BIO 225 Exam 3 Questions with Correct Answers Latest Update 2025/2026

BIO 225 Exam 3 Questions with Correct Answers Latest Update 2025/2026 a, c - Answers Which types of muscles have myogenic activity? a. cardiac muscle b. skeletal muscle c. smooth muscle b. ligand-gated ion channel - Answers Nicotinic acetylcholine receptors are... a. voltage-gated ion channels b. ligand-gated ion channels c. metabotropic receptors a. sarcoma - Answers Which of the following is NOT a part of a muscle cell? a. sarcoma b. sarcolemma c. sarcoplasmic reticulum d. sarcoplasm acetylcholine - Answers What neurotransmitter is released by motor neurons? smooth muscle - Answers What kind of muscle is being described: - mononucleated - lacking striations - spindle shaped - involuntary - neurogenic or myogenic - circular and longitudinal muscle layers cardiac muscle - Answers What kind of muscle is being described: - branch-like structure - one or two nuclei per cell - striations - myogenic - involuntary skeletal muscle - Answers What kind of muscle is being described? - organized in a tubular structure - neurogenic - striations - voluntary - multinucleated Type 1/slow twitch muscle fibers - Answers What type of muscle fiber is primarily used for endurance activities such as long-distance running? c. chromosome segregation - Answers In which of the following cellular processes are actin filaments NOT directly involved? a. cytokinesis b. vesicle transport c. chromosome segregation d. power stroke H-zone - Answers At which zone of the sarcomere is there NO overlapping of the myosin? This zone "disappears" when contraction occurs. in the sarcoplasmic reticulum (SERCA) AND in the sarcolemma (L type pump) - Answers In a relaxed myofiber, where are the Calcium pumps responsible for keeping intracellular Calcium low located? 1. elasticity 2. contractility 3. extensibility 4. excitability - Answers What are the four characteristics of muscle fibers we discussed? False; length of actin will not change to initiate contraction - Answers True or False: Actin filaments polymerize and depolymerize to cause muscle contractions. troponin - Answers What is the regulatory protein that binds actin? actin - Answers What are the thin filaments of the sarcomere composed of? capping proteins - Answers Stabilize actin filaments by binding to (+) or (-) end of actin. capZ - Answers Capping protein that binds to the (+) end of actin. tropomodulin - Answers Capping protein that binds to the (-) end of actin. true - Answers True or False: The myosin-binding site on actin is also bound by tropomyosin. white fibers - Answers Are red or white fibers utilized in fast-twitch muscle fibers? red fibers - Answers What kind of fiber is predominantly used in aerobic respiration? red fibers - Answers Utilized in slow twitch (type 1) muscle fibers; are rich in mitochondria and have high levels of myoglobin; aerobic respiration white fibers - Answers utilized in fast twitch (type 2) muscle fibers; anaerobic respiration when the thick filament butts up against the Z-disk - Answers When is the minimum sarcomere length for most muscles achieved? z-disk to another z-disk - Answers The length of one sarcomere in a muscle cell can be characterized by the distance between _________ to another _________. t-tubules - Answers Action potentials can be conducted into the muscle along invaginations of the sarcolemma, called the _______________. True - Answers True or False: protofilaments must form a sheet before they roll into a microtubule myosin and actin-cross bridge cycling - Answers What process would result from a change from low to high intracellular Calcium in a myofiber? acetylcholine - Answers Motor neurons release _________ into the neuromuscular synapse, which may generate depolarization at the motor end plate. troponin - Answers What thin filament protein directly binds to Calcium? the sarcoplasmic reticulum AND the extracellular fluid - Answers When intracellular Calcium levels rise in an excited myofiber, where does the Calcium come from b. myosin - Answers Thick filaments of the muscle cell contain which of the following proteins? a. tropomyosin b. myosin c. troponin d. all of the above the head region - Answers What region of myosin filaments attach to actin binding site? Grey matter - Answers Type of tissue found in the central nervous system that has a dulled appearance and contains dendrites, cell bodies, and unmyelinated axons white matter - Answers Type of tissue found in the central nervous system that has a shiny, bright appearance and is primarily composed of myelinated axons False; the brain and spinal chord - Answers True or False: Grey matter is only found in the brain. False; inner portion of spinal chord - Answers True or False: Grey matter is found on the outer edge of the spinal cord. White matter - Answers What kind of tissue is found on the outer edges of the spinal cord? the motor division - Answers What does the efferent branch of the nervous system consist of? short, long - Answers In the sympathetic nervous system, The pre-ganglionic neuron is ________ in length and post-ganglionic neuron is _______ in length.