Chap 10 Quiz Flashcards
The two locations of triacylglycerol digestion
Mouth and Stomach
The lipase for mouth and stomach
Mouth - lingual lipase
Stomach - gastric lipase
Both lipases for triacylglycerol digestion are active at
low pH
Triacylglycerol Digestion does not require
other proteins cofactors for max. activity
Synthesis of Triacylglycerols occurs predominantly in
enterocytes
Lipoproteins defined
Spherical micelles of phospholipids and apolipoproteins surrounding a neutral lipid core
Examples of Lipoproteins
HDL
IDL
LDL
VLDL
Structure of a Lipoprotein
Triglyceride and cholesteryl ester core
Phospholipid and cholesterol coat
Three mechanisms in which lipids enter the cell
Diffusion
Transport
Receptor-mediated endocytosis
Receptor-mediated endocytosis defined
Process in which the cell internalizes particles and uses the cholesterol contents of low-density lipoproteins
What binds to the receptor in receptor-mediated endocytosis
Ligand (clathrin)
Triacylglycerol Synthesis occurs where
liver and adipose tissue
Triacylglycerol Synthesis in the liver
de novo synthesis from actyl-CoA
Triacylglycerol Synthesis in adipose tissue
Re-esterifies free fatty acids (storage)
Enzymes for triacylglycerol synthesis are found in
the endoplasmic reticulum
In digestion lipids are emulsified by
bile salts into smaller droplets
Pancreatic lipase hydrolyzes
ester bonds in triacylglycerols releasing fatty acids
Triacylglycerols are packaged into what form to travel the blood stream
chylomicrons
Lipoprotein are complex particles composed of
Lipids (cholesterol/triglycerides) & Proteins
Chylomicrons are the
largest and least dense lipoproteins and are primarily transporting dietary triglycerides from intestine to tissue
HDL are synthesized in the ____ and involved in _____
liver; reverse cholesterol transport for excretion
Diffusion is a _____ process for lipoproteins
passive; moves from areas of high concen. to lower
Transport involves specific
carrier proteins embedded in cell membranes
Receptor-Mediated Endocytosis specific process involving
the binding of extracellular ligands
Reverse Cholesterol transport defined
Removal of cholesterol from the circulation and peripheral tissue to the liver
Enzyme that catalyzes the dephosphorylation of phosphatidate to diacylglycerol
Lipin
Lipid Storage droplets defined
The organelle that stores neutral lipids in the cells
Lipolysis Defined
The regulated mobilization and breakdown of triacylglycerols
**Lipolysis defined (extra)
triggered by hormone signaling
Occurs at low background levels
Regulated by AMP kinase
Types of triacylglycerol storage
Acute and chronic
Acute storage
+ Mobilization occurs over minutes to hours
+cAMP is manipulated via hormones and cell signaling cascades
Chronic storage
+ Occurs over weeks or longer
+ Partially affected by both levels of gene expression and diet
