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Saturday Study Session 2
Theme of the day:
Information Transfer
Session 2 – Cell signaling in the
Immune and Nervous systems
Question 1 Answer
C
Clue: depolarization =
Na+ in
Impulse generation
Na+
Na+
Na+
Na+
K+
K+
Rising phase of the action potential
Falling phase of the action potential
Na+
Na+
Membrane potential
(mV)
+50
0
–50
K+
Action
potential
–100
Threshold
Resting potential
Time
Depolarization
Na+
Na+
Extracellular fluid
Na+
Potassium
channel
Activation
gates
K+
Plasma membrane
Cytosol
Resting state
Undershoot
Sodium
channel
K+
Inactivation
gate
Question 2 Answer
D
Clue: Sum = add them
together
Summation = add them together
•
•
•
•
Start with -70 mV
IPSPs = -0.5 x 6 = -3.0
EPSPs = 0.5 X 2 = 1.0
Theerfore, -70mV + -3.0mV + 1.0mV = 72.0mV
Question 3 Answer
D
Clue: large distance in
very little time
Saltatory
Conduction
Schwann cell
Depolarized region
(node of Ranvier)
Cell body
Myelin
sheath
Axon
Question 4 Answer
B
Clue: chemical synapse=
neurotransmitter
Synapse at the axon
terminal
Presynaptic
cell
Postsynaptic cell
Synaptic vesicles
containing
neurotransmitter
Na+
K+
Presynaptic
membrane
Neurotransmitter
Postsynaptic
membrane
Ligandgated
ion channel
Voltage-gated
Ca2+ channel
Postsynaptic
membrane
Ca2+
Synaptic cleft
Ligand-gated
ion channels
Question 5 Answer
A
Clue: receptor in step 3
MHCs
Infected cell
Microbe
Antigen
fragment
Antigenpresenting
cell
Antigen
fragment
Class II MHC
molecule
Class I MHC
molecule
T cell
receptor
T cell
receptor
Cytotoxic T cell
Helper T cell
Question 6 Answer
B
Clue:
Math Grid In Answer
•
•
•
•
The correct answer is: 760 mm2
2 long sides with widths of 6mm = 6X 20 =
120 mm2 each
2 long sides with widths of 10mm = 10X 20 =
200 mm2 each
• 2 ends at 6 x10 = 60 mm2 each
• Total surface area =
• (120 x 2) +(200 X 2)+ (60 x 2) =
240 + 400 + 120 = 760 mm2
Short Free Response 1
(4 points possible… must have structure and function
together)
• Possible points awarded for:
• Discussion of the numerous dendrites covering a large area
and detecting a stimulus.
• Discussion of the cell body being the collecting point of
stimulus energies and containing the cell organelles.
• Discussion of the one dendrite being the exit point for the
nerve impulse on the way to the CNS or effector.
• Discussion of there being a gap (synapse) at the end of the
axon (axon terminal) where neurotransmitter is released.
Neuron structure
Short Free Response 2
(4 points possible)
• Possible points awarded for:
• Bark – outer protection like skin
• Tannins – Chemical defenses to make plant
taste bitter, like tears or saliva.
• Thorns – protection from herbivores
• Needles – cactus protection from animals