1. In a rare syndrome, a chromosomally normal female can be masculinized
by androgens. Considering that she does not have testes, where did these
androgens come from?
2. The enzyme 5-alpha-reductase is thought to be involved in androgenic
alopecia. Answer either (1) What is androgenic alopecia? or (2) What product
of 5-alpha reductase might contribute to androgenic alopecia?
baldness in men, dihydrotestosterone
3. The hormone T4 comes up to a cell's plasmalemma in the company of a carrier
protein. Say something about what else is involved before that hormone might
activate a gene's transcription.
converts to T3, binds receptor protein, that protein binds DNA, in the company
of 9-cis retinoic acid bound to RXR receptor
4. Answer one of the following: COX-2 inhibitors were greeted with enthusiasm
by medical professionals and patients at first (why?) but eventually there
were problems (why?).
without also inhibiting COX1, there were fewer gastric problems, but, alas,
the incidence of heart attacks increased
5. Testes, prostate, bulbourethral gland (Cowper's gland). What gland that
is missing from that list contributes to semen?
6. I said "The likelihood of having two sperm cells with the same combination
of genes you got from your mother vs. your father in your whole life is
infinitesimal." State how this diversity is achieved,
not only is there a random selection of which centromere is chosen (that
comes to 2 to the 23 possibilities) but crossing over (recombination) exchanges
genes along the chromosome
7. Answer one of the following. (1) What is the status of the "egg,"
in terms of progress through the entire process of meiosis, at the time
of ovulation? or (2) What is the status of the "egg," in terms
of progress through the entire process of meiosis, at the time the sperm
is about to penetrate?
same answer for both. Through with meiosis I but not II (arrested at metaphase)
8. After implantation,...(answer ONE of the following) a peptide ( name
that peptide) sees to it that a steroid ( where is the steroid from?)
maintains the endometrium.
HCG, corpus luteum
9. "The IUD does not prevent fertilization!" Elaborate.
after fertilization and early development, it prevents implantation.
10. In 2006, while George W. Bush was President, the famous actor Michael
J. Fox, who has Parkinson's disease, came to Missouri to support McCaskill,
the democrat running for senate. Answer either (1) Why would he have been
so interested (in embryonic stem cell research)? or (2) Why has interest
in the issue of embryonic stem cell research decreased so much since then?
such stem cells might eventually be used in treatments to replace the degenerated
neurons but now embryos might not be needed since skin cells can be made
into pluripotent stem cells
11. About the time chorionic villi are present, what had been the inner
cell mass has further developed, and one portion is now called the embryo.
Answer either (1) Why might it be useful to biopsy the chorionic villi?
or (2) In addition to the endoderm and the mesoderm, what is the third layer
in that early embryo?
to test for chromosomal or genetic disorders, ectoderm
12. What happens if there is no Mullerian inhibiting factor?
uterus and uterine tubes are formed
13. Why was there a new "selection pressure" against hemopheliacs
coltting factor, prepared from blood of multiple donors, might have HIV
14. A neutrophil arrives at the site of the injury. Answer either (1) What
does it do when it gets there? or (2) What do they call the process of its
attraction to move to tht site?
15. Why would blood cells be expected to agglutinate for a type B transfusion
into a type A recipient?
the Y shaped antibody molecule can hold two red blood cells together.
16. There are some interesting differences in ABO blood groups vs. Rh factor
antibodies. Answer either (1) Why would there be a bad reaction to the first
type A transfusion into a B recipient? or (2) Why would an Rh- mother only
have to worry (a lot!) about her further pregnancies after she has born
an Rh+ baby?
there is already antibody, the IgG crosses the placent
17. In 1796, Jenner exposed people to cowpox to give them immunity to smallpox.
What did Lady Montague do 3/4 of a century earlier to make people immune
she exposed them to smallpox itself
18. A naive B cell is exposed to an antigen and develops into a clone of
plasma cells that produce antibodies plus (what other important type of
19. At and after birth, an infant has the mother's immunities. Describe
one of the two ways this happens with reference to the specific antibody
involved in the mechanism you are describing.
IgG through placenta then IgA from breast milk
20. "An enzyme at the site of injury converts a precursor into bradykinin."
What does this tell us about the somatosensory system?
nociceptors are actually chemoreceptors
21. A free nerve ending or an encapsulated touch receptor like a Pacinian
corpuscle that mediates fine touch has an axon that comes into the central
nervous system. Where does this cell have its synaptic termination?
way up in the medulla
22. How did they learn which parts of the body project to which parts of
the postcentral gyrus?
gently stimulate the gyrus in a patient under local anesthesia ahd ask where
(s)he feels a tingle
23. "If half of your spinal cord were lesioned, say as a result of
an accident, you would have an ipsilateral loss of sensation mediated by
the lemniscal system below the site of the injury." What is the situation
(side of the body relative to which half is cut) for pain and temperature
sensation below the site of the injury?
24. The corticospinal tract would be involved in arm and leg movements.
In what way is this situation different for the face?
