Biochemistry Final Exam (Exam 4) 200+ questions with correct answers
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Course
Biochemistry
Institution
Biochemistry
Biochemistry Final Exam (Exam 4) 200+ questions with correct answers/Biochemistry Final Exam (Exam 4) 200+ questions with correct answers/Biochemistry Final Exam (Exam 4) 200+ questions with correct answers
Biochemistry Final Exam (Exam 4)
One physical characteristic unites all the lipids of the body: what is it?
List examples the lipids of the body (9) - correct answer They're all insoluble in
water
- Fatty acids
- Triacylglycerols
- Glycerophospholipids
- Sphingolipids
- Eicosanoids
- Cholesterol
- Bile salts
- Steroid hormones
- Fat-soluble vitamins
What is the most major fat in the human diet?
What's another name for this fat?
Why is this our largest source of fat?
What is their structure? - correct answer - Triacylglycerols AKA triglycerides
- These are the largest form of lipid storage in plants & animals
- Glycerol backbone with 3 fatty acids (tri-) esterified to it
Where does digestion of long-chain lipids (triglycerides, triacylglycerols) begin
after ingestion?
By extension, this means very little digestion of these fats occurs where? (2) -
correct answer - Begins in the intestine
- No/little metabolism of triglycerides occurs in the mouth or stomach
What enzyme is produced by the cells on the back of your tongue?
,Biochemistry Final Exam (Exam 4)
What enzyme is produced by the cells in your stomach? - correct answer - Back
of tongue: lingual lipase
- Stomach: gastric lipase
When triglycerides enter the intestine, what gets released?
What does it cause? (2)
Those two things cause what products to be made? (2)
What does this allow for? - correct answer - Triglycerides enter small intestine:
cholecystokinin is released
- Cholecystokinin 1) signals gallbladder to release bile acids and 2) signals
pancreas to release pancreatic lipase and colipase
- The bile acid, pancreatic lipase, and colipase allow the triglycerides to be
digested
What are the degradation products of triglycerides? (2)
Where does this breakdown occur? - correct answer - Free fatty acids
- 2-monoacylglycerol (2-MG)
- Metabolism occurs in small intestine
What is the chemical process and the enzyme responsible for the metabolism of
phospholipids?
Where does this enzyme come from?
Where does this metabolism occur? - correct answer - Phospholipids are
hydrolyzed by phospholipase A2
- Phospholipase A2 is made by the pancreas
- Metabolism occurs in intestine
What is the chemical process and the enzyme responsible for the metabolism of
cholesterol?
Where does this enzyme come from?
,Biochemistry Final Exam (Exam 4)
Where does this metabolism occur? - correct answer - Cholesterol is hydrolyzed
by cholesterol esterase
- Cholesterol esterase is made by the pancreas
- Metabolism occurs in intestine
Free fatty acids, monoacylglycerol, cholesterol, and lysophospholipids (hydrolyzed
phospholipids) are packaged into ____________: these combine with
_______________ in the intestinal lumen to allow for what?
What does this NOT allow for?
What happens to this molecule instead? - correct answer Free fatty acids,
monoacylglycerol, cholesterol, and lysophospholipids (hydrolyzed phospholipids)
are packaged into micelles, which combine with bile acids in the intestinal lumen
- This allow for diffusion of lipid-soluble nutrients across the intestine and into
cells
- This does NOT allow the bile acids to enter the cells: they stay in the intestinal
lumen & get reabsorbed
- Once reabsorbed, bile acids are sent to the liver to be used again with fat
digestion
What type of intestinal cells can re-synthesize triglycerides?
What can they re-synthesize triglycerides from? (2) - correct answer - Intestinal
epithelial cells
- Use free fatty acids and 2-monoacylglycerol
Triglycerides are insoluble in water: how does the body package them to ensure
they can be transported?
What's contained within this package besides the triglycerides (3), and what's the
other name for this package?
What would happen if they weren't packaged in this way? - correct answer -
Packed within lipoprotein particles
- Contains: triglycerides, protein, cholesterol, phospholipids
, Biochemistry Final Exam (Exam 4)
- AKA Chylomicrons
- If triglycerides entered the blood directly, they'd coalesce into a big ball of fat
and impede blood flow
What are chylomicrons made of? (4)
Which is the most major component? - correct answer -
Triglycerides/triacylglycerol (MOST MAJOR)
- Protein
- Cholesterol
- Phospholipids
True or false: chylomicrons are mostly composed of fat and therefore must be
packaged to prevent coalescence in the blood into larger fat globules - correct
answer False: chylomicrons are made mostly of triacylglycerol, but they ARE the
packaged form that resists this coalescence, they don't need any further
processing to be safe
Once formed, where do chylomicrons get secreted?
Where do they ultimately arrive after this?
What does the body use chylomicrons for when they arrive in this ultimate
destination? - correct answer - Into lymph
- Into circulation
- Distribute dietary lipids to the tissues that need them
List the steps that chylomicrons take from the time they're released until they
become chylomicron remnants (8)
Place these in order on the exam - correct answer 1) New "nascent"
chylomicrons bond with HDLs
2) Chylomicrons bond with 2 apolipoproteins from HDLs (apoCII & apoE)
3) Chylomicron is now "mature"
4) Mature chylomicron activates LPL enzymes
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