Question 1

Which property of amino acid R-groups most directly determines whether an amino acid is hydrophilic or hydrophobic?

Accepted Answer

The charge and polarity of the side chain

Question 2

A mutation changes a glutamate residue (negatively charged) in hemoglobin to valine (nonpolar). What is the most likely consequence?

Accepted Answer

Hemoglobin molecules may stick together, causing sickle cell disease

Question 3

Which level of protein structure is directly responsible for the formation of alpha-helices and beta-pleated sheets?

Accepted Answer

Secondary structure

Question 4

What type of bond forms between the carboxyl group of one amino acid and the amino group of another during protein polymerization?

Accepted Answer

Peptide bond

Question 5

Which of the following interactions is NOT typically involved in stabilizing a protein's tertiary structure?

Accepted Answer

Peptide bonding

Question 6

A protein is denatured by heat. What is the most immediate effect on its function?

Accepted Answer

It loses its ability to catalyze reactions

Question 7

Which of the following best describes the directionality of a polypeptide chain?

Accepted Answer

It has a free amino group at the N-terminus and a free carboxyl group at the C-terminus

Question 8

Which of the following is a real-world example of a protein functioning as a molecular machine?

Accepted Answer

Ribosome synthesizing proteins

Question 9

What is the role of molecular chaperones such as Hsp90 in cells?

Accepted Answer

They facilitate proper protein folding and prevent aggregation

Question 10

Which of the following statements about prions is correct?

Accepted Answer

Prions are misfolded proteins that can induce normal proteins to misfold

Question 11

Which equation best represents the condensation reaction that forms a peptide bond between two amino acids?

Accepted Answer

$$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + H_2O$$

Question 12

Which of the following is NOT a function performed by proteins in living cells?

Accepted Answer

Storage of genetic information

Question 13

A protein consists of two identical polypeptide subunits. What is this structure called?

Accepted Answer

Homodimer

Question 14

Which of the following R-groups would most likely be found on the surface of a soluble protein in the cytoplasm?

Accepted Answer

Charged or polar R-groups

Question 15

Which of the following best explains why protein folding is energetically favorable?

Accepted Answer

Folding results in more chemical bonds and interactions, lowering potential energy

Question 16

Which of the following is a consequence of a single amino acid substitution in a protein's primary structure?

Accepted Answer

It can drastically alter the protein's function and properties

Question 17

Which of the following is true about the flexibility of proteins?

Accepted Answer

Many proteins are flexible and dynamic until they adopt their functional form

Question 18

Which of the following is a correct statement about the hierarchical nature of protein structure?

Accepted Answer

Primary structure determines secondary, tertiary, and quaternary structures

Question 19

Which of the following is a real-world application of understanding protein structure and function?

Accepted Answer

Designing drugs that target specific protein active sites

Question 20

Which of the following best describes the role of the active site in an enzyme?

Accepted Answer

It is the location where substrates bind and react

Protein Structure and Function: Chapter 3 Study Notes

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