BIO 201 EXAM 3 – A&P I – ACTUAL QUESTIONS & ANSWERS
(STRAIGHTERLINE) (UPDATED PDF)
THIS PRACTICE EXAM IS MODELED AFTER THE STRAIGHTERLINE BIO 201
(ANATOMY & PHYSIOLOGY I) EXAM 3 CURRICULUM. IT COVERS THE
MUSCULAR SYSTEM (PHYSIOLOGY AND ANATOMY) AND THE NERVOUS SYSTEM
(FUNDAMENTALS, CNS, PNS, AND AUTONOMIC NERVOUS SYSTEM).
Table of Contents
1. Section 1: Muscle Tissue and Physiology (Questions 1-25)
2. Section 2: Nervous Tissue and Fundamentals (Questions 26-50)
3. Section 3: The Central Nervous System (Questions 51-75)
4. Section 4: The Peripheral and Autonomic Nervous Systems (Questions 76-100)
Section 1: Muscle Tissue and Physiology
1. What is the functional unit of a skeletal muscle fiber?
• Answer: Sarcomere.
• Rationale: The sarcomere is the repeating unit between two Z-discs where the actual
contraction (shortening) occurs via the sliding filament mechanism.
2. Which protein wraps around actin and prevents myosin from binding during relaxation?
• Answer: Tropomyosin.
• Rationale: Tropomyosin blocks the active sites on actin; it is only moved when calcium
binds to troponin.
3. What is the role of Calcium ions (
𝐶𝑎2+
) in muscle contraction?
• Answer: It binds to troponin, causing a conformational change in tropomyosin.
• Rationale: Binding to troponin moves the tropomyosin "shield," allowing myosin heads
to attach to actin.
4. The "All-or-None" principle states that:
, • Answer: A muscle fiber will contract fully or not at all in response to a threshold
stimulus.
• Rationale: If a stimulus reaches the threshold, the entire fiber depolarizes and contracts;
there is no "partial" contraction of a single fiber.
5. Which type of muscle is characterized by being multinucleated and striated?
• Answer: Skeletal muscle.
• Rationale: Skeletal muscles are formed by fused cells (syncytium) and have organized
sarcomeres (striations).
6. What neurotransmitter is released at the Neuromuscular Junction (NMJ)?
• Answer: Acetylcholine (ACh).
• Rationale: ACh travels across the synaptic cleft to bind to receptors on the motor end
plate of the sarcolemma.
7. In a relaxed muscle, where is most of the calcium stored?
• Answer: Sarcoplasmic Reticulum (SR).
• Rationale: The SR acts as a specialized smooth ER that stores and releases calcium for
contraction.
8. What happens during the "Power Stroke" of muscle contraction?
• Answer: The myosin head pivots and pulls the actin filament toward the M-line.
• Rationale: This occurs after the release of ADP and inorganic phosphate from the
myosin head.
9. Which molecule provides the energy needed to "re-cock" the myosin head?
• Answer: ATP.
• Rationale: ATP hydrolysis (ATP to ADP + P) provides the energy to return the myosin
head to its high-energy state.
10. What is a motor unit?
• Answer: One motor neuron and all the muscle fibers it innervates.
• Rationale: When the neuron fires, all fibers in that specific unit contract simultaneously.
11. Which type of contraction results in a change in muscle length while tension remains
constant?
• Answer: Isotonic contraction.
(STRAIGHTERLINE) (UPDATED PDF)
THIS PRACTICE EXAM IS MODELED AFTER THE STRAIGHTERLINE BIO 201
(ANATOMY & PHYSIOLOGY I) EXAM 3 CURRICULUM. IT COVERS THE
MUSCULAR SYSTEM (PHYSIOLOGY AND ANATOMY) AND THE NERVOUS SYSTEM
(FUNDAMENTALS, CNS, PNS, AND AUTONOMIC NERVOUS SYSTEM).
Table of Contents
1. Section 1: Muscle Tissue and Physiology (Questions 1-25)
2. Section 2: Nervous Tissue and Fundamentals (Questions 26-50)
3. Section 3: The Central Nervous System (Questions 51-75)
4. Section 4: The Peripheral and Autonomic Nervous Systems (Questions 76-100)
Section 1: Muscle Tissue and Physiology
1. What is the functional unit of a skeletal muscle fiber?
• Answer: Sarcomere.
• Rationale: The sarcomere is the repeating unit between two Z-discs where the actual
contraction (shortening) occurs via the sliding filament mechanism.
2. Which protein wraps around actin and prevents myosin from binding during relaxation?
• Answer: Tropomyosin.
• Rationale: Tropomyosin blocks the active sites on actin; it is only moved when calcium
binds to troponin.
3. What is the role of Calcium ions (
𝐶𝑎2+
) in muscle contraction?
• Answer: It binds to troponin, causing a conformational change in tropomyosin.
• Rationale: Binding to troponin moves the tropomyosin "shield," allowing myosin heads
to attach to actin.
4. The "All-or-None" principle states that:
, • Answer: A muscle fiber will contract fully or not at all in response to a threshold
stimulus.
• Rationale: If a stimulus reaches the threshold, the entire fiber depolarizes and contracts;
there is no "partial" contraction of a single fiber.
5. Which type of muscle is characterized by being multinucleated and striated?
• Answer: Skeletal muscle.
• Rationale: Skeletal muscles are formed by fused cells (syncytium) and have organized
sarcomeres (striations).
6. What neurotransmitter is released at the Neuromuscular Junction (NMJ)?
• Answer: Acetylcholine (ACh).
• Rationale: ACh travels across the synaptic cleft to bind to receptors on the motor end
plate of the sarcolemma.
7. In a relaxed muscle, where is most of the calcium stored?
• Answer: Sarcoplasmic Reticulum (SR).
• Rationale: The SR acts as a specialized smooth ER that stores and releases calcium for
contraction.
8. What happens during the "Power Stroke" of muscle contraction?
• Answer: The myosin head pivots and pulls the actin filament toward the M-line.
• Rationale: This occurs after the release of ADP and inorganic phosphate from the
myosin head.
9. Which molecule provides the energy needed to "re-cock" the myosin head?
• Answer: ATP.
• Rationale: ATP hydrolysis (ATP to ADP + P) provides the energy to return the myosin
head to its high-energy state.
10. What is a motor unit?
• Answer: One motor neuron and all the muscle fibers it innervates.
• Rationale: When the neuron fires, all fibers in that specific unit contract simultaneously.
11. Which type of contraction results in a change in muscle length while tension remains
constant?
• Answer: Isotonic contraction.
