What two functional groups are bound to the central carbon of every free amino acid monomer?

a. an R-group and a hydroxyl group

b. an amino group and a hydroxyl group

c. an amino group and a carboxyl group

What are the defining characteristics of a condensation reaction? a. Two monomers are covalently bonded together and a water molecule is produced. b. Two monomers are covalently bonded together and a water molecule is used up. c. A polymer is broken down into monomers and a water molecule is produced. d. A polymer is broken down into monomers and a water molecule is used up.

What type of bond is directly involved in the formation of an α-helix? a. peptide bonds between amino acid residues b. hydrogen bonds between amino acid residues c. van der Waals interactions between nonpolar residues d. disulfide bonds between cysteine residues

What type of information is used to direct different polypeptides to fold into different shapes?

If a cell were to use only 10 of the 20 possible amino acids, how much effect would you expect this to have on protein diversity? Calculate and compare the number of different sequences that can be generated by randomly assembling either 10 or 20 amino acids into peptides that are five residues long.

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

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?

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.