Question 1

Which of the following statements best describes the difference between an atom and an ion?

Accepted Answer

An atom has an equal number of protons and electrons, while an ion has an unequal number of protons and electrons.

Question 2

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

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 3

Which of the following best explains why water is a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, causing unequal sharing of electrons and partial charges on the molecule.

Question 4

Which type of chemical bond is primarily responsible for holding the two strands of DNA together?

Accepted Answer

Hydrogen bonds

Question 5

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

Accepted Answer

$$4$$

Question 6

Which of the following best describes the structure of a phospholipid and its role in cells?

Accepted Answer

A phospholipid has a hydrophilic phosphate head and two hydrophobic fatty acid tails, forming the primary component of cell membranes.

Question 7

Which of the following is a correct example of a dehydration synthesis reaction?

Accepted Answer

Glucose + Fructose $$\rightarrow$$ Sucrose + $$H_2O$$

Question 8

Which of the following macromolecules is primarily responsible for storing genetic information?

Accepted Answer

Nucleic acids

Question 9

Which of the following statements about saturated and unsaturated fatty acids is correct?

Accepted Answer

Saturated fatty acids have no double bonds between carbon atoms and are solid at room temperature.

Question 10

Which of the following best explains why cellulose cannot be digested by humans but can be digested by some microbes?

Accepted Answer

Humans lack the enzyme to break the $$\beta-1$$,4-glycosidic bonds in cellulose, but some microbes possess this enzyme.

Question 11

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

Accepted Answer

Storing genetic information

Question 12

A molecule of ATP contains which of the following components?

Accepted Answer

Adenine, ribose, and three phosphate groups

Question 13

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

Accepted Answer

DNA contains deoxyribose and thymine, while RNA contains ribose and uracil.

Question 14

Which of the following elements is able to form the greatest number of covalent bonds?

Accepted Answer

Carbon

Question 15

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophilic heads interact with water while their hydrophobic tails avoid water, resulting in a bilayer structure.

Question 16

Which of the following is a correct statement about the pH preferences of microbes?

Accepted Answer

Most microbes prefer pH values between 6.5 and 8.5.

Question 17

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

Accepted Answer

The sequence of amino acids in a polypeptide chain

Question 18

Which of the following is a real-life example of an organism adapted to an acidic environment?

Accepted Answer

Helicobacter pylori, which causes ulcers in the human stomach (pH 1.5-2)

Question 19

Which of the following best explains why glucose is soluble in water?

Accepted Answer

Glucose is a polar molecule with many hydroxyl groups that can form hydrogen bonds with water.

Chemical Principles in Microbiology: Atoms, Bonds, and Biological Macromolecules

Study Guide - Practice Questions