BIO 514 EXAM 1B LATEST UPDATED 2025 WITH COMPLETE SOLUTIONS
What three structures make up the triad of a muscle cell?
1 T-tubule & 2 terminal cisternea
Are are the six steps of excitation of a muscle cell?
1. Nerve signal opens voltage-gated Ca2+ channels in the motor nerve fiber.
2. Ca2+ triggers exocytosis of synaptic vesicles.
3. Acetylcholine is released into the synaptic cleft.
4. Acetylcholine binds to ligand-gated receptors opening cation channels.
5. End plate potential (EPP) is formed
6. Voltage change opens voltage-gated channels (action potential)
What are the six steps of the excitation-contraction coupling of a muscle cell?
1. Action potential spreads over the sarcolemma.
2. Voltage-gated channels open in T-tubules.
3. Calcium enters the sarcolemma reticulum.
4. Calcium binds to troponin.
5. Troponin-tropomyosin complex undergoes a conformational change.
6. Actin active sites become exposed for myosin binding.
What are the eight steps to contraction of a muscle cell?
1. Myosin head hydrolyzes ATP into ADP and Pi.
2. Energy from ATP activates the head.
,3. Head 'cocks' back.
4. Head binds to actin active site forming a cross- bridge.
5. Phosphate is released from the myosin head.
6. Powerstroke.
7. ADP is released.
8. Myosin head releases actin.
What enzyme is responsible for the relaxation of a muscle?
Acetylcholinesterase (removes acetylcholine from receptors)
What kind of transport is required for the relaxation of a muscle?
Active transport (via ATP)
The convergence of many presynaptic terminals onto one postsynaptic neuron.
Spacial summation
Neurotransmitters bind to what specific kind of channel?
Chemically-regulated.
A circular path of neurons synapsing with one after another.
Reverberating circuit
A specialized junction between two cells in which the electrical activity in one cell
will directly influence the electrical activity in another.
Synapse
What are the two different mechanisms (or types) of synapses?
, 1. Electrical Synapse
2. Chemical Synapse
What are the two characteristics of an electrical synapse?
1. The physical plasma membrane connection of pre-synaptic & post-synaptic cells
via gap junctions for communication
2. Occurs primarily in cardiac & smooth muscle cells
What are the two characteristics of a chemical synapse?
1. The transfer of neurotransmitters from pre-synaptic cells to post-synaptic cells
for communication
2. Occurs primarily in nervous system cells
What are the six steps in the mechanism of a chemical synapse?
1. An action potential reaches the axon terminal of a pre-synaptic cell.
2. Voltage changes in the axon terminal trigger the opening of voltage-gated Ca2+
channels.
3. Ca2+ rushes into the axon terminals & trigger exocytosis of synaptic vesicles.
4. Synaptic vesicles fuse to the plasma membrane of the axon terminal.
5. Neurotransmitters are released from synaptic vesicles & diffuse into the
synaptic cleft.
6. Neurotransmitters bind to highly specific ligand-gated post-synaptic receptors.
What specific kind of change in membrane potential does a chemical synapse
induce on a post-synaptic cell?
Graded potential (because there are no voltage-gated channels in the dendrites of
a post-synaptic cell)
What three structures make up the triad of a muscle cell?
1 T-tubule & 2 terminal cisternea
Are are the six steps of excitation of a muscle cell?
1. Nerve signal opens voltage-gated Ca2+ channels in the motor nerve fiber.
2. Ca2+ triggers exocytosis of synaptic vesicles.
3. Acetylcholine is released into the synaptic cleft.
4. Acetylcholine binds to ligand-gated receptors opening cation channels.
5. End plate potential (EPP) is formed
6. Voltage change opens voltage-gated channels (action potential)
What are the six steps of the excitation-contraction coupling of a muscle cell?
1. Action potential spreads over the sarcolemma.
2. Voltage-gated channels open in T-tubules.
3. Calcium enters the sarcolemma reticulum.
4. Calcium binds to troponin.
5. Troponin-tropomyosin complex undergoes a conformational change.
6. Actin active sites become exposed for myosin binding.
What are the eight steps to contraction of a muscle cell?
1. Myosin head hydrolyzes ATP into ADP and Pi.
2. Energy from ATP activates the head.
,3. Head 'cocks' back.
4. Head binds to actin active site forming a cross- bridge.
5. Phosphate is released from the myosin head.
6. Powerstroke.
7. ADP is released.
8. Myosin head releases actin.
What enzyme is responsible for the relaxation of a muscle?
Acetylcholinesterase (removes acetylcholine from receptors)
What kind of transport is required for the relaxation of a muscle?
Active transport (via ATP)
The convergence of many presynaptic terminals onto one postsynaptic neuron.
Spacial summation
Neurotransmitters bind to what specific kind of channel?
Chemically-regulated.
A circular path of neurons synapsing with one after another.
Reverberating circuit
A specialized junction between two cells in which the electrical activity in one cell
will directly influence the electrical activity in another.
Synapse
What are the two different mechanisms (or types) of synapses?
, 1. Electrical Synapse
2. Chemical Synapse
What are the two characteristics of an electrical synapse?
1. The physical plasma membrane connection of pre-synaptic & post-synaptic cells
via gap junctions for communication
2. Occurs primarily in cardiac & smooth muscle cells
What are the two characteristics of a chemical synapse?
1. The transfer of neurotransmitters from pre-synaptic cells to post-synaptic cells
for communication
2. Occurs primarily in nervous system cells
What are the six steps in the mechanism of a chemical synapse?
1. An action potential reaches the axon terminal of a pre-synaptic cell.
2. Voltage changes in the axon terminal trigger the opening of voltage-gated Ca2+
channels.
3. Ca2+ rushes into the axon terminals & trigger exocytosis of synaptic vesicles.
4. Synaptic vesicles fuse to the plasma membrane of the axon terminal.
5. Neurotransmitters are released from synaptic vesicles & diffuse into the
synaptic cleft.
6. Neurotransmitters bind to highly specific ligand-gated post-synaptic receptors.
What specific kind of change in membrane potential does a chemical synapse
induce on a post-synaptic cell?
Graded potential (because there are no voltage-gated channels in the dendrites of
a post-synaptic cell)
