Download C383 Study Guide for the Final Exam Spring 2017 Basic Information

C383 Study Guide for the Final Exam
Spring 2017
Basic Information
 Final Exam: Wednesday, May 3, 5PM in Ballantine 013
 Arrive early for assigned seats
 Bring your student ID. If you do not, you will need to bring it Saturday!!!
 You may use a NON-PROGRAMMABLE calculator.
 All papers, books, phones, and electronic devices must be in a sealed bag and PLACED
AT THE FRONT OF THE ROOM.
Exam Content: The exam will have two major parts.
A. about 50 points covering chapters 27-31. Major topics include: hormone sensitive
lipase, steps of beta-oxidation, ketone bodies, contrast fatty acid degradation and synthesis,
regulation of acetyl CoA carboxylase, stages of cholesterol synthesis, regulation of cholesterol
synthesis, ammonia fixing pathway, glutamine synthetase, transamination reaction,
essential/nonessential amino acids, carbon sources of nonessential amino acids, role of THF,
ketogenic/glucogenic amino acids, entry of carbon backbone into metabolism for the amino acids
on the slides, motifs in catabolism of branched amino acids, nitrogen cycle from muscle, urea
cycle input and outcome and ATP expenditures, role of main amino acids in nitrogen metabolism
B. about 100 point cumulative exam. This exam will cover major themes and integrated
concepts for the course.
Exam format: It will be about 1/3 multiple choice, 1/3 short answer, and 1/3 problems. These
questions will serve as a good review for the major topics of the course. Approximately 1/3 of
the questions on the final will come directly from the questions below and the practice final
exam. 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. S-acetonyl-CoA (shown below) has by synthesized and tested as an inhibitor of citrate
synthase.
A. Write the reaction catalyzed by citrate synthase.
B. Why is the name of this enzyme not “citrate synthetase”?
C. The Lineweaver-Burk plot of this enzyme with and without the inhibitor is shown below.
What type of inhibitor is it? Explain.
D. Based on these data, how would you expect this inhibitor to effect pyruvate carboxylase?
How would this effect gluconeogenesis?
2. Recognize names and/or chemical structures of: ATP, all amino acids, all glycolysis
intermediates, acetyl CoA, all citric acid cycle intermediates. Know 1 and 3-letter abbreviations
of amino acids.
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. citrate transport system
B. Cori cycle
C. 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
6. Draw the structures of the following molecules in their major ionization state in a buffer at pH
3 and a buffer of pH 7. (See a table for necessary pKa values.)
A. cysteine
B. oxaloacetate
C. D-mannose
D. the tripeptide PKV
7. 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)
8. 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?
9. 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.