Question 1

Which of the following best describes a hydrogen bond?

Accepted Answer

An electrostatic interaction between a partially positive hydrogen atom and a partially negative atom.

Question 2

In an aqueous environment, which bond is generally the weakest?

Accepted Answer

Ionic bond

Question 3

Which of the following functional groups is classified as basic at physiological pH?

Accepted Answer

Amino group

Question 4

A solution contains both an acid and a base. If the acid donates a proton and the base accepts it, what is the effect on the pH of the solution?

Accepted Answer

The pH does not change because the proton is transferred but not lost from the solution.

Question 5

Which of the following statements about hydrophobic and hydrophilic substances is correct?

Accepted Answer

Hydrophilic substances contain polar covalent bonds and are capable of making hydrogen bonds in water.

Question 6

Which of the following is NOT a polymer?

Accepted Answer

Lipid

Question 7

A peptide bond is formed between which two groups of amino acids?

Accepted Answer

The carboxyl group of one amino acid and the amino group of another

Question 8

Which level of protein structure is directly determined by the sequence of amino acids?

Accepted Answer

Primary structure

Question 9

Which of the following statements about secondary protein structure is TRUE?

Accepted Answer

It is stabilized by hydrogen bonds between the peptide backbone atoms.

Question 10

A mutation changes a hydrophobic amino acid on the surface of a protein to a polar amino acid. What is the most likely effect on the protein's structure?

Accepted Answer

The protein may become destabilized because the new polar amino acid may disrupt hydrophobic interactions.

Question 11

Which of the following best explains why proteins can have such diverse functions?

Accepted Answer

Proteins are made of amino acids that can be arranged in many sequences and fold into a variety of structures.

Question 12

Which of the following statements about SDS-PAGE is correct?

Accepted Answer

SDS coats proteins in negative charge, allowing them to be separated by size.

Question 13

If a protein is denatured by heat, which bonds are most likely to be broken first?

Accepted Answer

Hydrogen and ionic bonds

Question 14

Which of the following best describes the role of molecular chaperones?

Accepted Answer

They assist in the folding of polypeptide chains into functioning proteins.

Question 15

Which of the following is a correct pairing of a functional group and its property?

Accepted Answer

Carboxyl group – acidic

Question 16

Which of the following best explains why hydrophobic amino acids are often found in the interior of globular proteins?

Accepted Answer

They avoid contact with water, stabilizing the protein's folded structure.

Question 17

Which of the following statements about nucleotides is correct?

Accepted Answer

A nucleotide is composed of a phosphate group, a 5-carbon sugar, and a nitrogenous base.

Question 18

Which of the following best describes the relationship between polypeptides and proteins?

Accepted Answer

A protein is one or more polypeptide chains that have been folded into their functional shape.

Question 19

Which of the following best explains why changing a single amino acid in a protein can affect its function?

Accepted Answer

It can disrupt many noncovalent interactions and change the shape of the protein.

Question 20

Which of the following is the correct order of bond strength in an aqueous environment, from strongest to weakest?

Accepted Answer

Covalent \u003e ionic \u003e hydrogen

General Biology Study Notes: Water, Macromolecules, and Protein Structure

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