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

Question 1

Which of the following best explains why noble gases such as neon (Ne) and argon (Ar) are chemically unreactive?

Accepted Answer

Their outermost electron shell is completely filled.

Question 2

Which type of bond is primarily responsible for holding together the two strands of DNA in a double helix?

Accepted Answer

Hydrogen bonds

Question 3

A sodium atom (Na) reacts with a chlorine atom (Cl) to form sodium chloride (NaCl). What happens to the electrons during this reaction?

Accepted Answer

Sodium donates an electron to chlorine.

Question 4

Which of the following best describes an amphipathic molecule?

Accepted Answer

A molecule with both hydrophilic and hydrophobic regions

Question 5

Which functional group is present in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$\mathrm{-COOH})$$

Question 6

Which property of water allows insects like the water strider to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 7

Which of the following statements about phospholipids is correct?

Accepted Answer

They have a hydrophilic head and hydrophobic tails.

Question 8

What type of bond links adjacent monosaccharides in polysaccharides such as starch and cellulose?

Accepted Answer

Glycosidic bond

Question 9

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids contain only single bonds between carbon atoms, while unsaturated fatty acids contain one or more double bonds.

Question 10

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}$$ \ \mathrm{M}$$

Question 11

Which of the following is a function of salts in microbial cells?

Accepted Answer

They create electrical differences across membranes.

Question 12

Which of the following best explains why nonpolar molecules tend to aggregate in water?

Accepted Answer

They are repelled by water due to hydrophobic interactions.

Question 13

Which of the following bonds is the strongest under physiological conditions?

Accepted Answer

Covalent bond

Question 14

Which of the following is true about the primary structure of a protein?

Accepted Answer

It refers to the linear sequence of amino acids.

Question 15

Which of the following best describes the role of buffers in cells?

Accepted Answer

They maintain a constant pH by accepting or donating protons.

Question 16

Which of the following is a correct statement about the structure of nucleotides?

Accepted Answer

They contain a pentose sugar, a nitrogenous base, and a phosphate group.

Question 17

Which of the following is a real-life example of a protein denaturation event?

Accepted Answer

The loss of enzyme activity after boiling an egg.

Question 18

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

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 19

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

Accepted Answer

They serve as energy storage and structural components.

Question 20

Which of the following best explains why water is an excellent solvent for ionic and polar substances?

Accepted Answer

Water molecules form hydrogen bonds with ions and polar molecules, stabilizing them in solution.

Cell Chemistry: Foundations for Microbiology

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