BIOL 103 Foundations of Cellular and
Molecular Biology Exam Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. Which statement best describes the cell theory?
A. All organisms are composed of tissues.
B. Cells arise spontaneously from nonliving matter.
C. All living organisms are composed of one or more cells, and cells are
the basic units of life.
D. Only multicellular organisms contain cells.
Rationale: Cell theory establishes that the cell is the fundamental
structural and functional unit of life. It also states that all living
organisms consist of one or more cells and that new cells arise from
pre-existing cells. The theory does not claim that organisms must be
multicellular or that cells arise spontaneously.
2. Which structure is present in both prokaryotic and eukaryotic
cells?
,A. Nucleus
B. Mitochondrion
C. Golgi apparatus
D. Ribosome
Rationale: Ribosomes are found in both prokaryotic and eukaryotic
cells and are responsible for protein synthesis. Prokaryotes lack
membrane-bound organelles such as nuclei, mitochondria, and Golgi
apparatuses.
3. What is the primary function of the plasma membrane?
A. Synthesizing proteins
B. Producing ATP
C. Storing genetic information
D. Regulating movement of substances into and out of the cell
Rationale: The plasma membrane forms a selectively permeable
boundary around the cell. Its phospholipid bilayer and associated
proteins regulate the movement of ions, molecules, and other
substances while also participating in cell signaling and recognition.
4. Which component forms the basic structural framework of the
plasma membrane?
,A. Cellulose
B. Glycogen
C. Phospholipid bilayer
D. Peptidoglycan
Rationale: Biological membranes are primarily composed of a
phospholipid bilayer. Phospholipids have hydrophilic heads that
interact with water and hydrophobic tails that face inward, creating a
selective barrier.
5. What property of phospholipids causes them to spontaneously
form bilayers in an aqueous environment?
A. They are entirely hydrophobic.
B. They are entirely hydrophilic.
C. They contain both hydrophilic and hydrophobic regions.
D. They contain covalently bonded carbohydrates.
Rationale: Phospholipids are amphipathic molecules. Their hydrophilic
heads interact with water, while their hydrophobic tails avoid water.
This arrangement drives the spontaneous formation of bilayers.
6. Which organelle is primarily responsible for producing ATP
through aerobic cellular respiration?
, A. Lysosome
B. Nucleus
C. Golgi apparatus
D. Mitochondrion
Rationale: Mitochondria are the primary sites of aerobic cellular
respiration in eukaryotic cells. They generate most cellular ATP
through the citric acid cycle, electron transport chain, and oxidative
phosphorylation.
7. Which organelle contains most of a eukaryotic cell's genetic
material?
A. Ribosome
B. Lysosome
C. Nucleus
D. Golgi apparatus
Rationale: The nucleus contains the majority of the cell's DNA
organized into chromosomes. The DNA provides instructions for
producing RNA and proteins that regulate cellular structure and
function.
8. What is the primary function of ribosomes?
Molecular Biology Exam Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. Which statement best describes the cell theory?
A. All organisms are composed of tissues.
B. Cells arise spontaneously from nonliving matter.
C. All living organisms are composed of one or more cells, and cells are
the basic units of life.
D. Only multicellular organisms contain cells.
Rationale: Cell theory establishes that the cell is the fundamental
structural and functional unit of life. It also states that all living
organisms consist of one or more cells and that new cells arise from
pre-existing cells. The theory does not claim that organisms must be
multicellular or that cells arise spontaneously.
2. Which structure is present in both prokaryotic and eukaryotic
cells?
,A. Nucleus
B. Mitochondrion
C. Golgi apparatus
D. Ribosome
Rationale: Ribosomes are found in both prokaryotic and eukaryotic
cells and are responsible for protein synthesis. Prokaryotes lack
membrane-bound organelles such as nuclei, mitochondria, and Golgi
apparatuses.
3. What is the primary function of the plasma membrane?
A. Synthesizing proteins
B. Producing ATP
C. Storing genetic information
D. Regulating movement of substances into and out of the cell
Rationale: The plasma membrane forms a selectively permeable
boundary around the cell. Its phospholipid bilayer and associated
proteins regulate the movement of ions, molecules, and other
substances while also participating in cell signaling and recognition.
4. Which component forms the basic structural framework of the
plasma membrane?
,A. Cellulose
B. Glycogen
C. Phospholipid bilayer
D. Peptidoglycan
Rationale: Biological membranes are primarily composed of a
phospholipid bilayer. Phospholipids have hydrophilic heads that
interact with water and hydrophobic tails that face inward, creating a
selective barrier.
5. What property of phospholipids causes them to spontaneously
form bilayers in an aqueous environment?
A. They are entirely hydrophobic.
B. They are entirely hydrophilic.
C. They contain both hydrophilic and hydrophobic regions.
D. They contain covalently bonded carbohydrates.
Rationale: Phospholipids are amphipathic molecules. Their hydrophilic
heads interact with water, while their hydrophobic tails avoid water.
This arrangement drives the spontaneous formation of bilayers.
6. Which organelle is primarily responsible for producing ATP
through aerobic cellular respiration?
, A. Lysosome
B. Nucleus
C. Golgi apparatus
D. Mitochondrion
Rationale: Mitochondria are the primary sites of aerobic cellular
respiration in eukaryotic cells. They generate most cellular ATP
through the citric acid cycle, electron transport chain, and oxidative
phosphorylation.
7. Which organelle contains most of a eukaryotic cell's genetic
material?
A. Ribosome
B. Lysosome
C. Nucleus
D. Golgi apparatus
Rationale: The nucleus contains the majority of the cell's DNA
organized into chromosomes. The DNA provides instructions for
producing RNA and proteins that regulate cellular structure and
function.
8. What is the primary function of ribosomes?