25. In terms of the extrapyramidal motor system of the brain, answer either
(1) where does dopamine come from? or (2) Where dies dopamane go to?
substantia nigra, striatum
26. "The thalamus is a motor relay." How can that be true when,
in fact, the tract from the precentral gyrus to the spinal motor neuron
does not have a synapse in the thalamus?
basal ganglia and cerebellum feed back to postcentral gyrus through thalamus
27. What would happen to the coding sequence of the mutant allele for Huntington's
chorea from one generation to the next?
there would be more CAG's coding for more glutmines
28. Name (or give the number for) one of nerves that connect the taste receptors
to the brain.
vagus 10, glossopharyngial 9, mostly facial 7
29. A gustatory receptor sensitive to quinine has a G protein-coupled receptor;
the cascade results in calcium ions being released from an endoplasmic reticulum.
Why would an increase in cytoplasmic calcium ions be useful in gustatory
for release of synaptic transmitter vesicles
30. Monosodium glutamate affects which taste receptor primary?
31. The diagram of axons from olfactory receptors does not show connection
to the closest glomerulus. What characteristic of the olfactory receptor
determines which glomerulus it connects to?
ones that respond to the same primary pool to the same glomerulus
32. Approximately how many G protein coupled receptors are there for human
33. One tuning fork sounded higher than the other in our classroom demonstration.
How did we "calibrate" (in the classroom) how much they differ
by how many beats there were
34. In what way is the very low number (0.0002 dynes per square centimeter)
fundamental in human hearing?
the standard pressure (denominator) in the definition of dB
35. When the mechanoreceptive channel on an auditory receptor opens, potassium
ions come into the cell through that channel. What makes that unusual direction
the extracellular fluid is high in potassium ions
36. "Bekesy's Nobel prize winning research confirmed Helmholtz's place
theory." That is one way of looking at the finding. In what way did
Bekesy's work confirm Helmholtz's theory?
different frequencies preferentially vibrated different places on the basilar
membrane (though crudely)
37. Say something about tonotopic organization of sound on the cerebral
on the auditory cortex on the temporal lobe, different frequencies are represented
in different places
38. Glaucoma: answer either (1) What compartment does not drain properly
in this disorder? or (2) What is the mechanism of loss of vision (blindness)
[e.g. media lose their transparency, refractory error, etc].
aqueous humor (anterior chamber) ganglion cells (the ones that form the
optic nerve) degenerate
39. "A laser is used to destroy patches of the retina." Answer
either (1) Who might actually benefit from this procedure? or (2) Why would
the ophthalmologist avoid blasting the fovea with the laser?
a diabetic, fovea is too essential for high acuity color vision at the point
40. What kind of people would have the focussed image in front of the retina
instead of on the retina?
41. If the ciliary muscle is contracted, what happens to... (answer one
of these) (1) the suspensory ligaments, or (2) the shape of the lens, or
(3) your eyesight?
they become slack, it gets rounder, for near vision
42. "Eye care professionals dilate the pupil with belladona alkaloids."
Pretend this is all you know and then explain, on that basis, what output
from the parasympathetic nervous system does to the pupil.
drug blocks parasympathetic neuro-effector junction, so parasympathetic
must do opposite, constrict
43. "A single rod can 'see' one photon of light." How is it that
such a cell physiology piece of knowledge was first established on the basis
of ordinary people like you and me indicating whether or not they could
see various light stimuli?
psychophysics, careful calibrations, careful measurements, showed only 6-14
quanta absorbed over a 500 rod area
44. A cis to trans isomerization of what chromophore, (name that chromophore),
a component of a G protein coupled receptor, is the only thing light actually
does in visual transduction?
11-cis retinal (retinene) the aldehyde of vitamin A
45. I suggested that a gene duplication on the X chromosome could be used
to explain how the superfamily of G protein coupled receptors evolved. Which
two proteins are made by the two duplicated X chromosomal genes I am referring
the genes for red- and green-absorbing rhodopsins
46. Rhodopsin signals to a G protein and the G protein signals to what enzyme?
Answer for either the vertebrate or for the fruit fly. Hints: cGMP is involved
in the vertebrate rod and the fly utilizes the phosphoinositide signal transduction
a phosphodiesterase that converts cGMP
47. Coated pits and multivesicular bodies are involved in recycling of photoreceptive
membrane in fruit flies. By contrast, for vertebrate rods, an additional
type of cell is needed in the phagolysosomal system. What is this cell called?
retinal pigmen epithelium
48. Say something about visual sensitivity below 400 nm for either (1) a
person whose lens has been removed, or (2) the R7 cell in the fruit fly.
UV sensitivity is way higher, R7 is a UV receptor
49. For the fruit fly or for the rat, what happens when vitamin A "replacement
therapy" is attempted in a vitamin A deprived animal?
50. Our diets provide the precursor of vitamin A and also the yellow macular
pigments. Provide the name of one of the dimers of vitamin A that we eat.
beta carotene, lutein, zeaxanthin