Rules of the Day
4-20-2026
Click here for a copy of the lectures notes I wrote in class
Click here for a copy of the first handouts I used in class today
1.Corn starch is a cheap polymer of alpha-D-glucose that is converted by enzymes into a mixture of D-fructose and D-glucose, intended to mimic the composition of bee honey because of its sweetmess.
2. Both RNA and DNA have aromatic bases attached to carbohydrates via a glycosidic bond.
3. Lipids are biological molecules that are not soluble in water. Fatty acids, triglycerides, phospolipids, steroids and protaglandins are all lipids. Triglycerides are triesters of fatty acids with glycerol and are fats and oils, phospholipids make up membranes that are held together by the hydrophobic effect (maximizing hydrogen bonds between water molecules), steroids are rigid scaffolds for highly specific hormones molecules and prostaglandins are local signaling molecules, and the target of non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin, motrin and tylenol.
4. Many syntheses are carried out with a starting material reversibly attached to beads. This has the advantage of allowing exchange of reagents and isolation of products by simple filtration. This process can be automated! Mind officially blown! An efficient coupling strategy has been worked out for the solid phase synthesis of the phosphodiester bonds of DNA and RNA on glass beads by machine. You can order these on-line, they show up overnight by Fed-ex the next day!
5. Mother Nature does chemistry like chemists do! To make fatty acids, mammals use enzymes that carry out Claisen reactions with thioesters, using acetyl-CoA and malonyl-CoA derived from glucose, followed by reduction of the beta-ketone to an alcohol, dehydration to an alkene and reduction of the alkene. The take home lesson is here, perhaps the most important of the semester is that THE CHEMISTRY OF BIOLOGICAL SYSTEMS RESEMBLES THE CHEMISTRY WE HAVE LEARNED. YOU ARE NOW PREPARED TO CRUSH BIOCHEM!
Homework:
No more reading assignments this semester!!
Many students have difficulty understanding how to think about "equivalents", how to balance certain equations like the Claisen condensation, what do we mean by H3O+ and knowing when to use hydroxide versus ethoxide. Here are some short videos to help you with any of these: How to think about "Equivalents" when using base in enolate reactions (7:17 minutes) Correct video for How to think about "Equivalents" when using base in enolate reactions (3:29 minutes) How to balance a Claisen reaction equation (5:06 minutes) What do we mean by H3O+ (2:52 minutes) When to use NaOH vs. NaOEt (7:35 minutes)There is no daily more daily quizes!
When you are ready you can work on a practice homework that will help you prepare for the final. You will not turn it in. Click here for the questions and click here for the answers.
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