Question 1

Which of the following best explains why water has a high heat capacity and is able to moderate temperature changes in living organisms?

Accepted Answer

Water molecules form extensive hydrogen bonds, which absorb and release heat slowly.

Question 2

A patient’s blood pH is measured at 7.20. Which condition does this indicate, and what is a possible physiological consequence?

Accepted Answer

Acidosis; risk of coma

Question 3

Which statement correctly describes the difference between cations and anions?

Accepted Answer

Cations have lost electrons and have a positive charge; anions have gained electrons and have a negative charge.

Question 4

Which equation represents the dissociation of sodium chloride in water, and what is the significance of the resulting ions?

Accepted Answer

$$\mathrm{NaCl} \rightarrow \mathrm{Na}^+ + \mathrm{Cl}^-$$; the ions act as electrolytes and conduct electrical current$

Question 5

Which of the following best describes the role of enzymes in metabolic reactions?

Accepted Answer

Enzymes act as biological catalysts, lowering activation energy and speeding up reactions.

Question 6

A solution has a pH of 5. Which of the following statements is true regarding its hydrogen ion concentration?

Accepted Answer

It has a higher hydrogen ion concentration than a solution with pH 7.

Question 7

Which type of chemical bond is primarily responsible for the formation of table salt (NaCl), and what is the driving force behind this bond?

Accepted Answer

Ionic bond; attraction between oppositely charged ions

Question 8

Which of the following best explains why nonpolar molecules like fats and oils do not dissolve in water?

Accepted Answer

Nonpolar molecules are hydrophobic and do not interact with water’s partial charges.

Question 9

Which equation represents a hydrolysis reaction, and what is its biological significance?

Accepted Answer

$$\mathrm{AB} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{A-H} + \mathrm{OH-B}$$; it breaks down complex molecules using water$

Question 10

A buffer system in the blood helps maintain pH by which mechanism?

Accepted Answer

By accepting or donating hydrogen ions to resist changes in pH

Question 11

Which of the following is true regarding isotopes of an element?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 12

Which of the following best describes the difference between kinetic and potential energy in biological systems?

Accepted Answer

Kinetic energy is the energy of motion; potential energy is stored energy, such as in chemical bonds.

Question 13

Which of the following is a consequence of strong acids and bases fully dissociating in water?

Accepted Answer

They produce a high concentration of hydrogen or hydroxide ions, drastically changing pH.

Question 14

Which of the following is a correct statement about the atomic structure of elements?

Accepted Answer

Protons and neutrons are found in the nucleus, while electrons occupy the electron cloud.

Question 15

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, resulting in partial charges on the molecule.

Question 16

Which of the following is a real-life example of an exergonic reaction in the human body?

Accepted Answer

Hydrolysis of ATP to ADP, releasing energy for cellular work

Question 17

Which equation represents a reversible chemical reaction, and what does equilibrium mean in this context?

Accepted Answer

$$\mathrm{A} + \mathrm{B} \rightleftharpoons \mathrm{AB}$$; the reaction can proceed in both directions until the rates are equal$

Question 18

Which property of water allows it to dissolve ionic compounds and polar molecules, making it an excellent solvent in biological systems?

Accepted Answer

Its ability to form hydrogen bonds due to partial charges

Question 19

Which of the following best describes the function of electrolytes in the human body?

Accepted Answer

They conduct electrical currents necessary for nerve and muscle function.

Question 20

Which of the following is true about the relationship between activation energy and reaction rate in biological systems?

Accepted Answer

Lower activation energy results in a faster reaction rate.

Basic Biochemistry for Anatomy & Physiology: Matter, Atoms, and Atomic Structure

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