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.

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

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.

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

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

Which of the following correctly describe an active site? Select True or False for each statement.

T/F It is the location in an enzyme where substrates bind.

T/F It is the place where a molecule or ion binds to an inactive enzyme to induce a shape change to make it active.

T/F It is the portion of an enzyme where chaperones bind to help enzymes fold.

T/F It is the site on an enzyme where catalysis occurs.

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