Ch 17 Lipids/Fatty Acids Flashcards
(49 cards)
What is the primary metabolic similarity between Ruby-throated Hummingbirds, elite marathon racers, and hibernating bears?
They all rely on β-oxidation of fatty acids for energy.
What happens to fat during winter for bears?
Fat is oxidized to produce heat via electron transport uncoupled from ATP synthesis.
What is the main storage form of fat?
Triacylglycerols.
What are the four major functions of lipids in humans?
- Structural components of biological membranes
- Energy reserves
- Vitamins
- Hormones
What are the different types of lipoproteins and their primary functions?
- Chylomicrons: transport dietary lipids
- VLDL: transport endogenous lipids
- IDL: transitional form between VLDL and LDL
- LDL: transport cholesterol to tissues
- HDL: transport cholesterol from tissues back to the liver
True or False: All individuals have plaques in their arteries from their teenage years.
True.
What is the role of lipases in lipid metabolism?
They catalyze the release of fatty acids from triacylglycerols.
What initiates the catabolism of fatty acids?
Fatty acids are oxidized via β-oxidation to produce acetyl-CoA.
Where does β-oxidation of fatty acids occur?
In the mitochondria.
What is produced in each cycle of β-oxidation?
- 1 Acetyl-CoA
- 1 NADH
- 1 FADH2
How many ATPs does the oxidation of stearic acid (18 carbon) yield?
120 ATPs.
What is one reason unsaturated fatty acids yield less free energy than saturated fatty acids?
Unsaturated fatty acids contain double bonds that reduce the amount of energy produced during oxidation.
What happens to acetyl-CoA if carbohydrates are not consumed?
Acetyl-CoA accumulates as it cannot enter the citric acid cycle without oxaloacetate.
What are ketone bodies and where are they produced?
Acetoacetate, acetone, and β-hydroxybutyrate; produced in the liver.
What is the condition called when there is excessive production of ketone bodies?
Ketosis.
What is ketoacidosis?
A condition caused by excess acetoacetate and β-hydroxybutyrate lowering blood pH.
Fill in the blank: Fatty acids are liberated from glycerol to be oxidized to provide _______.
energy.
What is the process by which fatty acids cross the inner mitochondrial membrane?
Carnitine shuttle system.
What is the end product of β-oxidation of a 16-carbon fatty acid like palmitate?
Eight molecules of acetyl-CoA.
What is the role of cyclic AMP in lipid metabolism?
It initiates a kinase cascade that activates lipases.
What is the relationship between lipid metabolism and energy yield from fats compared to carbohydrates?
Oxidation of fats yields more energy due to a greater number of C-H bonds.
What is the effect of prolonged fasting on oxaloacetate levels?
Oxaloacetate is consumed to produce glucose, leading to acetyl-CoA accumulation.
What is the primary function of HDL?
Transport cholesterol from tissues back to the liver.
What is the significance of β-oxidation for energy production?
It generates acetyl-CoA, NADH, and FADH2, which are key for ATP production.
