Mastering Cell Biology 2026–2027: The Ultimate 100-Question Practice Exam with Detailed Answer Rationales

Cell Biology – Comprehensive 100-Question
Practice Exam

EXAM OVERVIEW
Cell biology is the study of the structure, function, and behavior of cells—
the fundamental units of life. This exam covers the organization of
prokaryotic and eukaryotic cells, membrane structure and transport,
organelles and their functions, the cytoskeleton, cell signaling, the cell
cycle, and cellular metabolism.


SECTION 1: Cell Theory & Prokaryotic vs. Eukaryotic Cells
Q1. Cell theory states that:
• A) All living things are made of cells
• B) Cells are the basic unit of life
• C) All cells arise from pre-existing cells
• D) All of the above
Answer: D – Cell theory has three main tenets: all living organisms are
composed of one or more cells, the cell is the basic unit of life, and all cells
arise from pre-existing cells.


Q2. Prokaryotic cells differ from eukaryotic cells in that prokaryotic
cells:
• A) Have a nucleus
• B) Lack membrane-bound organelles
• C) Have membrane-bound organelles
• D) Are always multicellular

,Answer: B – Prokaryotic cells lack a true nucleus and membrane-bound
organelles. Eukaryotic cells have a nucleus and membrane-bound
organelles.


Q3. Which of the following is a characteristic of eukaryotic cells but
NOT prokaryotic cells?
• A) Ribosomes
• B) Plasma membrane
• C) Mitochondria
• D) DNA
Answer: C – Mitochondria are membrane-bound organelles found only in
eukaryotic cells. Prokaryotes have ribosomes, plasma membranes, and
DNA but lack mitochondria.


Q4. The genetic material of a prokaryotic cell is located in the:
• A) Nucleus
• B) Nucleoid region
• C) Mitochondria
• D) Golgi apparatus
Answer: B – Prokaryotic cells have a nucleoid region where the circular
DNA is located. They lack a membrane-bound nucleus.


Q5. Which domain includes organisms that have membrane-bound
organelles?
• A) Bacteria
• B) Archaea
• C) Eukarya

, • D) Both A and B
Answer: C – Eukarya includes all eukaryotic organisms with membrane-
bound organelles. Bacteria and Archaea are prokaryotic domains.


Q6. Which of the following is NOT a type of eukaryotic cell?
• A) Animal cell
• B) Plant cell
• C) Bacterial cell
• D) Fungal cell
Answer: C – Bacterial cells are prokaryotic. Animal, plant, and fungal cells
are eukaryotic.


SECTION 2: Organelles & Their Functions
Q7. The organelle that is the "powerhouse" of the cell and produces
ATP is the:
• A) Ribosome
• B) Golgi apparatus
• C) Mitochondrion
• D) Lysosome
Answer: C – Mitochondria are the site of cellular respiration and ATP
(energy) production. They have a double membrane.


Q8. Which organelle is responsible for protein synthesis?
• A) Nucleus
• B) Ribosome
• C) Golgi apparatus

, • D) Lysosome
Answer: B – Ribosomes are the sites of protein synthesis (translation). They
are found free in the cytoplasm or attached to rough endoplasmic
reticulum.


Q9. The organelle that modifies, sorts, and packages proteins for
secretion is the:
• A) Nucleus
• B) Rough ER
• C) Golgi apparatus
• D) Lysosome
Answer: C – The Golgi apparatus modifies, sorts, and packages proteins
and lipids for secretion or delivery to other organelles.


Q10. Lysosomes contain:
• A) ATP
• B) Digestive enzymes
• C) DNA
• D) RNA
Answer: B – Lysosomes are membrane-bound organelles containing
digestive (hydrolytic) enzymes for intracellular digestion of waste,
pathogens, and damaged organelles.


Q11. The nucleus of a cell contains:
• A) Ribosomes and mitochondria
• B) DNA and the nucleolus
• C) Lysosomes and peroxisomes