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BIOL 2600 Human Physiology, Fall 2016, Prof. Stark
Third Hourly Exam, Friday December 5, Short Answer
1. "Androgenic alopecia" ANSWER EITHER (1)Why is it not called
a sex-linked trait? OR (2) Why was it called a sex-limited trait?
1-sex linked means on the X chromosome, 2-limited to men
2. Obviously, a steroid hormone does not bind to a response element. How
does a steroid hormone affect a response element?
a steroid hormone binds a steroid hormone receptor and the receptor binds
the response element
3. "Seven-year-old boys and girls behave differently, and this is probably
due to circulating testosterone levels." Refute the last half of this
sentence and discuss whether and how testosterone may be responsible for
there is no testosterone in boys that age but there was neonatal testosterone
which had organizing effects on the brain
4. T4 (one of the thyroxine molecules) comes up to a cell's membrane in
the company of a carrier protein; eventually thyroxine binds a receptor
that binds a response element. Give another detail to complete the story
of how it activates transcription of a gene.
turns to T3, retinoic acid binds another receptor that binds an adjacent
5. You are studying mitochondrial DNA in humans. Was that inherited from
the father, the mother, or both?
only the mother
6. "PGI2 mediates antiplatelet aggregation." How does this information
lead to a common drug treatment?
people, mostly elderly, take aspirin to prevent heart attacks
7. If you have elective surgery coming up, why would you be told to refrain
from taking NSAIDS (non-steroidal anti-inflammatory drugs) a few weeks in
they are anticoagulants and you would bleed
8. What is the PSA test?
for prostate specific antigen, test for prostate cancer
9. "Then it implants into the endometrium." EITHER (1) name or
(2) describe what it is that implants.
blastocyst, ball of cells with inner cell mass, trophoblast and blastocyst
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. A sperm is just about to fertilize an "egg" but it has not
quite yet. Answer either (1) What is this prefertilization egg called? OR
(2) Where in the process of meiosis, is this "egg?"
secondary oocyte has finished first meiotic division but not second
12. Many women want to bear their children before the age of 40 because
of an increased likelihood of (what is the most famous disorder here)?
trisomy-21 (Downs syndrome)
13. Under the influence of a gene on the Y chromosome, "indifferent
gonads" turn into a structure that produces Mullerian Inhibiting Factor
(MIF) plus (what?).
the testes also produce testosterone
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 that site?
15. Macrophage: ANSWER EITHER (1) Why does the word end in "phage?"
OR (2) What type of white blood cell is it derived from?
1-it eats (phagocytoses) bacteria, 2-monocyte
16. Why, in the early days of AIDS, were hemopheliacs particularly susceptible?
blood banks were not safe, and clotting factor was produced from multiple
17. A naïve B cell is exposed to an antigen. Describe the constituents
of the clone of cells that develops from this cell.
plasma cells make antibody, memory cells preserve the information
18. 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.
19. 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
20. Independently, you develop two different antibodies to the same antigen
molecule. I contend that there is a vanishingly low possibility that these
antibodies are the same. Why would I say such a thing?
they are specific to any 5-15 amino acid subset of the entire protein
21. In the news: Why do you think they gave a blood product from an ebola
survivor to an ebola patient?
passive immunity from gamma globulin
22. "Class-2 MHC molecules are expressed on macrophages and B cells."
By contrast, where are class1 MHC molecules expressed?
lots of cells
23. "The Pacinian corpuscle has rapid adaptation." How does that
relate to its particular function?
that means it responds to vibration and is useful for active feeling (moving
your fingertips) touch
24. In the 1800's, Broca delineated a brain area critical for speech. How
did he do this?
after death, looked at brains of patients whose speech had been damaged
25. "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
26. Lemniscal system. ANSWER EITHER (1) Where is the tract in the spinal
cord? (2) Which side of the spinal cord is it in (relative to where the
receptor is)? OR (3) What is the function of this submodality?
1-dorsal columns, 2-same side (ipsilateral), 3-fine touch (as opposed to
27. You all have the protein coded for by the gene involved in Huntington's
disease. And yet you do not have Huntington's disease (hopefully). What
is the difference for people who do, in fact, have Huntington's disease?
they have more CAG repeats (coding for glutamine)
28. The basal nuclei collect information from all over the brain and send
it to (where?) to achieve better coordination of motor movements.
motor cortex (via thalamus)
29. Why would a lesion (an injury) halfway across the spinal cord cause
an ipsilateral loss of fine touch below the injury but a contralateral loss
of pain below the injury?
the decussation in the lemniscal system is in the medulla while the decussation
in the anterolateral system is at the site of entry to the spinal cord
30. Where is the first synapse in the taste projection?
at the base of the receptor cell
31. "cAMP acts as a ligand in olfactory receptors." Say something
to elaborate this point.
the G protein cascade has cAMP as the "second messenger" and cAMP
opens the channel in the cell membrane, and so this ligand acts on the channel
from inside the cell
32. The chemoreceptive part of the olfactory cell is in the nasal cavity.
Where is the synapse?
in the olfactory bulb (first cranial nerve) of the brain
33. There are 3 semicircular canals plus (name one other component) in the
34. The endolymph fluid in the cochlear duct (scala media which bathes the
stereocilia) is unusual (for an extracellular fluid) in that it contains
a high concentration of (what?)
35. 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
36. In terms of either what is in the membrane OR how an extracellular protein
assists, say how transduction in hair cells works.
a mechanoreceptive channel, tip links
37. One tuning fork clearly had a higher pitch than the other. How did you
know that they differed by only a few Hz?
you could hear just a few beats per second when listening to both simultaneously
38. There are four or five synapses in the auditory pathway. Where are the
terminals of the cells in the thalamus (that receive synaptic input from
"further down, the inferior colliculus)?
on the auditory part of the cerebral cortex
39. 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
40. In an eye exam, they check your eye pressure. If it is too high, answer
either (1) Which cells die? OR (2) Which portion of the eye does not drain
ganglion cells, aqueous humor (anterior chamber)
41. Fixating on an X with your right eye, there is a place off to the right
where you are blind. Reconcile that fun "blind spot" demonstration
with my statement that the optic nerve exits the eye on the nasal side.
off to the right means on the temporal visual field, and, because the image
is inverted, that is the nasal retinal field
42. "My optic bench features a mercury arc lamp and a grating monochromator."
How do I change the intensity of the visual stimulus?
put in neutral density filters where each 0.3 log units cuts the light in
43. Which portion of the nervous system connects to the iris to mediate
the constriction of the pupil elicited by a light stimulus?
parasympathetic, occulomotor nerve (#3), from ciliary ganglion
44. 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
45. Other than serving as the "black paint" that keeps light from
reflecting around the eye, state another function of the retinal pigment
phagocytose shed rod disks, chemical reactions to replenish 11-cis-retinal
46. Why would we use the term "tunnel vision" for the blindness
in retinitis pigmentosa?
rods in a circle around the point of fixation degenerate
47. Why are you unable to see ultraviolet light (while I can)?
the lens blocks UV, I had a lens removed
48. In phototransduction, the heterotrimeric G protein's alpha subunit activates
an enzyme. For EITHER Drosophila OR humans, what is that enzyme?
phospholipase C or cGMP" PDE
49. "Vitamin A is the chromophore of rhodopsin." We get this vitamin
A from what dietary precursor?
carotenoids like beta carotene
50. Say something about the garbage that accumulates in cells of the aging
called lipofuscin, autofluoresces yellow, in retinal pigment epithelium
cells, from shed photoreceptor tips
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last updated Nov. 28, 2016