Question 1

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

Accepted Answer

Water molecules form hydration spheres around ions and polar molecules, keeping them in solution.

Question 2

A patient is experiencing muscle cramps due to an electrolyte imbalance. Which of the following ions is most likely involved, and why are electrolytes important in body fluids?

Accepted Answer

Potassium (K+); electrolytes conduct electrical currents necessary for nerve impulses and muscle contraction.

Question 3

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms joined by strong bonds, while a compound consists of two or more atoms of different elements joined by strong or weak bonds.

Question 4

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes are protein catalysts that lower the activation energy of reactions without being changed or used up.

Question 5

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-4}$$ moles per liter. What is the pH of this solution, and is it acidic, neutral, or basic?

Accepted Answer

$$pH = 4$$, acidic

Question 6

Which of the following best describes the role of buffers in body fluids?

Accepted Answer

Buffers stabilize pH by neutralizing strong acids or bases, often involving a weak acid and its related salt.

Question 7

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

Accepted Answer

$$AH + BOH \rightarrow AB + H_2O$$

Question 8

A patient is diagnosed with a genetic disorder affecting the primary structure of a protein. Which level of protein structure is directly altered, and what does this level represent?

Accepted Answer

Primary structure; the sequence of amino acids along the polypeptide chain.

Question 9

Which of the following best explains why saturated fatty acids are solid at room temperature, while unsaturated fatty acids are liquid?

Accepted Answer

Saturated fatty acids have no double bonds, allowing them to pack closely together, while unsaturated fatty acids have one or more double bonds causing kinks that prevent tight packing.

Question 10

Which of the following statements about nucleic acids is correct?

Accepted Answer

DNA consists of two complementary strands held together by hydrogen bonds between nitrogenous bases.

Question 11

A scientist adds hydrochloric acid (HCl) to a beaker of water. What happens to the pH and why?

Accepted Answer

The pH decreases because HCl is an acid and increases the concentration of hydrogen ions ($$H^+).$$

Question 12

Which of the following best describes the difference between a strong acid and a weak acid in physiological solutions?

Accepted Answer

A strong acid dissociates completely in solution, while a weak acid only partially dissociates.

Question 13

Which of the following is a correct example of an exchange reaction?

Accepted Answer

$$AB + CD \rightarrow AD + CB$$

Question 14

Which of the following best explains why proteins can lose their function when exposed to high heat or extreme pH?

Accepted Answer

High heat or extreme pH causes denaturation, which changes the protein's shape and disrupts its function.

Question 15

Which of the following best describes the structure and function of phospholipids in the plasma membrane?

Accepted Answer

Phospholipids have hydrophilic heads and hydrophobic tails, forming a bilayer that separates the cell from its environment.

Question 16

A molecule of glucose ($$C_6H_{12}O_6$) is classified as which of the following?

Accepted Answer

A monosaccharide, which is a simple sugar and a monomer of carbohydrates.

Question 17

Which of the following best explains the importance of the carbonic acid-bicarbonate buffer system in human physiology?

Accepted Answer

It helps maintain blood pH within the narrow range necessary for proper enzyme function.

Question 18

Which of the following best describes the process of phosphorylation in high-energy compounds?

Accepted Answer

Phosphorylation is the process of adding a phosphate group to another molecule, producing a high-energy bond.

Question 19

A patient is found to have a mutation that prevents the formation of peptide bonds. Which macromolecule would be most directly affected?

Accepted Answer

Proteins, because peptide bonds link amino acids together.

Chemical Foundations of Anatomy & Physiology: Atoms, Elements, and Atomic Structure

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