce the flexibility of the backbone?

Which structural level of a protein would be least affected by a disruption in hydrogen bonding? a. primary structure b. secondary structure c. tertiary structure d. quaternary structure

Make a concept map (see BioSkills 12) that relates the four levels of protein structure and shows how they can contribute to the formation of hemoglobin. Your map should include the following boxed terms: Primary structure, Secondary structure, Tertiary structure, Quaternary structure, Amino acid sequence, R-groups, αα-helices, and ββ-pleated sheets.

Most proteins are soluble in the aqueous environment of a cell. Knowing that, where in the overall three-dimensional shape of a protein would you expect to find amino acids with hydrophobic R groups?