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BIO 201 RIO SALADO EXAM 1/ BIO 2O1 ANATOMY AND PHYSIOLOGY
NEWEST 2026 ACTUAL EXAM COMPLETE 160 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+ (BRAND NEW VERSION!)
Q1. Which organelle is responsible for producing most of a eukaryotic cell’s ATP?
A. Golgi apparatus
B. Lysosome
C. Mitochondrion
D. Ribosome
Answer: C. Mitochondrion
Explanation: Mitochondria perform oxidative phosphorylation in the inner
membrane (electron transport chain + ATP synthase) and produce most ATP in
aerobic cells.
Q2. Which tissue type lines body cavities and surfaces, often forming glands?
A. Connective tissue
B. Epithelial tissue
C. Muscle tissue
D. Nervous tissue
Answer: B. Epithelial tissue
Explanation: Epithelia cover surfaces and line cavities, form glandular tissue,
have little extracellular matrix, and show polarity (apical/basal surfaces).
Q3. Which bone cell type is primarily responsible for bone resorption (breaking
down bone matrix)?
A. Osteoblast
B. Osteocyte
C. Osteoclast
D. Chondrocyte
Answer: C. Osteoclast
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Explanation: Osteoclasts are large, multinucleated cells that resorb bone by
secreting acids and proteolytic enzymes. Osteoblasts build bone; osteocytes are
embedded mature bone cells.
Q4. During a muscle contraction, which filament slides past the other causing
sarcomere shortening?
A. Thick filaments slide past thick filaments
B. Thin filaments slide past thick filaments
C. Thick filaments slide past thin filaments
D. Only titin changes length
Answer: B. Thin filaments slide past thick filaments
Explanation: In the sliding filament model, actin (thin) filaments slide toward the
M line past myosin (thick) filaments, shortening the sarcomere.
Q5. Which structure of a neuron typically receives incoming signals?
A. Axon hillock
B. Axon terminal
C. Dendrites
D. Schwann cell
Answer: C. Dendrites
Explanation: Dendrites are branched processes that receive synaptic input. The
axon hillock integrates inputs; axon terminals release neurotransmitters.
Q6. Which hormone increases blood glucose by stimulating glycogenolysis and
gluconeogenesis?
A. Insulin
B. Glucagon
C. Aldosterone
D. Leptin
Answer: B. Glucagon
Explanation: Glucagon (from pancreatic alpha cells) raises blood glucose by
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promoting glycogen breakdown and formation of glucose from noncarbohydrate
sources. Insulin lowers glucose.
Q7. The primary pacemaker of the heart is the:
A. Atrioventricular (AV) node
B. Purkinje fibers
C. Sinoatrial (SA) node
D. Bundle of His
Answer: C. Sinoatrial (SA) node
Explanation: The SA node in the right atrium initiates normal rhythmic impulses
(fastest intrinsic rate), setting heart rhythm.
Q8. Which blood vessel layer contains smooth muscle and elastic fibers and is
primarily responsible for vasoconstriction/vasodilation?
A. Tunica intima
B. Tunica media
C. Tunica externa (adventitia)
D. Endothelium
Answer: B. Tunica media
Explanation: Tunica media is the middle layer containing smooth muscle and
elastic tissue; it controls vessel diameter. Intima includes endothelium; externa is
connective tissue.
Q9. Gas exchange in the lungs occurs primarily across which structure?
A. Terminal bronchiole
B. Alveolar duct
C. Alveolar-capillary (respiratory) membrane
D. Tracheal mucosa
Answer: C. Alveolar-capillary (respiratory) membrane
Explanation: Oxygen and CO₂ diffuse across the thin alveolar–capillary
membrane (type I alveolar cells + capillary endothelium + fused basement
membranes).
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Q10. Which kidney structure is the initial site of blood filtration?
A. Proximal tubule
B. Loop of Henle
C. Glomerulus within Bowman's capsule
D. Collecting duct
Answer: C. Glomerulus within Bowman's capsule
Explanation: The glomerulus is a capillary tuft where plasma is filtered into
Bowman's space; filtrate then enters the proximal tubule.
Q11. Which of the following best describes negative feedback?
A. Response increases the original stimulus
B. Response decreases the original stimulus
C. The system runs until positive feedback stops it
D. It only occurs in thermoregulation
Answer: B. Response decreases the original stimulus
Explanation: Negative feedback reduces deviations from a set point (e.g., insulin
release lowering blood glucose). Positive feedback amplifies change.
Q12. Which enzyme begins digestion of proteins in the stomach?
A. Pepsin (pepsinogen activated)
B. Lipase
C. Amylase
D. Trypsin
Answer: A. Pepsin (pepsinogen activated)
Explanation: Chief cells secrete pepsinogen; HCl activates it to pepsin, which
starts protein digestion. Trypsin functions in small intestine.
