1. It's cold and you have "goose bumps" on your forearm. Relate
that to homeostasis for temperature regulation.
if you were a mammal with more fur, that would fluff up your fur for better
insulation and less heat loss
2. Why might you feel particularly cold when you come out of the swimming
pool soaking wet?
it removes a lot of heat from your body as liquid water evaporates
3. ACTH - - ANSWER EITHER (1) What gland does it stimulate? OR (2) What
does that gland release in response?
adrenal cortex, cortisol
4. It was argued that considerably less quantity of hypothalamic hormones
were needed to stimulate the anterior pituitary than hormone quantities
from glands throughout the body like the thyroid. Why?
the portal system delivers without dilution by the whole blood volume
5. If there were not enough iodine in the diet, explain how (and in what
direction) that would affect the level of thyroid stimulating hormone from
low iodine would lead to low thyroxine (T3 and T4, i.e. thyroid hormone)
and the lower negative feedback to the pituitary would increase TSH
6. Explain how a membrane transport worked to convert red blood cells into
red blood cell "ghosts"
when Gorter and Grendel showed, in 1925, that there was enough lipid in
a membrane to make two layers.
osmosis brought water in until the cell burst and hemoglobin and carbonic
anydrase were spilled out leaving only membranes
7. Say something about why the movement of glucose across the membrane is
called facilitated diffusion.
diffusion because it is passive (not requiring energy), facilitated because
the GLUT transporter is needed
8. How is it that a protein such as rhodopsin can reside in a membrane whose
interior is so hydrophobic?
its alpha helices are mostly hydrophobic amino acids
9. How did we visualize radioactively labeled phospholipids that had been
separated on a TLC plate?
by exposing photographic film (autoradiography)
10. "Homeostasis of calcium ions in the blood stream is very important."
Name one of the three hormones dedicated to this regulation.
parathormone, calcitonin and vitamin D
11. What is the body's natural ligand for the nicotinic receptor?
12. What is the significance of a coated vesicle?
it is used for receptor mediated endocytosis (pinocytosis), uses the protein
clathrin to make them look coated
13. Why might some synaptic excitation to a neuron's cell body and dendrites
not trigger an action potential at the axon hillock?
especially if there is inhibitory input, the net excitation might not be
14. Obviously, potassium ions WOULD flow down their concentration gradient
through a potassium channel. What is it about the Nernst equation that says
they SHOULD not?
the equillbrium assumption works out to say that electrical and chemical
gradients are equal and opposite
15. Two resistors in series on one side of a Wheatstone bridge might be
called a "voltage divider." Why?
voltage arises from a battery or from current flowing through a resistor,
and when there are two it ought to be IR1 + IR2
16. Curves that are referred to as "exponential" describe voltage
as a function of time. What property of membranes and circuits create these
delays in charging and discharging?
17. When Ohm's law is plotted with current on the Y axis, what is the slope
of the line?
conductance, g, in Siemens
18. What is the only thing that was shown with Cole and Curtis's work with
the Wheatstone bridge?
resistance goes down when the action potential goes by
19. Draw or describe a sensory neuron in the dorsal root ganglion.
has its cell body in the ganglion while the axon goes past into the spinal
20. "An action potential depolarizes the membrane ahead of it to threshold."
What is it about the space constant that relates to invertebrates having
space constant increases with the square root of the radius
21. How do the cells that myelinate axons differ in the central vs. the
peripheral nervous systems?
cns oligodendroglia myelinate a few axons while pns Schwann cells myelinate
22. How does experimental autoimmune encephalitis relate to myelin?
eae is a model for multiple sclerosis
23. What happens to the resistance of the postsynaptic membrane during an
goes down since potassium and chloride conductances increase
24. "Calcium ions are important for synaptic vesicle release."
