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WorksheetsCoordination
Total questions: 15
Worksheet time: 11mins
Which of the following is NOT characteristics of electrical impulse?
Electrical impulse is an all or nothing event
During refractory period, neuron is not sensitive to another stimulus
Impulse transmission along the axon is slower than the one at synapse
Speed of impulse conduction depends on diameter of axon and the presence or absence of myelin sheath
In myelinated axon of mammals, depolarisation only occurs at
Nodes of Ranvier
Schwann cells
Myelin sheath
Oligodendrocytes
Which of the following represents positive feedback mechanism?
1
2
3
4
In which phase, does both, voltage gated sodium and potassium ions channels, are closed?
1
3
4
5
Which statement best describes the resting state of a neuron?
Neuron is polarised with more sodium ions outside the cell and more potassium ions inside the cell
Neuron is propagating the action potential along its axon
Neuron is repolarising as potassium ions diffuse out of the cell
Neuron is restoring the ionic conditions utilising the sodium-potassium pump
An action potential is caused by an influx of __________ ions into the cell.
Calcium
Potassium
Chloride
Sodium
Once the action potential has traveled along the sarcolemma, what structure takes the action potential into the interior of the muscle fibre?
Sarcoplasmic reticulum
Transverse tubule
Mitochondria
Sarcoplasm
What is the role of calcium ions during a synaptic transmission?
Generate action potential in postsynaptic membrane
Bind to the receptor of ligand gated sodium ion channels and causes depolarisation of postsynaptic membrane
Trigger the fusion of synaptic vesicles containing neurotransmitter to the presynaptic membrane
Involve in the reuptake of neurotransmitter into the synaptic knob
What generates a nerve impulse on the postsynaptic membrane?
Neurotransmitter being removed from the synaptic cleft
Neurotransmitter binds to the receptor protein of the ligand gated ion channels
Influx of sodium ions into the postsynaptic membrane through opened ligand gated ion channels
Influx of calcium ion into the presynaptic membrane
What two molecules are necessary for muscle contraction to occur?
Sodium and potassium ions
Calcium and sodium ions
Calcium ions and ATP
ATP and acetylcholine
The functional unit of muscle contraction is known as
Neuron
Nephron
Actin and myosin
Sarcomere
__________ and __________ are regulatory proteins bound to actin.
Troponin and myosin
Troponin and tropomyosin
Actin and myosin
Myosin and myoglobin
Which of the following is NOT true when muscle is fully contracted?
H zone disappears
A band remains the same
Sarcomere shortens
Length of actin and myosin filaments changes
What is a cross bridge?
Myosin head with high-energy configuration attaches to the exposed myosin binding sites on actin
ATPase catalyse the hydrolysis of ATP into ADP and inorganic phosphate
Calcium ion bind to troponin, the binding causes troponin to change shape
Myosin heads pull actin, the thin filament, toward the centre of the sarcomere
Which of the following is mechanism of action of cocaine?
It binds to the receptor of ligand gated ion channels on postsynaptic membrane and causes continuous depolarisation
Cocaine blocks the reuptake of dopamine by binding competitively with the dopamine reuptake transporter
It degrades the neurotransmitters before they could bind to the ligand gated ion channels on postsynaptic membrane
It interferes with impulse transmission along the axon
