Q: A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-5}$$ \, \text{M}$$

Question 1

Which property of water allows it to dissolve ionic compounds like sodium chloride, making it an excellent solvent for cellular reactions?

Accepted Answer

Its polarity, resulting in partial positive and negative charges

Question 2

A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-5}$$ \, 	ext{M}$$

Question 3

Which of the following best describes the difference between cohesion and adhesion in water molecules?

Accepted Answer

Cohesion is the attraction between water molecules; adhesion is the attraction between water and other substances.

Question 4

A buffer is added to a cell culture to maintain pH stability. If the pH drops from 7 to 6, by what factor has the hydrogen ion concentration increased?

Accepted Answer

By a factor of 10

Question 5

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

Accepted Answer

Storing genetic information

Question 6

Which type of bond forms between amino acids during protein synthesis?

Accepted Answer

Peptide bond

Question 7

Cell membranes are primarily composed of which type of lipid, and how are these molecules arranged?

Accepted Answer

Phospholipids arranged in a bilayer with hydrophobic tails facing inward

Question 8

Which of the following statements about carbohydrates is correct?

Accepted Answer

Polysaccharides are insoluble in water and serve as structural components in plants and fungi.

Question 9

Which molecule is the genetic material in cells and what is its structural difference compared to RNA?

Accepted Answer

DNA; it contains deoxyribose and is double-stranded

Question 10

A patient’s blood pH drops from 7.4 to 7.0. By what factor has the hydrogen ion concentration increased?

Accepted Answer

By a factor of $$10^{0.4}$$ \approx 2.5

Question 11

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonds between water molecules absorb heat energy.

Question 12

Which of the following is a correct description of a salt in biological systems?

Accepted Answer

A compound that dissociates into cations and anions in water

Question 13

Which of the following is a correct statement about the structure of phospholipids in cell membranes?

Accepted Answer

Phospholipids form a bilayer with hydrophobic tails facing each other.

Question 14

Which of the following is a function of cholesterol in cell membranes?

Accepted Answer

It maintains membrane fluidity at varying temperatures.

Question 15

Which of the following best describes the process of dehydration synthesis?

Accepted Answer

Joining monomers to form polymers by removing water

Question 16

Which of the following is true about the pH scale?

Accepted Answer

A change from pH 7 to pH 9 represents a 100-fold decrease in $$[H^+]$$ concentration.

Question 17

Which of the following is a correct match between a macromolecule and its monomer?

Accepted Answer

Carbohydrate – Monosaccharide

Question 18

Which level of protein structure is characterized by alpha helices and beta pleated sheets?

Accepted Answer

Secondary structure

Question 19

Which of the following is a correct statement about nucleic acids?

Accepted Answer

DNA is double-stranded and contains thymine.

Chemistry of Cell Biology Part II: Biological Molecules and Water

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