This exam focuses on the recent blockbuster movie “IT” based on the novel by Stephen King. “It” is the name given to a mysterious interdimensional, shape shifting entity that, every 27 years, awakes and feeds on children. It can shape shift to take on the form of the fears of It’s prey. As fanciful as this story appears, it is actually a documentary based on true events. In fact, I have been receiving funding from the town of Derry (below which It lives) to study the primary form of It, which is the clown named Pennywise. If the biochemistry of Pennywise is better understood it may be possible to create a means to control this evil creature. In addition to the research funding from Derry, I have received a federal grant from the governmental agency known as the Department Of Evil Creatures That Are Featured In Novels That Are Thought To Be Fiction, But Are Actually True (DOECTAFINTATTBFBAAT). The town of Derry collected a considerable amount of tissue and blood from Pennywise. Although there are some very numerous similarities between the biochemistry of Pennywise and that of humans, there are also some striking differences. I have collected much data and will need your help in interpreting the some of this data and making sense of the complex biochemistry.
Answer the following questions. YOU MUST HANDWRITE OUT ANY ANSWER AND STRUCTURE!!!!!!
As I studied the tissue, was able to determine that Pennywise has all of the same amino acids as humans (with same pKa values), but also had one not observed any known organisms on earth. I named it pennywisine (B, Pen) and it has two sidechains (R1 and R2) as seen below:
1. What is the pI of pennywisine? What structure will pennywisine have its pI? (draw it)
2. What overall charge would have at pH 2 and pH 10? Explain.
3. Sketch the titration curve that would result if the completely unprotonated form of pennywisine was titrated with HCl.
a. Be sure to label the midpoints (and pH values at which they occur) and the endpoints (equivalence points).
b. Draw the correct structures (in terms of protonation that would be found and the 1st and 3rdendpoints (equivalence points).
4. How many mL of 10 M NaOH will have to be added to the fully protonated form of pennywisine to create 375 mL of a 150 mM pennywisine buffer at pH = 8.38?
5. Can pennywisine exist in water as it is shown to the structure to the left? Explain.
6. If pennywisine were dissolved in water at pH =7, what will the two strongest intermolecular forces of attraction between pennywisine and the water. Explain.
7. Based on any resemblance you note between the sides chains of normal amino acids and those of pennywisine, under what conditions will both pennywisine sidechains react with ICH2COOH? Illustrate the organic mechanism of the reaction that will occur using these structures.