$$[H^+] = 1 \times 10$$^{-4}$$ \, M$$

Question 1

Which of the following best explains why water is an excellent solvent for many biological molecules?

Accepted Answer

Water molecules are polar, allowing them to surround and separate ions and polar molecules.

Question 2

A radioactive isotope of carbon, carbon-14, is used in radiometric dating. What makes carbon-14 different from carbon-12?

Accepted Answer

Carbon-14 has more neutrons than carbon-12.

Question 3

Which of the following statements about ionic bonds is correct?

Accepted Answer

Ionic bonds result from the attraction between oppositely charged ions.

Question 4

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \, M$$

Question 5

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction in which two molecules are joined together with the removal of a water molecule.

Question 6

Why do cell membranes of microbes living in Arctic water likely contain more unsaturated fatty acids than those in hot springs?

Accepted Answer

Unsaturated fatty acids increase membrane fluidity at low temperatures.

Question 7

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

Accepted Answer

Providing long-term energy storage

Question 8

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

Accepted Answer

They stabilize the three-dimensional shapes of large molecules like proteins and DNA.

Question 9

Which of the following statements about ATP (adenosine triphosphate) is correct?

Accepted Answer

ATP stores energy in the bonds between its phosphate groups.

Question 10

A peptide bond is formed between two amino acids by which type of reaction?

Accepted Answer

Dehydration synthesis

Question 11

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A compound is a molecule composed of more than one element.

Question 12

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

Accepted Answer

DNA strands are antiparallel and held together by hydrogen bonds between complementary bases.

Question 13

Which of the following best explains why decomposition reactions are exothermic?

Accepted Answer

They release energy as bonds in larger molecules are broken to form smaller, more stable products.

Question 14

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

Accepted Answer

Water remains liquid across a wide range of temperatures.

Question 15

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

Accepted Answer

A buffer prevents drastic changes in pH by absorbing or releasing H+ ions.

Question 16

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

Accepted Answer

Genetic information storage

Question 17

Which of the following statements about phospholipids is correct?

Accepted Answer

Phospholipids have hydrophilic heads and hydrophobic tails, forming the basis of cell membranes.

Question 18

Which of the following best explains why the neutralization of an acid by a base often produces water?

Accepted Answer

The H+ from the acid combines with the OH− from the base to form H2O.

Question 19

Which of the following is a correct statement about isotopes?

Accepted Answer

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

Question 20

Which of the following is a real-life application of the concept of electronegativity in microbiology?

Accepted Answer

The ability of water to dissolve salts due to its polar covalent bonds.

Chapter 2: The Chemistry of Microbiology – Structured Study Notes

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