Q13. An action potential threshold in most neurons is approximately:
A. 0 mV
B. -70 mV
C. -55 mV
BIO 201 RIO SALADO EXAM 1/ BIO 2O1 ANATOMY AND PHYSIOLOGY
NEWEST 2026 ACTUAL EXAM COMPLETE 160 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+ (BRAND NEW VERSION!)
Q1. Which organelle is responsible for producing most of a eukaryotic cell’s ATP?
A. Golgi apparatus
B. Lysosome
C. Mitochondrion
D. Ribosome
Answer: C. Mitochondrion
Explanation: Mitochondria perform oxidative phosphorylation in the inner
membrane (electron transport chain + ATP synthase) and produce most ATP in
aerobic cells.
Q2. Which tissue type lines body cavities and surfaces, often forming glands?
A. Connective tissue
B. Epithelial tissue
C. Muscle tissue
D. Nervous tissue
Answer: B. Epithelial tissue
Explanation: Epithelia cover surfaces and line cavities, form glandular tissue,
have little extracellular matrix, and show polarity (apical/basal surfaces).
Q3. Which bone cell type is primarily responsible for bone resorption (breaking
down bone matrix)?
A. Osteoblast
B. Osteocyte
C. Osteoclast
D. Chondrocyte
Answer: C. Osteoclast
,2 | Page
Explanation: Osteoclasts are large, multinucleated cells that resorb bone by
secreting acids and proteolytic enzymes. Osteoblasts build bone; osteocytes are
embedded mature bone cells.
Q4. During a muscle contraction, which filament slides past the other causing
sarcomere shortening?
A. Thick filaments slide past thick filaments
B. Thin filaments slide past thick filaments
C. Thick filaments slide past thin filaments
D. Only titin changes length
Answer: B. Thin filaments slide past thick filaments
Explanation: In the sliding filament model, actin (thin) filaments slide toward the
M line past myosin (thick) filaments, shortening the sarcomere.
Q5. Which structure of a neuron typically receives incoming signals?
A. Axon hillock
B. Axon terminal
C. Dendrites
D. Schwann cell
Answer: C. Dendrites
Explanation: Dendrites are branched processes that receive synaptic input. The
axon hillock integrates inputs; axon terminals release neurotransmitters.
Q6. Which hormone increases blood glucose by stimulating glycogenolysis and
gluconeogenesis?
A. Insulin
B. Glucagon
C. Aldosterone
D. Leptin
Answer: B. Glucagon
Explanation: Glucagon (from pancreatic alpha cells) raises blood glucose by
,3 | Page
promoting glycogen breakdown and formation of glucose from noncarbohydrate
sources. Insulin lowers glucose.
Q7. The primary pacemaker of the heart is the:
A. Atrioventricular (AV) node
B. Purkinje fibers
C. Sinoatrial (SA) node
D. Bundle of His
Answer: C. Sinoatrial (SA) node
Explanation: The SA node in the right atrium initiates normal rhythmic impulses
(fastest intrinsic rate), setting heart rhythm.
Q8. Which blood vessel layer contains smooth muscle and elastic fibers and is
primarily responsible for vasoconstriction/vasodilation?
A. Tunica intima
B. Tunica media
C. Tunica externa (adventitia)
D. Endothelium
Answer: B. Tunica media
Explanation: Tunica media is the middle layer containing smooth muscle and
elastic tissue; it controls vessel diameter. Intima includes endothelium; externa is
connective tissue.
Q9. Gas exchange in the lungs occurs primarily across which structure?
A. Terminal bronchiole
B. Alveolar duct
C. Alveolar-capillary (respiratory) membrane
D. Tracheal mucosa
Answer: C. Alveolar-capillary (respiratory) membrane
Explanation: Oxygen and CO₂ diffuse across the thin alveolar–capillary
membrane (type I alveolar cells + capillary endothelium + fused basement
membranes).
, 4 | Page
Q10. Which kidney structure is the initial site of blood filtration?
A. Proximal tubule
B. Loop of Henle
C. Glomerulus within Bowman's capsule
D. Collecting duct
Answer: C. Glomerulus within Bowman's capsule
Explanation: The glomerulus is a capillary tuft where plasma is filtered into
Bowman's space; filtrate then enters the proximal tubule.
Q11. Which of the following best describes negative feedback?
A. Response increases the original stimulus
B. Response decreases the original stimulus
C. The system runs until positive feedback stops it
D. It only occurs in thermoregulation
Answer: B. Response decreases the original stimulus
Explanation: Negative feedback reduces deviations from a set point (e.g., insulin
release lowering blood glucose). Positive feedback amplifies change.
Q12. Which enzyme begins digestion of proteins in the stomach?
A. Pepsin (pepsinogen activated)
B. Lipase
C. Amylase
D. Trypsin
Answer: A. Pepsin (pepsinogen activated)
Explanation: Chief cells secrete pepsinogen; HCl activates it to pepsin, which
starts protein digestion. Trypsin functions in small intestine.
Q13. An action potential threshold in most neurons is approximately:
A. 0 mV
B. -70 mV
C. -55 mV
