Fat Metabolism Questions

1
Fat Metabolism Questions

• BC 368, Spring 2009

2
While working at the local blood bank to raise
funds for medical school, you draw a sample of a
potential donors blood which yields a murky pink
appearance. Concerned for the donors health and
suspecting hypertriglyceridemia, you send the
donors blood to the lab for additional analysis.
An extremely elevated triglyceride level of 1250
mg/dL (normal 150 mg/dL) confirms your
diagnosis. Which of the following mutations is
most likely the cause of your patients abnormal
blood sample?

• Carnitine acyltransferase I
• Acyl-CoA synthetase
• Trifunctional protein
• Lipoprotein lipase
• The murky appearance of the patients blood is
  not likely caused by a metabolic enzyme mutation
  the patient just needs to seriously alter his
  dietary habits.

3
Vitamin C is essential for the synthesis of
carnitine within the body. If John takes vastly
more vitamin C than the daily necessary value,
thus increasing his amount of carnitine, what may
we expect to occur within his body?

• Increased metabolism of all fuels
• Increased body weight
• Increased metabolic H2O production
• Increased triglycerides in the blood stream
• Increased anaerobic respiration

4
Which of the following is NOT a difference
between fatty acid and glucose breakdown?

• Electrons from beta-oxidation enter the ETC at Q,
  whereas electrons from glycolysis enter at
  complex I.
• Most common fatty acids cannot be used to produce
  glycogen, while glucose can.
• The brain normally uses carbohydrates, but not
  fatty acids, as a source of energy.
• Glucose can be broken down under aerobic and
  anaerobic conditions, but fatty acids can only be
  broken down aerobically.
• A deficiency in vitamin B2 (riboflavin) would
  disrupt glucose metabolism but not fatty acid
  metabolism.

5
A 29-year-old patient who has just had his
gallbladder removed is now complaining of
diarrhea. He has not changed his diet since the
surgery. The gallbladder is considered to be a
non-essential organ, so what is the most likely
cause of the diarrhea?

• The diarrhea is caused by bile salt deficiency,
  which results in fat particles not becoming
  emulsified.
• The diarrhea is caused by intestinal lipase
  deficiency, which results in triacylglycerols not
  being degraded.
• The diarrhea is caused by apolipoprotein
  deficiency, which results in fatty acids not
  circulating in the plasma.
• The diarrhea is caused by consumption of too many
  fat-free potato chips, which results in
  disgusting side effects.
• All of the above

6
Deep hibernating animals, such as a Jerboa, are
often found stocking up on food supplies
throughout the summer and fall to last them all
winter. During hibernation, their metabolic
rates significantly decrease. If you were to
take a blood sample of a hibernating animal in
the middle of winter, what would you expect to
find in terms of glucose levels, lactate, and
D-ß-hydroxybutyrate compared to a non-hibernating
control?

• Increased, increased, increased
• Decreased, increased, increased
• Decreased, decreased, increased
• Increased, decreased, decreased
• Decreased, increased, decreased

7
The cofactor biotin is needed for the activity of
acetyl-CoA carboxylase, among other reactions.
Which of the following effects could not be a
result of a serious biotin deficiency from eating
too many raw egg whites in an otherwise well-fed
individual?

• Increase in ketone bodies
• Increase in glucose from gluconeogenesis
• Decrease in citric acid cycle intermediates
• Decrease in fatty acid synthesis
• Raw egg whites would not cause a biotin
  deficiency

8
The Waterville P.D. pulls Mr. Teppler over for
erratic driving. The officer proceeds to
administer a breathalyzer test based on something
IN ADDITION to the erratic driving. Mr. Teppler
has not been drinking so what could be going on?

• Mr. Teppler has pernicious anemia.
• Mr. Teppler is suffering from uncontrolled
  diabetes mellitus.
• Mr. Teppler is suffering from hyperammonemia.
• Mr. Teppler has ornithine transcarbamoylase
  deficiency.
• Mr. Teppler is high as a kite on illegal drugs.

Mr. Teppler
9
Which statement is true?

• Fatty acid synthase is one polypeptide in all
  organisms.
• The acyl carrier protein of fatty acid synthase
  has biotin as part of its swinging arm.
• Fatty acid synthase has 8 active sites.
• All of the catalytic steps of fatty acid synthase
  are the same in all organisms.
• The fatty acid synthase reaction yields NADPH.

10
Dave stopped swimming in college and has since
put on a few pounds from too many years of eating
Cheetos and watching House. Since the memories
of 5 AM swim practices still haunt him, he wants
to lose weight the easy way. His doctor
prescribes him a new class of drug that will help
him lose weight by disrupting fatty acid
synthesis. Which is the most likely candidate
for this new drug?

• An inhibitor of the citrate transporter
• A synthetic concentrate of fat-free Pringles
• An activator of insulin-dependent protein
  phosphatase
• Carnitine
• An allosteric activator of carnitine
  acyl-transferase I

11
Annoyed by the fact that humans cant have a net
production of glucose from fatty acids, a mad
scientist tries to bypass this problem by
creating an overactive citrate lyase enzyme. He
thinks that bypassing the steps of the TCA in
which CO2 is normally lost by using citrate lyase
to convert citrate directly to oxaloacetate, he
can create a net production of glucose from fatty
acids. Which effect will the scientist NOT see?

• Hepatomegaly due to fatty acid build-up.
• Lower overall energy charge.
• Low matrix acetyl-CoA concentrations.
• High cytosolic acetyl-CoA concentrations.
• Increased glycogen stores.