Question 1

Which of the following best explains why water is considered a versatile solvent in biological systems?

Accepted Answer

Water's polarity allows it to form hydrogen bonds with many different solutes, enabling it to dissolve ionic and polar compounds.

Question 2

A solution is made by dissolving 0.1 mol of NaCl in 1 liter of water. Which property of water allows NaCl to dissolve so readily?

Accepted Answer

Water's ability to form hydrogen bonds with the Na+ and Cl- ions stabilizes them in solution.

Question 3

Which equation correctly represents the dissociation of water?

Accepted Answer

$$2H_2O \rightarrow H_3O^+ + OH^-$$

Question 4

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids increase the concentration of $$H^+$$ ions in solution, while bases decrease it.

Question 5

Which property of water is most responsible for the phenomenon of surface tension?

Accepted Answer

Cohesion due to hydrogen bonding between water molecules.

Question 6

A scientist is studying the effect of water's high specific heat on a coastal ecosystem. Which outcome is most likely due to this property?

Accepted Answer

Stable water temperatures that buffer organisms from extreme heat or cold.

Question 7

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electron pairs between atoms.

Question 8

Which statement correctly describes the difference between atomic number and mass number?

Accepted Answer

Atomic number is the number of protons; mass number is the sum of protons and neutrons.

Question 9

Which of the following is NOT one of the six elements that make up 96% of living matter?

Accepted Answer

Calcium

Question 10

A molecule of hemoglobin has a sickle shape due to a mutation. Which concept best explains how this change in shape affects its function?

Accepted Answer

Molecular shape determines the biological function of a molecule.

Question 11

Which functional group is characterized by a phosphorus atom bonded to four oxygen atoms and is important in energy transfer?

Accepted Answer

Phosphate group

Question 12

Which process requires water to be added to break a bond in a polymer?

Accepted Answer

Hydrolysis

Question 13

Which of the following statements about lipids is TRUE?

Accepted Answer

Lipids are hydrophobic molecules and do not dissolve in water.

Question 14

Which type of bond is responsible for the secondary structure of proteins?

Accepted Answer

Hydrogen bonds between the backbone atoms of the polypeptide chain

Question 15

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; unsaturated fatty acids have one or more double bonds.

Question 16

Which of the following is a correct statement about the pH scale?

Accepted Answer

A solution with pH 7 is neutral, with equal concentrations of $$H^+$$ and $$OH^-$$ ions.

Question 17

Which of the following is an example of a van der Waals interaction?

Accepted Answer

A weak attraction between molecules due to temporary partial charges.

Question 18

Which property of water allows ice to float on liquid water, and why is this important for aquatic ecosystems?

Accepted Answer

Water expands upon freezing, making ice less dense than liquid water, which insulates aquatic life below.

Question 19

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

Accepted Answer

A buffer is a substance that minimizes changes in pH by accepting or donating $$H^+$$ ions.

General Biology Study Guide: The Chemical Context and Molecular Diversity of Life

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