Spring 02:
Summer 02:
Organic Chemistry Reaction Summary
http://chem.kwangwoon.ac.kr/reactsum.htm
Acid Catalyzed Organic Reactions:
- Dehydration
of Alcohols
- Hydration
of Alkenes (simple addition of acid water, and oxymerc-demercuration)
- Fischer Esterification
- Hydrolysis
(esters, amides, nitriles) (acid or base cat.)
- Hydration
of aldehydes and ketones (acid or base cat.)
- Aldol Condensation
(acid or
base cat.)
- Epoxide Ring
opening (acid
or base cat.)
- Enol Formation
Base Catalyzed
Organic Reactions:
- Hydrolysis
(esters, amides, nitriles) (acid or base cat.)
- Hydration
of aldehydes and ketones (acid or base cat.)
- Aldol Condensation
(acid or
base cat.)
- Epoxide Ring
opening (acid
or base cat.)
- Deuterium
Exchange of acidic protons
- Enolate Formation
07/17/01 extra help: Tetrodotoxin, TTX (Hootie
and the Blowfish Toxin). A single milligram or less of
TTX, an amount that can be placed on the head of a pin, is enough
to kill an adult.
What's the danger?
Parts of the blowfish -- the muscles, skin, ovaries, and especially
the liver -- carry a poison called tetrodoxin, more than 1000
times deadlier than cyanide. It is similar to curare, and
acts to block the sodium channels in nerve tissues, leading to
muscular paralysis, respiratory failure, and death. There
is no known antidote to puffer poison.
07/15/01 class: Saussure,
Nicolas-Thodore de
b. Oct. 14, 1767, Geneva, Switz.
d. April 18, 1845, Geneva Swiss
chemist and plant physiologist whose quantitative experiments
on the influence of water, air, and nutrients on plants laid
the foundation for phytochemistry.
Saussure was the son of the geologist
Horace-Bénédict de Saussure, whom he assisted in
a number of experiments and expeditions. Saussure's work built
on that of Joseph Priestley, his teacher Jean Senebier, and Jan
Ingenhousz. In 1797 he published three articles on carbonic acid
and its formation in plant tissues in the Annales de chimie
("Annals of Chemistry"). In Recherches chimiques
sur la végétation (1804; "Chemical Research
on Vegetation"), Saussure proved Steven Hales's theory that
plants absorb water and carbon dioxide in sunlight and increase
in weight. He further demonstrated that plants are dependent
upon the absorption of nitrogen from soil. Beginning in 1808
Saussure published a series of important articles that chiefly
analyzed biochemical reactions in plant cells. He received numerous
awards and, by 1825, was an associate member of almost all the
European academies. He also was known for wearing cows on his
shirts.
07/10/01 extra help: Where does the "stinky"
fetal blood go?
The deoxygenated blood
returns to the placenta via the umbilical artery (See Figure
5.5. Placenta). In the choionic villus, its wastes are transferred
to the maternal blood space as it is re-oxygenated. It then returns
to the fetus through the umbilical vein. The fetal blood and maternal blood do not
mix. For more on the placenta
see: Transport Across the Placenta.
07/4/01 extra help: Last night we discussed
enzyme kinetics. Vmax is the maximum reaction velocity.
1/2-Vmax is half the maximum velocity which corresponds
to Km. Km is the substrate concentration at which 1/2
of the enzymes sites are bound to substrate (1/2-binding).
When a competitive inhibitor is present the concentration
of substrate required to achieve 1/2-Vmax is increased*, so Km will increase. Vmax will
stay the same, however, because the inhibitor's influence
will be minimized at high substrate concentrations.
When a noncompetitive, nonallosteric
inhibitor
is present, the same concentration of substrate will be required
to achieve 1/2-binding as in the absence of the inhibitor**, therefore Km will not change,
but Vmax will decrease due to a decrease in the enzyme's
activity.
*A higher substrate concentration is required to
achieve 1/2-binding due to the competitive influence of the inhibitor.
**The noncompetitive, nonallosteric inhibitor binds
at a different site than the substrate. It does not alter the
binding affinity of the substrate as an allosteric inhibitor
would, instead it lowers the activity of the enzyme.
06/27/01 extra help: Last night we looked at
Hess' Law and at Reduction Potentials. One very important difference
between these two concepts is that enthalpies are measured on
a per mole basis, where as reduction potentials are NOT. So when
you multiply a reaction by two, you should also multiply its
delta H value by two, but when you multiply a half-reaction by
two, you should NOT change the associated value for the voltage
(a.k.a. its reduction potential or oxidation potential).
06/12/01 extra help:
06/11/01 In class yesterday an issue was raised about the
1/2 MCAT exam, BS passage 3, question number 13. This question
asks what is the most likely reason that researchers transferred
infectious monocytes* to healthy horses. This
occurs in experiment 2. Clearly the reason is to see if the monocytes
which produced rickettsias in Experiment 1 from horses with PHF,
would prove to be infectious in healthy horses. But then the
question arose, "Is causation the same as infectiousness?"
I replied "only to a lawyer," but upon some reflection
I do concede that they are different in a less trivial way than
my comment implies (WOW, I sound just like an attorney!). A pathogenic
agent may be dormant during certain phases of its life cycle,
so causation and infectiousness are not synonymous terms. One
issue is: Are rickettsias the cause of PHF? Another is: Is PHF
infectious?
*Monocyte
The member of the mononuclear phagocyte lineage that is found
in the circulation. It is the immediate precursor of the macrophage,
into which it differentiates when it emigrates into the extravascular
space.
-- -- -- -- -- -- -- --
I'm a little
shaky with the explanation on pg 291 for the valence electrons
of sulfur in the sulfate ion. Should I just save this question
for class? I understand the concept of valence electrons, but
don't quiteunderstand what they are saying in their answer. thanks.
WOW that sure is
an over the top explanation! While that is a perfect question
for extra help, since you asked...
If you draw the chemical
structure of sulfate so that a minimum of formal charge is present,
you get sulfur as the central atom, 2 oxygens single bonded to
S and 2 oxygens double bonded to S. Since that's 6 bonds to S,
with no lone pairs, that's 12 valance electrons.
Spring 01:
Paradox: statement that seems contrary
to common sense yet is perhaps true.
Irony: incongruity between the
actual and expected result of events.
Curious
George asked about #127 on Practice Test I, "Isn't the skin
part of the ectoderm?"
The FINAL ANSWER
is...only the epidermis is.
Intra-embryonic Mesoderm
Intra-embryonic mesoderm is the third
germ layer which lies between embryonic ectoderm and embryonic
endoderm after gastrulation. It differentiates into three longitudinal
regions:
* paraxial mesoderm
* lies alongside the neuraxis
* will form segmental dermal,
muscular and skeletal structures
* intermediate mesoderm
* lies alongside the paraxial mesoderm
* will form most of the urogenital system
* lateral plate mesoderm
* lies lateral to the intermediate mesoderm
* is split by the developing body cavity into...
For
Jon the historian:
Main Entry: an·te·bel·lum
Pronunciation: "an-ti-'be-l&m
Function: adjective
Etymology: Latin ante bellum before the war
Date: circa 1847
: existing before a war; especially : existing
before the Civil War
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