Question 1

Which subatomic particle is responsible for the positive charge of an atom's nucleus and helps determine the atomic number of an element?

Accepted Answer

Proton

Question 2

A neutral atom of carbon has 6 protons, 6 neutrons, and 6 electrons. What is the atomic number and mass number of this atom?

Accepted Answer

Atomic number: 6, Mass number: 12

Question 3

Which element is the most abundant in the human body by weight and is essential for respiration in its gaseous form?

Accepted Answer

Oxygen

Question 4

If an atom has an unfilled outermost energy level, what is its likely chemical behavior?

Accepted Answer

It readily reacts or combines with other atoms to gain, lose, or share electrons.

Question 5

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 6

A sodium atom (Na) loses one electron to become a sodium ion (Na⁺). What type of bond will it most likely form with a chloride ion (Cl⁻)?

Accepted Answer

Ionic bond

Question 7

Which of the following molecules is both a molecule and a compound?

Accepted Answer

$$H_2O$$

Question 8

What is the molecular weight of water ($$H_2O) $$given the atomic weights: $$H = 1$$, $$O = 16$$?

Accepted Answer

$$18$$

Question 9

Which property of water allows it to dissolve ionic compounds such as sodium chloride ($$NaCl$$)?

Accepted Answer

Polarity

Question 10

A solution has a pH of 5. What is the concentration of hydrogen ions ($$[H^+]) $$compared to a solution with pH 7?

Accepted Answer

100 times higher

Question 11

Which of the following is a strong acid that dissociates completely in water?

Accepted Answer

Hydrochloric acid ($$HCl)$$

Question 12

Which type of chemical reaction is represented by the following equation: $$AB + CD \rightarrow AD + CB$$?

Accepted Answer

Exchange reaction

Question 13

What is the primary function of carbohydrates in the human body?

Accepted Answer

Energy source

Question 14

Which type of lipid is a major component of cell membranes and has both hydrophilic and hydrophobic regions?

Accepted Answer

Phospholipid

Question 15

A protein loses its shape and function due to high temperature or extreme pH. What is this process called?

Accepted Answer

Denaturation

Question 16

Which of the following best describes the structure of DNA?

Accepted Answer

Double-stranded with thymine

Question 17

What is the role of enzymes in chemical reactions within the cell?

Accepted Answer

They lower the activation energy and speed up reactions.

Question 18

Which of the following is a buffer system important for maintaining blood pH in humans?

Accepted Answer

Sodium bicarbonate ($$NaHCO_3)$$

Question 19

Which of the following statements about ATP is correct?

Accepted Answer

ATP is formed by adding a phosphate group to ADP.

Question 20

A patient has a blood pH of 7.1. Which condition does this indicate, and what is the likely effect on hydrogen ion concentration?

Accepted Answer

Acidosis; increased $$[H^+]$$

The Chemical Level of Organization: Foundations for Anatomy & Physiology

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