Chem 410 Spring 2013 Biochemistry Exam IV
Name __________________________
Short answers (two to three sentences NOT BULLET POINTS each) 2 points
1) What is the difference between the composition of animal and plant fats?
2) The major loss (excretion) of cholesterol in humans takes place through what process?
3) Which apoprotein is responsible for receptor mediated uptake by the liver? Describe the life cycle of the
apoprotien.
4) What is the role of a chylomicron in lipid metabolism/transport and what are the key biochemical features
of the lipoprotein?
5) Citrate is a inhibitor of Glucose metabolism and is a result of __________ ?
6)
The b oxidation of one mole of palmitoleic acid (C-16:1) yields how many moles of AcetylCoA, FADH2 and NADH? Describe your calculation/metabolism
7) ________ catalyzes the first committed step of fatty acid biosynthesis and is on of its rate-controling steps
8) Condensation of malonyl-ACP and Acetyl ACP results in the liberation of what?
9)
The hormone ______ induces lipolysis, whereas the hormone ______ inhibits the process.
10) Describe the organs or tissues prefer to use ketone bodies such as acetoacetate as a fuel energy
source instead of glucose?
11) Lack of what metabolite results in the generation of ketone bodies by hepatocytes?
12) How are fatty acids larger than 16 carbons formed?
13) Water insoluble steroid hormones primarily exert their effect by ______________
14) ______ synthesize the catechols epinephrine and norepinephrine, which bind to the _____ receptors
15) A consensus sequence is _______________
16) The cAMP binding site for PKA is found on ___________________.
17) A PH or plekstrin homology domain is a region of a protein that
18) Gq linked receptors lead to what intracellular signaling molecule changes?
19) Which G protein subunit contains a WD40 repeat?
20) Which of the small G protein families is activated by SOS?
Part II. Answer EACH of the following questions.
1) What is the role of each of the major lipoproteins.
What are the major components of each lipoprotein? (5 points)
2) Familial hypercholesterolemia is a disease that leads to high concentrations of serum cholesterol.
Describe what is the malfunction of this disease and relate that to those with a high consumption of
cholesterol and those with a normal diet. (8 points)
3) G-Protein Signaling:
a. Describe a GPCR and how receptors bind their agonists. (4 points)
b. Explain the activation and inactivation of a heterotrimeric G protein. Include the receptors, all three
subunits of a G protein and the reaction. Not just the what, but the how. (6 points)
c. Describe the structural features of a GTP vs GDP bound alpha subunit. (5 points)
4) Have they found a cure for cancer? That is a question that a scientist is bound to hear several times from
friends and family. How would you explain that a single cure for cancer is not likely? Also explain how you
would explain to a friend or family member if a specific act or chemical would "cause cancer". (8 points)
Part III Answer 5 of the following questions (5 points each)
1) Describe the activation and inhibition of cAMP-Dependent Protein Kinase OR Protien Kinase C.
2) Pick one of the phospholipases involved in signal transduction and indicate it’s main substrate, the
product, what the product does in terms of signaling, any isoforms of the lipase, and its regulation.
3) Outline how beta oxidation degrades fatty acids to acetyl-CoA
4) Describe how the structure of Src reveals its autoinhibitory mechanism.
5) Explain and diagram the synthesis of fatty acids starting from acetyl-CoA in the mitochondrion to the
condensation of acetyl-ACP and Malonyl-ACP
6) Chemically describe the formation of DNA adducts by chemical carcinogens and the molecular biology
impact of these covalent changes to the DNA.
7) Why is it that some people can smoke or be exposed to carcinogens without affect while other people
that smoke are afflicted with cancer? What enzyme(s) is(are) responsible for this variation? Are there
other factors that are involved? Be specific in biochemistry terms involving mechanism beyond the class
notes.
Part IV Answer ONE of the following TWO questions (20 points)
1) Draw the signaling pathway for the EGF receptor. Indicate each of the signaling components, the name
for each component, the biochemical features of each component and any important points or regulation
of each step. A simple diagram with one or two simple bulleted points will not be enough.
Pick one of the following diseases that involve growth factor pathway signaling and describe the nature of
how improper signaling leads to the disorder (Insulin and diabetes, transforming growth factor beta and
motor neuron disease, or EGFR (Erb2 or HER) and Cancer).
2) Draw the signaling pathway for GPCR receptors that signal through Gq. Indicate each of the signaling
components, the name for each component, the biochemical features of each component and any
important points or regulation of each step. A simple diagram with one or two simple bulleted points will not
be enough.
Pick one of the following diseases that involves GPCR pathway signaling and describe the nature of how
improper signaling leads to the disorder (angiotensin receptor (AT2) and X-linked mental retardation, G12/13
and cancer, or Reactive oxygen species and heart disease ).
3) Draw the signaling pathway for dopamine signaling pathway. Indicate each of the signaling components,
the name for each component, the biochemical features of each component and any important points or
regulation of each step. A simple diagram with one or two simple bulleted points will not be enough.
Pick one of the following diseases that involves GPCR pathway signaling and describe the nature of how
improper signaling leads to the disorder (Amyloid plaque and neurofibrillary tangle formation in Alzheimer’s
Disease, Parkinson’s or cocaine/methamphetamine addiction).