27 Questions
What is broken down into 2 fatty acids and a monoacylglyceride during digestion?
Triglycerides
Where do micelles carry fatty acids to?
Enterocyte
What is used to transport LDL into cells?
LDL receptor
Where do medium and short chain fatty acids get transported directly into?
Capillaries
What carries cholesterol back to the liver?
HDL
Where are long chain and very long chain fatty acids resynthesized as triglycerides?
Enterocyte
What lipoprotein contains the highest proportion of cholesterol?
LDL
Where are triglycerides transported into on chylomicrons?
Lymph
Where must excess protein and carbohydrate first go?
Liver
What is used to carry fatty acids to the enterocyte?
Micelles
Where do chylomicrons transport triglycerides to?
Lymph
What lipoprotein carries triglycerides, cholesterol, phospholipids, and proteins?
VLDL
Which enzyme breaks down VLDLs and chylomicrons, releasing fatty acids for storage as triglycerides in adipose cells?
Lipoprotein lipase
What is the first energy storage site used when energy is needed?
Glycogen stores
Which hormone activates Hormone Sensitive Lipase, breaking down triglyceride stores in adipose tissue?
Glucagon
What facilitates fatty acid uptake by cells and their entry into mitochondria for beta-oxidation?
Fatty acid transfer proteins (FATPS)
What combines with oxaloacetate to enter the citric acid cycle during fatty acid metabolism?
Acetyl-CoA
In what condition are ketone bodies formed during energy metabolism?
Severe energy deprivation
What is the primary function of ketone bodies during energy metabolism?
Provide energy to the brain and peripheral tissues
Where is excess energy from fat stored via chylomicrons?
Adipose tissue
What hormones regulate the breakdown of stored triglycerides in adipose tissue?
Epinephrine, norepinephrine, glucagon, and adrenocorticotropic hormone
What is the primary site for the breakdown of stored triglycerides when energy intake is insufficient?
Adipose tissue
What is the role of ketone bodies in preventing excessive muscle protein loss during energy deprivation?
Prevent excessive muscle protein loss for gluconeogenesis
What is the function of Carnitine translocase (CAT) in fatty acid metabolism?
Transport of fatty acids across the mitochondrial inner membrane
What is the primary function of Acyl-CoA synthetase in fatty acid metabolism?
Conversion of fatty acids to Fatty-Acyl-CoA in the cytoplasm
What is the role of inner mitochondrial membrane palmitoyl transferase 2 (CPT2) in fatty acid metabolism?
Conversion of FA-acyl-carnitine back to FA-acyl-CoA
What is the function of fatty acid transfer proteins (FATPS) in fatty acid metabolism?
Facilitate the uptake of fatty acids by cells
Study Notes
Lipid Metabolism and Energy Utilization
- Triglycerides are produced endogenously and transported in VLDLs to adipose tissue for storage.
- Lipoprotein lipase in blood vessel cells breaks down VLDLs and chylomicrons, releasing fatty acids for storage as triglycerides in adipose cells.
- Lipids from the diet can be immediately utilized for energy or stored in adipose tissue.
- When energy is needed, glycogen stores are used first, then the body turns to adipose tissue for fat stores.
- Glucagon activates Hormone Sensitive Lipase, breaking down triglyceride stores in adipose tissue to release fatty acids and glycerol.
- Fatty acids and glycerol from adipose tissue are transported to cells with mitochondria, where they can be used to produce ATP through beta-oxidation.
- Fatty acid transfer proteins (FATPS) facilitate fatty acid uptake by cells, and carnitine facilitates their entry into mitochondria for beta-oxidation.
- Acetyl-CoA from fatty acids combines with oxaloacetate to enter the citric acid cycle, but ketone bodies are formed in severe energy deprivation or low carbohydrate intake.
- Ketone bodies provide energy to the brain and peripheral tissues, conserve glucose, and prevent excessive muscle protein loss for gluconeogenesis.
- Excess energy from fat is stored in adipose tissue via chylomicrons, while excess protein and carbohydrates must first be converted to triglycerides in the liver.
- When energy intake is insufficient, stored triglycerides in adipose tissue are broken down by hormone-sensitive lipase, releasing fatty acids and glycerol into the bloodstream.
- Hormones such as epinephrine, norepinephrine, glucagon, and adrenocorticotropic hormone regulate the breakdown of stored triglycerides in adipose tissue.
Test your knowledge of lipid metabolism and energy utilization with this quiz. Explore topics such as triglyceride production, lipoprotein lipase, energy utilization from diet, adipose tissue storage, and the role of hormones in regulating triglyceride breakdown.
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