ESTUDYR
BIOL 109 FINAL EXAM QUESTIONS AND ANSWERS
RATIONALES 2025/2026
Homeostasis is best defined as:
A. Rapid change in body systems
B. Random fluctuations in physiology
C. Maintenance of a stable internal environment.
D. Permanent change to match the environment
Rationale: Homeostasis = keeping internal conditions within narrow limits.
Which brain region primarily regulates homeostasis (temperature, hunger, thirst)?
A. Cerebellum
B. Hippocampus
C. Hypothalamus
D. Medulla oblongata
Rationale: Hypothalamus integrates autonomic and endocrine responses to maintain set
points.
The scientific method does NOT include which step?
A. Observation
B. Hypothesis formation
C. Telepathy
D. Experimentation and conclusion
Rationale: Scientific method is empirical and testable; telepathy is not a method step.
Controlled studies are characterized by:
A. Changing all variables at once
B. No control group
C. Controlling all variables except the independent variable
D. No hypothesis
Rationale: Controls isolate the effect of the independent variable.
An experimental protocol is:
A. A random idea
B. A step-by-step plan for conducting an experiment
C. Always secret
D. A statistical test only
Rationale: Protocols detail procedures to ensure reproducibility.
,ESTUDYR
Normal arterial blood pH range is approximately:
A. 6.0–6.8
B. 8.0–9.0
C. 7.35–7.45
D. 5.0–5.5
Rationale: Physiological arterial pH is tightly buffered around 7.4.
Osmosis describes movement of:
A. Ions through channels only
B. Solutes from low to high concentration
C. Water across a selectively permeable membrane
D. Gases only
Rationale: Osmosis is passive water diffusion driven by solute gradients.
Diffusion is:
A. Active transport using ATP
B. Movement of molecules from high to low concentration
C. Only for water
D. Vesicle mediated
Rationale: Diffusion relies on random molecular motion down gradients.
Passive transport requires:
A. ATP hydrolysis
B. Energy from sunlight
C. No cellular energy (moves down gradient)
D. Ribosomes
Rationale: Passive transport (diffusion, facilitated diffusion) is energy-free.
Active transport is:
A. Movement down gradient only
B. Movement against a concentration gradient using energy (ATP)
C. Always via gap junctions
D. Only in plants
Rationale: Active transport uses pumps or transporters to move solutes uphill.
A red blood cell placed in a hypertonic solution will:
A. Swell and burst
B. Remain unchanged
C. Shrink (crenate)
, ESTUDYR
D. Become vesicular
Rationale: Hypertonic external solution draws water out of cells.
A red blood cell in hypotonic solution will:
A. Shrink
B. Remain same
C. Swell and may lyse (burst)
D. Produce ATP faster
Rationale: Water enters cell in hypotonic medium causing swelling.
A red blood cell in isotonic solution will:
A. Shrink
B. Swell
C. Remain unchanged
D. Divide
Rationale: Isotonic means equal solute concentration; no net water movement.
Koch’s postulates are used to:
A. Cure diseases directly
B. Prove a specific microorganism causes a specific disease
C. Measure pH of blood
D. Sequence genomes
Rationale: Koch established criteria linking pathogens to disease.
Epithelial cells are classified by:
A. DNA sequence only
B. Shape (squamous/cuboidal/columnar) and layers (simple/stratified)
C. Motility only
D. Presence of chloroplasts
Rationale: Classic epithelial classification uses shape & layering.
The plasma membrane is characterized as:
A. A carbohydrate lattice
B. Protein only
C. Phospholipid bilayer with embedded proteins; selectively permeable
D. Rigid and impermeable
Rationale: Membrane fluid mosaic: lipids + proteins control transport.
Golgi apparatus primary function:
A. ATP production
B. DNA replication
BIOL 109 FINAL EXAM QUESTIONS AND ANSWERS
RATIONALES 2025/2026
Homeostasis is best defined as:
A. Rapid change in body systems
B. Random fluctuations in physiology
C. Maintenance of a stable internal environment.
D. Permanent change to match the environment
Rationale: Homeostasis = keeping internal conditions within narrow limits.
Which brain region primarily regulates homeostasis (temperature, hunger, thirst)?
A. Cerebellum
B. Hippocampus
C. Hypothalamus
D. Medulla oblongata
Rationale: Hypothalamus integrates autonomic and endocrine responses to maintain set
points.
The scientific method does NOT include which step?
A. Observation
B. Hypothesis formation
C. Telepathy
D. Experimentation and conclusion
Rationale: Scientific method is empirical and testable; telepathy is not a method step.
Controlled studies are characterized by:
A. Changing all variables at once
B. No control group
C. Controlling all variables except the independent variable
D. No hypothesis
Rationale: Controls isolate the effect of the independent variable.
An experimental protocol is:
A. A random idea
B. A step-by-step plan for conducting an experiment
C. Always secret
D. A statistical test only
Rationale: Protocols detail procedures to ensure reproducibility.
,ESTUDYR
Normal arterial blood pH range is approximately:
A. 6.0–6.8
B. 8.0–9.0
C. 7.35–7.45
D. 5.0–5.5
Rationale: Physiological arterial pH is tightly buffered around 7.4.
Osmosis describes movement of:
A. Ions through channels only
B. Solutes from low to high concentration
C. Water across a selectively permeable membrane
D. Gases only
Rationale: Osmosis is passive water diffusion driven by solute gradients.
Diffusion is:
A. Active transport using ATP
B. Movement of molecules from high to low concentration
C. Only for water
D. Vesicle mediated
Rationale: Diffusion relies on random molecular motion down gradients.
Passive transport requires:
A. ATP hydrolysis
B. Energy from sunlight
C. No cellular energy (moves down gradient)
D. Ribosomes
Rationale: Passive transport (diffusion, facilitated diffusion) is energy-free.
Active transport is:
A. Movement down gradient only
B. Movement against a concentration gradient using energy (ATP)
C. Always via gap junctions
D. Only in plants
Rationale: Active transport uses pumps or transporters to move solutes uphill.
A red blood cell placed in a hypertonic solution will:
A. Swell and burst
B. Remain unchanged
C. Shrink (crenate)
, ESTUDYR
D. Become vesicular
Rationale: Hypertonic external solution draws water out of cells.
A red blood cell in hypotonic solution will:
A. Shrink
B. Remain same
C. Swell and may lyse (burst)
D. Produce ATP faster
Rationale: Water enters cell in hypotonic medium causing swelling.
A red blood cell in isotonic solution will:
A. Shrink
B. Swell
C. Remain unchanged
D. Divide
Rationale: Isotonic means equal solute concentration; no net water movement.
Koch’s postulates are used to:
A. Cure diseases directly
B. Prove a specific microorganism causes a specific disease
C. Measure pH of blood
D. Sequence genomes
Rationale: Koch established criteria linking pathogens to disease.
Epithelial cells are classified by:
A. DNA sequence only
B. Shape (squamous/cuboidal/columnar) and layers (simple/stratified)
C. Motility only
D. Presence of chloroplasts
Rationale: Classic epithelial classification uses shape & layering.
The plasma membrane is characterized as:
A. A carbohydrate lattice
B. Protein only
C. Phospholipid bilayer with embedded proteins; selectively permeable
D. Rigid and impermeable
Rationale: Membrane fluid mosaic: lipids + proteins control transport.
Golgi apparatus primary function:
A. ATP production
B. DNA replication
