Anatomy & Physiology Exam Prep practice questions and answers 2026. Tap an option to test yourself — you'll see the correct answer and a plain-English explanation for every question. Free, no login.
Q21Consider the process of NaCl dissolving in water. Which statements are true regarding the behavior of ions and physiological effects? I. Na⁺ is a cation and Cl⁻ is an anion. II. When NaCl dissolves, the concentration of ions in the solution decreases. III. The increase in Na⁺ concentration in cells may affect osmolarity. IV. Cl⁻ ions are expelled from cells to maintain balance. Process Description Dissolving NaCl dissociates to form Na⁺ and Cl⁻ in water Ion Type Na⁺ is a cation; Cl⁻ is an anion Effect Increases ionic concentration affecting osmolarity
✓ Correct answer: D. I and III
NaCl dissociates into Na⁺ and Cl⁻ ions in water. Na⁺ is a cation, and Cl⁻ is an anion. When NaCl dissolves, the ion concentration in solution increases. Increased intracellular Na⁺ can impact osmolarity, while Cl⁻ generally remains in solution to maintain charge balance.
Q22In human bodily fluids, which of the following ions is considered a cation? Ion Type Charge Example Ion Cation Positive Potassium (K+) Anion Negative Chloride (Cl−)
✓ Correct answer: C. Potassium (K+)
Potassium ions (K+) are positively charged, meaning they are cations. Chloride, phosphate, and bicarbonate ions are negatively charged, making them anions.
Q23Which of the following atoms is most likely to participate in an ionic bond with calcium, an atom with 2 valence electrons?
✓ Correct answer: C. Oxygen (6 valence electrons)
Calcium has 2 valence electrons and tends to lose them to achieve a stable electron configuration. Oxygen, having 6 valence electrons, is most likely to gain electrons to complete its valence shell, making it most likely to form an ionic bond with calcium.
Q24In the human body, electrolytes are crucial for nerve transmission and muscle contraction. Which ionic bond forms between two common electrolytes to create table salt?
✓ Correct answer: A. Sodium ion (Na⁺) and Chloride ion (Cl⁻)
Sodium ions (Na⁺) and chloride ions (Cl⁻) form an ionic bond to create sodium chloride (NaCl), commonly known as table salt. This bond is a typical example of how a positively charged ion (cation) and a negatively charged ion (anion) come together to form a stable compound.
Q25Refer to the following table on types of bonds in common molecules. Nutrient Element Type Electronegativity Difference Bond Type Water Oxygen and Hydrogen Small Carbon Dioxide Carbon and Oxygen Small Sodium Chloride Sodium and Chlorine Large Methane Carbon and Hydrogen Small What type of bond is present in methane (CH₄) based upon the electronegativity difference?
✓ Correct answer: B. Nonpolar covalent
Methane (CH₄) is composed of carbon and hydrogen, which have a minimal electronegativity difference. This results in a nonpolar covalent bond where electrons are shared equally.
Q26Given the following data on the solubility of different compounds in water, which are the factors that positively impact the solubility of ionic compounds? I. Interaction with water molecules due to partial charges II. Complete dissociation into ions III. Strong covalent bonds between atoms
✓ Correct answer: D. I and II
Ionic compounds dissolve well in water because water's polar nature can stabilize the ions formed upon dissociation. While I describes a characteristic of polar covalent compounds, ionic compounds fully dissociate in water (II), enhancing their solubility.
Q27Examine the list of different salts and their characteristics below. Based on the presence and magnitude of partial charges (Δ+ and Δ−), which compound is expected to be most soluble in water at physiological conditions (pH 7.4, 37°C)? Table of compounds: - Compound A: neutral covalent molecule, no significant partial charges (no Δ+ or Δ−). - Compound B: ionic/polar salt with pronounced partial charges (clear Δ+ on one end and clear Δ− on the other). - Compound C: weakly polar molecule with small partial charges (small Δ+ and Δ−). - Compound D: nonpolar, hydrophobic salt-like molecule with minimal charge separation.
✓ Correct answer: B. Compound B
Polar compounds with larger partial charges (greater Δ+ and Δ−) interact more strongly with water via ion-dipole and dipole-dipole interactions and therefore tend to be more soluble in water. Compound B has pronounced partial charges, so it should be the most soluble under physiological conditions.
Q28Analyze the following data on ion locations in blood plasma. Determine the likely transport mechanism for $$\text{Na}^+$$ ions based on their location and common transport processes. Ion Location in blood plasma Transport mechanism $$\text{Na}^+$$ In blood plasma Via ion channels $$\text{K}^+$$ Inside red blood cells Na-K pump $$\text{Ca}^{2+}$$ In blood plasma Calcium channels $$\text{Cl}^-$$ In blood plasma Chloride channels
✓ Correct answer: A. Via ion channels
Sodium ions ($$\text{Na}^+$$) are typically transported via specific ion channels that allow passage through the cell membrane due to their charge and size. Direct diffusion is unlikely for charged particles like ions, which require channel-mediated transport. ATP-powered pumps are more commonly associated with pumping ions against concentration gradients (e.g., Na-K pump), not facilitating diffusion in blood plasma. Active transport involving vesicles is a mechanism for larger molecules and not typically related to ion transport like it is with $$\text{Na}^+$$, $$\text{K}^+$$, $$\text{Ca}^{2+}$$, or $$\text{Cl}^-$$.
Q29Examine the following table of mineral components found in bone tissue. Identify the predominant type of bond that holds together the ionic compounds listed. Mineral Component Primary Ions Involved Bond Type Hydroxyapatite Calcium, Phosphate Carbonate Calcium, Carbon Fluoride Calcium
✓ Correct answer: D. Ionic Bond
The mineral components in bone tissue, such as hydroxyapatite, are primarily held together by ionic bonds. This is because these compounds involve metal ions, like calcium, and non-metal ions, such as phosphate or carbonate, that exhibit significant differences in electronegativity.
Q30Considering the unique properties of water, which property is heavily influenced by hydrogen bonds, and results in water having a higher boiling point than expected? Property Influence of Hydrogen Bonds Boiling point Surface tension Viscosity Density
✓ Correct answer: C. Boiling point
Hydrogen bonds significantly affect the boiling point of water, making it higher than expected for such a small molecular weight. The intermolecular attractions caused by hydrogen bonds require more energy (heat) to break as water transitions from liquid to gas.
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