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

Question 1

Which property of water is primarily responsible for its ability to dissolve ionic compounds such as sodium chloride (NaCl)?

Accepted Answer

Its polarity, which allows it to surround and separate ions

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 a buffer in biological systems?

Accepted Answer

A substance that maintains stable pH by neutralizing acids and bases

Question 4

What is the main reason why carbon is able to form such a wide variety of biological molecules?

Accepted Answer

It has four valence electrons, allowing it to form four covalent bonds

Question 5

Which of the following statements about the pH scale is correct?

Accepted Answer

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

Question 6

Which type of macromolecule is primarily responsible for speeding up biochemical reactions in cells?

Accepted Answer

Proteins (enzymes)

Question 7

A protein's tertiary structure is stabilized mainly by which type of interactions?

Accepted Answer

A combination of hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges

Question 8

Which of the following is a correct description of a phospholipid's structure in cell membranes?

Accepted Answer

It has a hydrophilic head and two hydrophobic tails

Question 9

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

Accepted Answer

Forming genetic material

Question 10

Which of the following statements about DNA and RNA is correct?

Accepted Answer

DNA contains deoxyribose sugar and is double stranded; RNA contains ribose sugar and is single stranded

Question 11

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

Accepted Answer

Approximately 2.5 times ($$10^{0.4}$$ \approx 2.5$$)

Question 12

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 13

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

Accepted Answer

Joining two amino acids to form a dipeptide and releasing water

Question 14

Which property of water is most important for the movement of water up plant stems (capillary action)?

Accepted Answer

Cohesion and adhesion

Question 15

Which of the following is a correct statement about monosaccharides?

Accepted Answer

They are the building blocks of carbohydrates

Question 16

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

Accepted Answer

It is a polysaccharide composed of glucose units

Question 17

Which of the following best describes the difference between an acid and a base?

Accepted Answer

An acid increases $$[H^+] in $$solution, while a base increases $$[OH^-]$$

Question 18

Which of the following is a correct description of a nucleotide?

Accepted Answer

A molecule composed of a phosphate group, a pentose sugar, and a nitrogenous base

Question 19

Which of the following is a real-life consequence of failing to maintain stable pH in human cells?

Accepted Answer

Enzymes may denature and lose their function

Question 20

Which of the following is a correct statement about the hydrophobic effect in biological membranes?

Accepted Answer

Hydrophilic heads of phospholipids face the aqueous environment

Chemistry of Cell Biology Part II: Biological Molecules and Water

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