Announcements:
The outline/study guide for the final will be available Friday (12/5) morning, online or from 9:30-10:00am in the 4th floor conference room of Bonner Hall (email me if you need directions)
A Thanksgiving Question:
Chickens, turkeys and other fowl are known to have white meat and dark meat. Ducks, especially wild ducks, tend to have more dark meat than either of those non-migrating land-dwellers. What is the difference between white meat and dark meat, and why is there a difference between species with different lifestyles? Hunters often say that it's bad to chase your game before you kill it, because it will taste bad. Explain how this is related to the white meat/dark meat topic.
Handouts:
• Jenny's outline for Midterm 1 (covers First and Second Week ONLY!) .doc format and HTML
• Jenny's outline for Midterm 2.doc format and HTML
NEW!!! (12/5/03) • Jenny's outline for the FINAL .doc format and HTML
• Quizzes Weeks 2,3,4 and 6 in .pdf
Just to clarify...
When RUBISCO catalyzes the joining of RuBP to O2, the product is two molecules of PHOSPHOGLYCOLATE. Sometimes it's hard to hear Dr. Schmidt well in WLH 2001, and I guess it sounded like "phospholycolate" when he said it. You won't find phospholycolate anywhere in your book, but you will find phosphoglycolate on p. 149.
I hear this was a good explanation of chromosome movement in meiosis, so I will share it with all of you:
Call this a chromosome: ----•--------
In your starting diploid cell, since it is diploid, there will be two homologous copies of our chromosome, one from each parent (m& p mean maternal and paternal):
----•-------- (m) ----•-------- (p) (G1 of interphase of your diploid cell)
Once it undergoes DNA synthesis, each of those homologous chromosomes has TWO sister chromatids (because that's what happens when you copy the chromosome)
===•====== (m) ===•====== (p) (after S phase of interphase of your diploid cell)
If you're going to go through meiosis, these two homologous chromosomes synapse (line up next to each other touching each other) at metaphase I.
===•====== (m) (sorry I can't draw them touching, but they do)
===•====== (p)
So the spindle apparatus, in my little picture, would come down from the top and up from the bottom, and each would grab a hold of one centromere, and at anaphase, the homologs would separate, so each daughter cell would have one of these:
===•====== (either m or p...this one has m)
Technically speaking, that makes them haploid now, because each only has one version, not two (not both m and p). However, they look like haploids in G2 (their chromosomes have two sister chromatids), not haploids in G1, so they still have to go through one more division. This thing:
===•====== lines up at the equatorial plate, and at anaphase II, the sister chromatids come apart, making two daughter cells, each with: ----•--------
The term "single-chromatid chromosomes," which I was using for explanatory purposes on Monday, is NOT a real term. When there's only one copy, you just call it "the chromosome," and after S phase when there's two copies, the "chromosome" then consists of two "sister chromatids." It's a terminology issue, and doesn't invalidate any of the chromosomal behavior I was discussing.
A few words on C4 and CAM photosynthesis:
"C4 plants" separate the C4 photosynthesis process from the Calvin Cycle by carrying on the C4 cycle in specialized cells called mesophyll cells and carrying on the Calvin Cycle in "bundle sheath" cells. The mesophyll cells export malate, the product of C4 photosynthesis, to the bundle sheath cells, where it is decarboxylated to make CO2 and pyruvate, raising the concentration of CO2 in the bundle sheath cell (thus forcing RUBISCO to do carbon fixation instead of photorespiration). "CAM plants" carry on C4 photosynthesis during the night, and store malate in the vacuole. When day comes and the heat and shortage of water start favoring photorespiration, the plant takes all that stored malate back out, releases the CO2, and makes RUBSICO fix carbon. C4 plants separate the two cycles spatially, CAM plants separate them temporally.
Some notes from Gradeless Quiz 1
- "Hydroxyl" is the name of the group, "alcohol" is a molecule with a hydroxyl on it. Example: Ethanol is an alcohol that has whose hydroxyl group can form hydrogen bonds with water.
- Peptide bonds form between amino acids forming a peptide chain (a dipeptide, a tripeptide, a polypeptide, etc.). Another type of condensation reaction we've learned about is the glycosidic bond between sugars.
- Be careful to keep your diagrams consistent! If you draw all your hydrogens in one case, don't use lines to represent hydrogens in another (in condensed bond line diagrams, a line drawn next to an atom means a methyl group!)
- The carbonyl group is a carbon double-bonded to an oxygen. It is an aldehyde if that double-bonded carbon is the terminal carbon in a chain; it is a ketone if that carbon has other carbons on either side.
- An exercise: Go to your local O-chem textbook and look up the structure of formaldehyde.