ANSWER EITHER (1) How did calcium ions come to reside inside the presynaptic
membrane? OR (2) What do these calcium ions bind to for vesicle release?
through a voltage-gated calcium channel, synaptotagmin (also calmodulin
would be acceptable)
25. An action potential arrives at the axon's terminal. What does not happen
in the case of poisoning with Clostridium botulinum?
vesicles are not released
26. One type of receptor for acetylcholine is ionotropic, a ligand-gated
channel, the nicotinic receptor. What is the other type?
metabotropic, G protein-coupled receptor, muscarinic
27. How are melanin and dopamine related?
both have l-DOPA as a precursor, substantia nigra is dark because of melanin
and produces dopamine
28. What is the function of that place inside the brain called, alternatively,
putamen plus caudate, striatum, basal ganglia, or extrapyramidal system?
smoothen out (coordinate) voluntary motor movements
29. Give ONE step in the cascade between the binding of the hormone epinephrine
to a receptor and the production of glucose from glycogen.
activate G protein, activation of adenylate cyclase, production of cAMP,
activation of protein kinase A, activation of phosphorylase kinase, activation
30. ANSWER EITHER (1) For what ailment would you use an inhaler with the
beta-2 adrenergic agonist, terbutaline? OR (2) What does it do to bronchioles?
asthma, dilates them
31. A portion of the parasympathetic output comes from the sacral portion
of the spinal cord. What part of the central nervous system is the source
for the rest of the parasympathetic output?
32. Why would atropine have the effect it has on gastrointestinal motility?
blocking muscarinic cholinergic transmission, decreasing the rest and digest
parasympathetic output, would slow peristalsis
33. The sympathetic nervous system increases cardiac output by increasing
contraction strength (stroke volume) and (what?).
duh heart rate
34. Under what circumstances would a physician prescribe an inhibitor for
the phosphodiesterase that acts on cyclic GMP?
for erectile dysfunction
35. What is the unit called, along the myofibril, from one z-disk to the
36. Which muscle protein is affected by Duchenne muscular dystrophy?
37. When ATP comes into the previously empty binding pocket on the myosin
head group, what happens?
the binding of actin and myosin is terminated
38. Why, in his Nobel prize winning work, did Sir Bernard Katz decrease
the extracellular calcium in the neighborhood of the end plate?
to decrease vesicle release
39. CHOOSE ONE Under what circumstances would you be given (1) an acetylcholinesterase
inhibitor OR (2) a paralytic?
myasthenia gravis, to relax muscle for surgery
40. What TWO locations are there calcium channels in a striated muscle cell?
t-tubules and sarcoplasmic reticulum
41. What is glycogenolysis?
production of glucose from its polymer (glycogen) in muscle and liver
42. What modification must be made so that smooth muscle myosin can form
cross bridges with actin?
myosin light chain must be phosphorylated
43. When two amino acids are joined in a peptide bond, it is called dehydration
synthesis. What is it called when the two amino acids are broken apart?
44. When a fatty acid has a few double bonds, why is it called "polyunsaturated?"
it is not saturated with as many hydrogens as it would be with single bonds
45. Using hemoglobin as an example, what is the quaternary structure of
two alpha and two beta subunits linked together
46. What do humans do to get rid of the nitrogen generated if amino acids
are used for calories?
turn it to urea
47. "Glycolysis, 9 steps yielding two molecules of pyruvic acid from
one molecule of glucose, looks the same in aerobic vs anaerobic metabolism."
Then what is the difference in anaerobic conditions?
pyruvic acid is converted to lactic acid
48. "Most of the ATP is not generated in glycolysis plus the Krebs
cycle." Then where, in the metabolic pathway, is it generated?
oxidative phosphorylation and electron transport
49. Under the influence of insulin, how can there be a rapid increase in
the amount of glucose that can be transported into muscle and liver cells?
the GLUT4 transporters are at the ready in vesicles and moved to the plasmalemma
50. "The insulin receptor is called a 'receptor tyrosine kinase.'"
Why is the word "tyrosine" in this expression?
the enzyme phosphorynates the tyrosine residue (amino acid)
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