Download C483 Final Exam Study Guide The final will be held in Chemistry

C483 Final Exam Study Guide
The final will be held in Chemistry 122 at 8AM, Wednesday, December 14. There will be no
excused absences for the final.
There are two parts to the final exam.
A. 50 points covering chapters 18-19. This exam will look much like what you have
seen in the other midterm exams.
Major topics include: ammonia fixing pathway, glutamine synthetase, transamination
mechanism, essential/nonessential amino acids, carbon sources of nonessential amino acids, role
of THF, activated methyl cycle, ketogenic/glucogenic amino acids, entry of carbon backbone
into metabolism for the amino acids on the slides, branched amino acid problems like #40,
nitrogen cycle from muscle, urea cycle input and outcome and ATP expenditures, role of main
amino acids in nitrogen metabolism, compartmentalization of cells, specialization of organs in
metabolism, metabolism under well fed/fasting states, major points of pathway regulation, local
regulation, covalent modification, insulin/glucagon/epinephrine effects, hexokinase/glucokinase,
regulation of phosphorylase, diabetes
B. 100 point cumulative exam. This exam will cover major themes and integrated
concepts for the course. It will be about 1/3 multiple choice, 1/3 short answer, and 1/3 problems,
some of which are taken directly from the list below. These questions will also serve as a good
review for the major topics of the course. You are encouraged to use them as a study guide.
You may work with others in the class to work through these problems. The instructor and AI
will not assist you or provide answers.
Questions:
1. Pratt question 13.20, 14.14, 14.40, 14.59, 17.34, 18.41, 18.43, 19.28
2. Given a name, draw chemical structures of: ATP, all amino acids, all glycolysis intermediates,
acetyl CoA, all citric acid cycle intermediates
3. Explain the logic of these pathway regulations:
A. Phosphofructokinase, not hexokinase, is the main regulation site of glycolysis.
B. SuccinylCoA inhibits the entry of acetyl CoA into the citric acid cycle.
C. NADH inhibits pyruvate dehydrogenase.
D. Citrate inhibits the citric acid cycle and activates acetyl-CoA carboxylase.
E. Insulin leads to activation of glycogen synthase.
4. Describe each cycle/transport system (compounds, compartments, tissues) and explain its
purpose:
A. malate/aspartate shuttle
B. citrate transport system
C. Cori cycle
D. glucose/alanine cycle
5. For each of these cofactors, explain its chemical function and give an example of a particular
enzyme that would use it: TPP, PLP, biotin, FAD, NADPH. Be ready to draw mechanisms that
incorporate these cofactors. (Structures of cofactors will be given.)
6. Drawing figures. In the spaces below, draw an appropriately shaped figure, including
necessary axis labels.
A. A titration curve for lysine, with a side chain pKa of 10.5.
B. A DNA melting curve for a poly(AT) sequence and a poly(GC) sequence (indicate which is
poly(AT) and which is poly(GC))
C. A plot of initial velocity versus substrate concentration for a Michaelis-Menton enzyme.
D. The same plot as (B), but the enzyme is treated with a competitive inhibitor
E. a pH profile for an enzyme with two key ionized residues: a cysteine with pKa 4.2 and a
Histidine with pKa 8.2
F. Saturation curve for myoglobin and hemoglobin (indicate which is which)
7. Integrated metabolism
A. A molecule of glucose that you eat can eventually be transformed into part of a fatty acid that
you store. Circle the pathways/cycles below that are part of this overall flow of carbon atoms.
Cross out any that are not.
Gluconeogenesis, beta-oxidation, citric acid cycle, glycolysis, urea cycle, fatty acid synthesis
B. Trace the metabolic path of this glucose molecule through the enzymes it encounters along
the way to being made into fat. Write all the enzymes in the list below into the proper places in
the figure below. If the enzyme is not used, write its name in the “not used” box. If it is used,
write the enzyme in the order that the carbon atoms from glucose encounter the enzymes.
Pyruvate dehydrogenase, fumarase, aldolase, lactate dehydrogenase, pyruvate kinase, acetyl CoA
carboxylase, fatty acid synthase, hexokinase, carnitine acyltransferase, ATP synthase
B. What is the minimum number of glucose molecules that would be necessary to be the carbon
source for synthesis of a 16-carbon fatty acid through this pathway?
C. How many net glucose can be made from one molecule of a 16-carbon fatty acid?
8. Integrated metabolism
A. A molecule of glutamate that you eat can eventually be transformed into part of a glucose
molecule that you store in your liver. Circle the pathways/cycles below that are part of this
overall transformation. Cross out any that are not.
Gluconeogenesis, pentose phosphate pathway, glycogen synthesis, glycolysis, citric acid cycle
B. Trace the metabolic path of this glutamate molecule through the intermediates it becomes on
the way to being glucose. Draw the structure of glutamate and -D-glucose in the boxes.
Indicate the order of transformation by writing “1”, “2”, etc next to each appropriate structure.
Cross out the one molecule not involved in this pathway.
C. The nitrogen atom of glutamate must be removed by oxidative deamination, and is
incorporated into a molecule that is excreted. Draw the structure of this molecule.