Lesson 8 Biochemistry of lipid digestion and absorption. Mechanisms of
transport of simple and complex
lipids in blood and lymph. Lipoprotein structure, dynamic and metabolism.
Concepts and terms
a. Biochemical and nutritional differences between saturated and unsaturated fats
b. Emulsification, digestion and absorption of dietary lipids
c. Structural properties, origin, entero-hepatic circulation, and role of bile acids
d. Compare differences between absorption and transport of medium- and longchain fatty
acids
e. Illustrate mechanisms of inter-organ lipid transport in biological fluids
f. Lipoproteins: classification, composition, types, and roles
g. Metabolism of different lipoproteins and recognize the medical significance of
lipoprotein metabolism disorders.
Reading assignment
Garrett 757-761, Campbell 620-623.
Animation viewing:
http://www.wiley.com/college/pratt/0471393878/student/animations/lipoproteins/ind
ex.html
Homework exercises
1) TG consisting of 2oleic acids and one arachidonic acid was consumed and
digested and absorbed in intestine. Explain why after this process
arachidonic acid was found in TG contining stearic and palmitic acids.
2) Explain why total cholesterol blood volume is not not always can by used
as an indicator og hypercholesterolimeia. What is chloesterol profile?
Which of LP corresponds to «bad» and «good» cholesterol and why?
3) After dinner patient blood sample was collected. After collection blood
sample appears to have «milky» layer on surface. Explain this and name
main LP which presents in this layer.
4) Find information and explain role of CEPT and LCAT enzymes in reverse
cholesterol transport. Name two types of scavenger receptors in cholesterol
transport. What are their functions?
5) What is lipoprotein lipase? Explain it functions. To which condition will
lead decrease of level of lipoprotein lipase?
In-class exercises
Choose correct answer
1.In the intestine, the dietary fats are hydrolysed by
A.
triacylglycerol lipase
B.
C.
D.
adenylate cyclase
pancreatic lipase
protein kinase
2.HDLs are synthesized in
A.
C.
blood
muscle
B.
D.
liver
pancreas
3. Triacylglycerols are
A.
B.
C.
D.
soluble in water
insoluble in water
soluble in water at elevated temperature
partially soluble in water
4. Animals cannot convert fatty acids into glucose because
A.
acetyl CoA can not be converted to pyruvate
B.
absence of malate synthase
C.
absence of dehydrogenase
D.
absence of a-ketoglutarate dehydrogenase
5. What is the major protein constituent of high-density lipoprotein (HDL)?
A.
B.
C.
D.
Apolipoprotein A-l
Apolipoprotein C-l
Apolipoprotein E
None of these
6. VLDLs are synthesized in
A.
C.
blood
intestine
B.
D.
liver
pancreas
7. Chylomicrons are synthesized in
A.
C.
blood B.
intestine
liver
D.
pancreas
8. Medium chained fatty (MCFA) :
A. Transported exactly to liver for further oxidation
B. Requires bile acids for solubilization
C. Serves as a precursor for glucose synthesis
D. Contains 16-24 carbon atoms.
9. Enzyme colipase is
A. Cofactor for hormone sensetive lipase
B. Produced in liver
C. Cofactor for pancreatic lipase
D. Possess esterase enzymatic activity
10. HDL transport
A. Cholesterol form liver to peripheral tissue
B. Lipids from intestine to liver
C. Cholesterol from peripheral tissues to liver
D. Lipids from liver to peripheral tissue
11. Highest size and lipids content are observed in
A. HDL
B. IDL
C. VLDL.
D. Chylomicrons
12. Which of the following is NOT a lipid
A. Cholesterol
B. Creatine
C. Sphygomyelin
D. Phosphatidylcholine
Supplementary data
Figure 1. Lipid classification
Figure 2. Scheme of lipid digestion.
Figure 3. Schematic representation of lipoproteins functions and interactions.