Question 1

Which of the following best describes the structure of an amino acid in its ionized form in water?

Accepted Answer

The amino group is positively charged and the carboxyl group is negatively charged.

Question 2

A scientist discovers a new amino acid with a side chain containing only carbon and hydrogen atoms. Which property is most likely true for this amino acid?

Accepted Answer

It is hydrophobic and does not form hydrogen bonds with water.

Question 3

Which of the following is the correct sequence for the hierarchical levels of protein structure?

Accepted Answer

Primary → Secondary → Tertiary → Quaternary

Question 4

A mutation changes a single amino acid in hemoglobin from glutamic acid to valine. What is the most likely consequence?

Accepted Answer

Hemoglobin molecules will stick to one another, causing sickle cell disease.

Question 5

Which type of interaction is responsible for the formation of disulfide bonds in a protein’s tertiary structure?

Accepted Answer

Covalent bonding between sulfhydryl groups

Question 6

What is the main function of molecular chaperones in cells?

Accepted Answer

They facilitate proper protein folding and prevent aggregation.

Question 7

Which of the following best explains why enzymes are effective catalysts?

Accepted Answer

They hold substrates in a precise orientation at the active site.

Question 8

A protein is found to consist of two identical polypeptide subunits. What is the correct term for this structure?

Accepted Answer

Homodimer

Question 9

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

Accepted Answer

Genetic information storage

Question 10

Which equation represents the formation of a peptide bond between two amino acids?

Accepted Answer

$\mathrm{R_1{-}COOH} + \mathrm{R_2{-}NH_2} \rightarrow \mathrm{R_1{-}CO{-}NH{-}R_2} + \mathrm{H_2O}$

Question 11

Which of the following interactions is NOT involved in the tertiary structure of proteins?

Accepted Answer

Peptide bonds

Question 12

A protein is denatured by heat. What is the most likely outcome?

Accepted Answer

The protein will lose its normal function.

Question 13

Which property of amino acid side chains most directly affects the solubility of the amino acid in water?

Accepted Answer

The polarity and charge of the side chain

Question 14

Which of the following best describes a prion?

Accepted Answer

An infectious, misfolded form of a normal protein

Question 15

Which of the following is a real-world example of how a single amino acid change can affect protein function?

Accepted Answer

The change from glutamic acid to valine in hemoglobin causing sickle cell disease

Question 16

Which of the following is true about the directionality of a polypeptide chain?

Accepted Answer

The N-terminus is always written on the left.

Question 17

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.

Question 18

Which of the following is NOT a type of secondary structure found in proteins?

Accepted Answer

Disulfide bond

Question 19

Which of the following statements about protein folding is correct?

Accepted Answer

Protein folding is often spontaneous and results in a more stable, lower energy state.

Protein Structure and Function: Chapter 3 Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards