BIOL 251 Module 2 Exam: Cell Biology & Chemistry | Organelles, Mitosis & ATP Production Module 2: Chemistry & The Cell QUESTIONS AND ANSWERS | 2026 Review| PDF

BIOL 251 Module 2 Exam: Cell Biology & Chemistry | Organelles, Mitosis
& ATP Production Module 2: Chemistry & The Cell QUESTIONS AND
ANSWERS | 2026 Review| PDF


Part 1: Chemical Foundations
1. Which subatomic particle carries a negative charge and orbits the nucleus?
 A) Proton

 B) Neutron

 C) Electron

 D) Isotope

Explanation: Electrons are responsible for chemical bonding. Protons (positive) and
neutrons (neutral) stay in the nucleus.
2. An atom that has gained or lost an electron and now carries an electrical
charge is called a(n):
 A) Molecule

 B) Ion

 C) Isotope

 D) Element

Explanation: Ions are crucial for nerve impulses (e.g.,


,


). A positive ion is a cation; a negative one is an anion.
3. Which type of bond involves the "sharing" of electrons between atoms?
 A) Ionic bond

 B) Covalent bond

 C) Hydrogen bond

, D) Peptide bond

Explanation: Covalent bonds are the strongest bonds in the body, forming the
backbone of organic molecules like DNA and proteins.
4. Water is a "polar" molecule. This means:
 A) It freezes at 0°C.

 B) It has an uneven distribution of charge (slightly positive/negative ends).

 C) It does not mix with salt.

 D) It is an organic compound.

Explanation: Polarity allows water to be the "universal solvent," dissolving nutrients
and transport gases in the blood.
5. On the pH scale, a solution with a pH of 9 is considered:
 A) Acidic

 B) Neutral

 C) Basic (Alkaline)

 D) Buffered

Explanation: The pH scale runs from 0-14. 7 is neutral, below 7 is acidic, and above 7
is basic.
6. Which organic macromolecule is the body's "primary source of cellular fuel"?
 A) Lipids

 B) Carbohydrates (Glucose)

 C) Proteins

 D) Nucleic Acids

Explanation: Carbohydrates are broken down into glucose, which the mitochondria use
to produce ATP.
7. "Triglycerides" belong to which class of macromolecules?
 A) Carbohydrates

 B) Lipids

,  C) Proteins

 D) Nucleic Acids

Explanation: Lipids (fats) provide long-term energy storage, insulation, and protection
for organs.
8. Amino acids are the "building blocks" of which macromolecule?
 A) DNA

 B) Glycogen

 C) Proteins

 D) Cholesterol

Explanation: Proteins perform almost all functional roles in the body, acting as
enzymes, transport channels, and structural supports.
9. What is the primary function of "Enzymes"?
 A) To store genetic information.

 B) To speed up chemical reactions (biological catalysts).

 C) To provide waterproof barriers for cells.

 D) To act as a source of backup energy.

Explanation: Enzymes lower the activation energy required for reactions, allowing life-
sustaining processes to occur at body temperature.
10. Which nitrogenous base is found in RNA but NOT in DNA?
 A) Adenine

 B) Thymine

 C) Uracil

 D) Guanine

Explanation: RNA uses Uracil, whereas DNA uses Thymine to pair with Adenine.


Part 2: Cell Biology & Organelles (Questions 11–25)