Question 1

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

Accepted Answer

Water molecules are polar, allowing them to surround and interact with charged and polar solutes.

Question 2

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-4}$$ M. What is the pH of this solution?

Accepted Answer

$$4$$

Question 3

Which of the following statements about the structure of an amino acid is CORRECT?

Accepted Answer

All amino acids have a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable R group.

Question 4

Which property of water is MOST directly responsible for the ability of trees to transport water from roots to leaves?

Accepted Answer

Cohesion due to hydrogen bonding

Question 5

Which of the following best describes the difference between a polar covalent bond and a nonpolar covalent bond?

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons due to differences in electronegativity, while nonpolar covalent bonds involve equal sharing.

Question 6

A protein is exposed to high heat and strong acid. Which levels of protein structure are most likely to be disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures

Question 7

Which of the following functional groups is acidic and found in amino acids?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 8

Which of the following statements about isomers is TRUE?

Accepted Answer

Isomers have the same molecular formula but different structures.

Question 9

A buffer solution is important in biological systems because it:

Accepted Answer

Minimizes changes in pH when small amounts of acid or base are added.

Question 10

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds hold water molecules farther apart in ice, making it less dense than liquid water.

Question 11

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

Accepted Answer

A solution with pH 3 has ten times more $$[H^+]$$ than a solution with pH 4.

Question 12

Which of the following is a correct statement about the formation of macromolecules?

Accepted Answer

Polymers are formed from monomers by condensation (dehydration synthesis) reactions.

Question 13

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

Accepted Answer

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

Question 14

Which of the following is a function of nucleic acids in living organisms?

Accepted Answer

Encode and transmit genetic information

Question 15

Which of the following statements about protein structure is correct?

Accepted Answer

The tertiary structure is stabilized by interactions between R groups of amino acids.

Question 16

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Their polar head groups interact with water, while their hydrophobic tails avoid water.

Question 17

Which of the following is a property of the carboxyl group ($$-COOH) $$found in amino acids?

Accepted Answer

It is polar, soluble, and has acidic properties.

Question 18

Which of the following statements about hydrogen bonds is TRUE?

Accepted Answer

Hydrogen bonds are weak, non-covalent interactions important for the structure of water and biomolecules.

Question 19

A mutation changes a single amino acid in a protein. Which levels of protein structure could be affected?

Accepted Answer

Primary, secondary, and tertiary structures

Question 20

Which of the following best describes the role of disulfide bridges in proteins?

Accepted Answer

They form between two cysteine residues and help stabilize tertiary and quaternary structures.

Small Molecules and the Chemistry of Life: Foundations for Biological Macromolecules

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