Question 1

Which of the following best describes an isotope of an element?

Accepted Answer

An atom with the same number of protons but a different number of neutrons.

Question 2

Which of the following statements about covalent bonds is correct?

Accepted Answer

Covalent bonds form when two atoms share one or more pairs of electrons.

Question 3

A solution has a hydrogen ion concentration of $1 	imes 10^{-4}$ M. What is its pH?

Accepted Answer

$4$

Question 4

Which property of water allows it to moderate temperature changes in living organisms?

Accepted Answer

Its high heat capacity

Question 5

Which of the following best explains why salts are important in biological systems?

Accepted Answer

They dissociate into ions that help create electrical differences across cell membranes.

Question 6

Which of the following is a correct statement about acids and bases?

Accepted Answer

Acids dissociate to release H$^+$ ions, while bases bind H$^+$ or release OH$^-$ ions.

Question 7

A molecule of glucose ($C_6H_{12}O_6$) has a molecular weight of 180 Daltons. How many grams of glucose are present in 2 moles?

Accepted Answer

$360$ grams

Question 8

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction in which two monomers are joined by removing a molecule of water.

Question 9

Which of the following is NOT a function of carbohydrates in living organisms?

Accepted Answer

Catalyzing chemical reactions

Question 10

Which of the following statements about phospholipids is correct?

Accepted Answer

They are composed of a glycerol backbone, two fatty acids, and a phosphate group.

Question 11

A protein's tertiary structure is primarily stabilized by which of the following interactions?

Accepted Answer

Interactions between R groups, including hydrogen bonds, ionic bonds, disulfide bridges, and hydrophobic interactions

Question 12

Which of the following best explains why enzymes are sensitive to changes in pH?

Accepted Answer

pH changes can disrupt hydrogen and ionic bonds, altering the enzyme's active site.

Question 13

Which of the following is a correct pairing of nucleic acid bases in DNA?

Accepted Answer

Guanine pairs with cytosine

Question 14

Which of the following best describes the difference between L- and D-amino acids?

Accepted Answer

L- and D-amino acids are mirror images and not superimposable.

Question 15

Which of the following is a property of water that is critical for life?

Accepted Answer

It can absorb significant amounts of energy without a large change in temperature.

Question 16

A buffer solution is important in biological systems because it:

Accepted Answer

Prevents drastic changes in pH by absorbing or releasing H$^+$ ions.

Question 17

Which of the following best describes a hydrogen bond?

Accepted Answer

A bond formed when a hydrogen atom covalently bonded to O or N is attracted to another O or N atom.

Question 18

Which of the following is true about the antiparallel nature of DNA?

Accepted Answer

One strand runs 5' to 3' and the other runs 3' to 5'.

Question 19

Which of the following is a correct statement about the role of functional groups in organic molecules?

Accepted Answer

Functional groups determine the specific chemical reactivity and interactions of organic molecules.

Question 20

A patient is given a solution with a pH of 8.5. Which of the following best describes this solution?

Accepted Answer

It is slightly alkaline (basic).

Chapter 2: Chemical Principles in Microbiology

Study Guide - Practice Questions