Question 1

Which of the following statements best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 2

Which of the following elements is NOT one of the four most abundant elements in living organisms (CHONP)?

Accepted Answer

Sulfur

Question 3

A neutral atom of sodium (Na) has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$

Question 4

Which of the following best explains why atoms form chemical bonds?

Accepted Answer

To achieve a full valence shell of electrons.

Question 5

Which type of bond is formed when electrons are shared unequally between two atoms?

Accepted Answer

Polar covalent bond

Question 6

What is the main function of buffers in biological systems?

Accepted Answer

To maintain a constant pH when acids or bases are added.

Question 7

Which of the following reactions best represents the action of a base in water?

Accepted Answer

$$\mathrm{NaOH} \rightarrow \mathrm{Na}^+ + \mathrm{OH}^-$$

Question 8

Which property of water is primarily responsible for its ability to form hydrogen bonds?

Accepted Answer

Its high electronegativity difference between hydrogen and oxygen.

Question 9

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction that joins monomers to form polymers by removing water.

Question 10

Which of the following is a correct chemical formula for a simple carbohydrate (monosaccharide)?

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$

Question 11

Which of the following statements about protein structure is true?

Accepted Answer

Secondary structure arises from hydrogen bonding between backbone atoms.

Question 12

Which of the following best describes the difference between DNA and RNA nucleotides?

Accepted Answer

DNA contains deoxyribose, RNA contains ribose.

Question 13

Which of the following functional groups is NOT commonly found in biological molecules?

Accepted Answer

Methyl ($$-CH_3$)

Question 14

Which of the following best describes the role of chaperone proteins?

Accepted Answer

They assist in protein folding or refolding.

Question 15

Which of the following bonds is responsible for holding the two strands of DNA together?

Accepted Answer

Hydrogen bonds

Question 16

Which of the following is a property of acids in aqueous solution?

Accepted Answer

They increase the concentration of $$\mathrm{H}^+$$ ions.

Question 17

Which of the following best describes a Van der Waals bond?

Accepted Answer

A weak noncovalent interaction due to transient dipoles.

Question 18

Which of the following statements about ionic bonds is correct?

Accepted Answer

They involve the transfer of electrons from one atom to another.

Question 19

Which of the following best explains why carbon is an excellent building block for biological molecules?

Accepted Answer

It can form up to four covalent bonds with other atoms.

Question 20

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in a polypeptide chain.

Molecular Interactions: Atoms, Bonds, and Biomolecules

Study Guide - Practice Questions