$$pH = -\log_{10}(1 \times 10$$^{-7}$$) = 7$$

Question 1

Which of the following best describes why water is considered a temperature buffer in biological systems?

Accepted Answer

Water's high specific heat allows it to absorb and release large amounts of heat with little temperature change due to hydrogen bonding.

Question 2

Which of the following statements about covalent bonds is correct?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms.

Question 3

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-7}$$ M. What is its pH?

Accepted Answer

$$pH = -\log_{10}(1 	imes 10$$^{-7}$$) = 7$$

Question 4

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

Accepted Answer

$$A + B \rightarrow AB$$

Question 5

Which property of phospholipids is essential for the formation of biological membranes?

Accepted Answer

They have both polar and nonpolar regions, allowing them to form bilayers in water.

Question 6

What is the main difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more double bonds.

Question 7

Which of the following best explains why NaCl dissolves in water?

Accepted Answer

Water's polarity allows it to surround and separate Na$$^+$$ and Cl$$^-$$ ions, overcoming the ionic bond.

Question 8

Which of the following is true about the structure of DNA?

Accepted Answer

Adenine forms hydrogen bonds with thymine, and cytosine forms hydrogen bonds with guanine.

Question 9

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases energy as bonds are broken.

Question 10

Which of the following is a function of proteins in cells?

Accepted Answer

Enzymes that speed up chemical reactions.

Question 11

What is the molecular mass of a water molecule ($$H_2O) $$given the atomic masses: H = 1, O = 16?

Accepted Answer

$$2 	imes 1 + 16 = 18$$

Question 12

Which of the following best describes a peptide bond?

Accepted Answer

A covalent bond formed by dehydration synthesis between amino acids.

Question 13

Which of the following is a property of organic compounds?

Accepted Answer

They always contain carbon and hydrogen and are structurally complex.

Question 14

Which of the following is true about the pH scale?

Accepted Answer

A solution with $$[H^+] = 1 	imes 10$$^{-3}$$ M has a pH of 3 and is acidic.

Question 15

Which of the following best describes the process of denaturation in proteins?

Accepted Answer

Loss of protein shape and function due to hostile environments such as high temperature or extreme pH.

Question 16

Which of the following is a characteristic of RNA but not DNA?

Accepted Answer

Contains ribose and uracil.

Question 17

Which of the following best explains why enzymes are essential for life?

Accepted Answer

They speed up chemical reactions by lowering activation energy.

Question 18

Which of the following is true about the hydrolysis of ATP?

Accepted Answer

ATP hydrolysis releases energy by breaking a phosphate bond: $$ATP + H_2O ightarrow ADP + P_i + 	ext{Energy}$$

Question 19

Which of the following is a correct statement about macromolecules?

Accepted Answer

Macromolecules are polymers formed by joining monomers through dehydration synthesis.

Chapter 2: Chemical Principles – Foundations for Microbiology

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