Question 1

Which of the following best describes the monomers that make up proteins?

Accepted Answer

Amino acids

Question 2

A researcher is analyzing a polypeptide and wants to identify the α-carbon of an amino acid. Which atom should she look for?

Accepted Answer

The carbon atom bonded to both the amino and carboxyl groups

Question 3

Which functional group is always found in the R-group of glycine?

Accepted Answer

Hydrogen

Question 4

A solution contains an amino acid with a charged R-group. To convert the R-group to its non-ionized (uncharged) state, what should you do?

Accepted Answer

Decrease the pH of the solution

Question 5

Which of the following best describes the category of an amino acid with a methyl group as its R-group?

Accepted Answer

Non-polar

Question 6

When classifying an amino acid as polar, non-polar, or charged, do you consider its α-amino and α-carboxyl groups?

Accepted Answer

No, only the R-group is considered

Question 7

Which two atoms must be connected to form a peptide bond between two amino acids, such that the left amino acid is the N-terminus and the right is the C-terminus?

Accepted Answer

The carboxyl carbon of the left amino acid and the amino nitrogen of the right amino acid

Question 8

A polypeptide is denatured by heat. Which level of protein structure remains unchanged?

Accepted Answer

Primary

Question 9

Which level of protein structure is stabilized primarily by hydrogen bonds between backbone atoms, rather than R-group interactions?

Accepted Answer

Secondary

Question 10

Hemoglobin is composed of four polypeptide chains. What is the highest level of protein structure present in hemoglobin?

Accepted Answer

Quaternary

Question 11

Which of the following interactions is most likely to stabilize the tertiary structure of a protein in an aqueous environment?

Accepted Answer

Hydrophobic interactions among non-polar R-groups

Question 12

If two amino acids with oppositely charged R-groups are in the same polypeptide chain but not at the ends, how would they most likely interact at tertiary structure?

Accepted Answer

Ionic interactions

Question 13

Would the ionic interaction between two oppositely charged R-groups still be possible at very low pH?

Accepted Answer

No, because the carboxyl group would no longer be charged

Question 14

Which of the following best describes the information contained in the primary structure of a protein?

Accepted Answer

The sequence of amino acids

Question 15

A mutation changes a single amino acid in a protein. Which level(s) of protein structure could be directly affected?

Accepted Answer

Primary, secondary, tertiary, and quaternary

Question 16

Which of the following proteins is a gated ion channel involved in cystic fibrosis?

Accepted Answer

CFTR

Question 17

Which protein is responsible for catalyzing the transfer of a fucose residue from GDP-fucose to the precursor oligosaccharide chain on glycoproteins?

Accepted Answer

FUT1

Question 18

A patient has a mutation in the gene encoding the ABO protein. Which type of enzyme is most likely affected?

Accepted Answer

Glycosyltransferase

Question 19

Which of the following best describes a G-protein coupled receptor (GPCR)?

Accepted Answer

A membrane protein that transduces extracellular signals via G-proteins

Question 20

Which of the following is true about the quaternary structure of proteins?

Accepted Answer

It involves the assembly of multiple polypeptide subunits

Proteins: Structure, Function, and Amino Acids – Study Guide

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