Question 1

Which of the following best describes an atom?

Accepted Answer

The smallest chemical unit of matter

Question 2

What is the atomic number of an element?

Accepted Answer

The number of protons in the nucleus

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons

Question 4

Why do electrons not fly off the nucleus despite moving at high speeds?

Accepted Answer

They are attracted to the positively charged protons in the nucleus by electrostatic forces

Question 5

Which type of chemical bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent bond

Question 6

What is the main difference between polar and nonpolar covalent bonds?

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons, while nonpolar covalent bonds involve equal sharing

Question 7

Which of the following best explains why sodium and chlorine form an ionic bond?

Accepted Answer

They have vastly different electronegativities, resulting in electron transfer

Question 8

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

Accepted Answer

It is an excellent solvent due to its polarity

Question 9

A solution has a pH of 4. What does this indicate about the solution?

Accepted Answer

It has a high concentration of $$\mathrm{H^+}$$ ions and is acidic

Question 10

Which of the following best describes a buffer in biological systems?

Accepted Answer

A substance that prevents drastic changes in internal pH

Question 11

Which of the following is true about the formation of water during the neutralization of an acid by a base?

Accepted Answer

The $$\mathrm{H^+}$$ from the acid combines with the $$\mathrm{OH^-}$$ from the base to form $$\mathrm{H_2O}$$

Question 12

Which of the following is NOT a function of proteins in cells?

Accepted Answer

Long-term storage of genetic information

Question 13

Which of the following organic macromolecules is NOT composed of regular subunits and is hydrophobic?

Accepted Answer

Lipids

Question 14

What is the main energy currency of the cell, and how is energy released from it?

Accepted Answer

ATP; energy is released when phosphate bonds are broken

Question 15

Which of the following best explains why microbes living in Arctic waters have more unsaturated fatty acids in their membranes?

Accepted Answer

Unsaturated fatty acids keep membranes fluid at low temperatures

Question 16

Which of the following statements about nucleic acids is correct?

Accepted Answer

DNA is usually double-stranded and contains the genetic material for all organisms

Question 17

Which of the following best describes a peptide bond?

Accepted Answer

A covalent bond formed between amino acids during protein synthesis

Question 18

Which of the following is a property of salts in biological systems?

Accepted Answer

They dissociate in water to form electrolytes

Question 19

Which of the following best describes an exchange reaction?

Accepted Answer

A reaction that involves both breaking and forming covalent bonds, with atoms moving from one molecule to another

Question 20

Which of the following is true about hydrogen bonds?

Accepted Answer

They are weaker than covalent and ionic bonds but essential for stabilizing large molecules

Chapter 2: The Chemistry of Microbiology – Study Notes

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