PEPKC is expressed almost exclusively in the ________.
Ruminant feed contains ________ and __________, which are digested by....
complex starch and cellulose; microorganisms in the rumen
Digestion of carbohydrates in the rumen results in ________.
volatile fatty acids
The major volatile fatty acids that result from ruminant digest are....; the major source of carbons for gluconeogenesis in the ruminant liver is ___________.
acetate, propionate, and β-hydroxybutyrate; propionate
The hexose-monophosphate shunt is only active when...
there is a lot of glucose around
The pentose phosphate pathway generates __________ for _______ synthesis.
ribose; nucleic acid
The pentose phosphate pathway synthesizes NADPH in the liver, adipose, and lactating mammaries for...; in the adrenals and testis for...
fatty acid and cholesterol synthesis; steroid hormone synthesis
3 physiological roles of fat.
major storage form of energy, regulatory molecules/bioactive lipids, structural roles
Bioactive lipids play a major role in __________, a process in which...
inflammation; the body's WBCs detect foreign invades to protect the body from infection
To generate bioactive fatty acids, an external signal bind to a ________.
After the signal bunds to the receptor in the generation of bioactive lipids, PLA2 is activated, and it...
cleaves fatty acids from the #2 position of membrane phospholipids
Enzyme that cuts fatty acids off a glycerol backbone.
During generation of bioactive lipids, the fatty acids cleaved off by PLA2 is metabolized by __________ to __________
During the generation of bioactive lipids, PGG2s are further metabolized to... (3), which are bioactive lipids that...
PGE2, TX2, and PGI2; recruit and activate WBCs to amplify the immune response
NSAIDs block _______ to reduce _______.
Generic term for any 20 carbon fatty acid.
The functions of bioactive eicosanoids are best understood in...
the immune response and inflammation
Fatty acid are _______, ________ molecules.
______ and _______ fatty acids are clinically significant.
ω3 and ω6
Two significant groups of dietary PUFAs (polyunsaturated fatty acids) in animal heath:
n-6 and n-3
_________ is an essential fatty acid in humans, rodents, canines, and cats.
Cats require an extra essential fatty acid, _______.
Linoleic acid is metabolized to _______, which is further metabolized to bioactive __________.
arachadonic acid; n-6 eicosanoids
Linolenic acid (semi-essential) is metabolized to _______.
Two sources of arachadonic acid:
conversion of linoleic acid (primary) and direct consumption in animal products
2 sources of eicosapentanoic acid:
conversion of linolenic acids from vegetable oils; direct consumption from fish products
The term "2 series" refers to the 2 double bonds that remain after the conversion of ___________ to the ____________.
arachadonic acid; bioactive eicosanoid
The term "3 series" refers to the 3 double bonds that remain after the conversion of ___________ to the ______________.
eicosapentanoic acid; bioactive eicosanoid
________ eicosanoids are biologically more active than ______ eicosanoids.
Because of their increased number of double bonds, fish oils are susceptible to ________; when kept intact, they are useful in treating ________.
oxidation; chronic allergies and dermatitis
Cats lack ________ and therefore, they cannot...
Δ6 desaturase; initiate the conversion of linoleic acid to arachadonic acid
3 functions of cholesterol.
membrane structural component, steroid hormone precursor, bile sale precursor
Most fat digestion is initiated in the ________ by the following two mechanisms...
duodenum; emulsification by bile salts and hydrolysis by pancreatic lipase
When fat digestion in the duodenum involves bile salts, the mechanism is...
emulsification by bile salts to form micelles
When fat digestion in the duodenum involves hydrolysis, the mechanism is...
hydrolysis of the FA by pancreatic lipase to release monoglycerides and free fatty acids
When fat digestion in the duodenum results in hydrolysis and formation of monoglycerides and free fatty acids, these components are...
absorbed in the jejunum and reassembled into chylomicrons to re-enter circulation
Cholesterol is the precursor of ________.
Bile acid synthesis occurs in the _______, and bile acids function in ____________.
liver; fat digestion
The primary bile acids are...
taurocholic acid and glycocholic acid
In most species there is a mix of taurochoic and glycocholic acid as the bile acids, but in cats...
all bile acids are taurocholic acid they are prone to taurine deficiency
Bile acids are _________ and __________ during digestion in a process called ____________.
reabsorbed and recycled; enterohepatic circulation
All cat foods are supplemented with ________.
After dietary lipids are absorbed in the jejunum, the absorbed long chain fatty acids and monoglycerides are reassembled into ________ in the _________.
triglycerides; jejunal mucosal cells
The triglycerides that are reassembled in the jejunal mucosal cells are packaged into _________ by the enzyme ________.
chylomicrons; microsomal triglyceride transfer protein (MTP)
The drug Slentrol inhibits _______, and therefore blocking...... in order to treat......
Microsomal triglyceride transfer protein (MTP); packaging and transport of TGs in the jejunum mucosal cells; obesity in dogs by accumulation of lipids decreasing appetite
Elevated serum lipids; relatively uncommon in animals, but usually secondary to diabetes or other endocrine problem.
Elevated serum chylomicrons; clinically significant problem in companion animals.
The protein part of a lipid-protein complex.
The major component of chylomicrons.
triglyceride and cholesterol
The four major proteins of chylomicrons.
Apo A, Apo B48, Apo CII, Apo E
The cholesterol exchange protein of chylomicrons.
The transport/lipid packaging protein of chylomicrons.
The lipoprotein lipase activator of chylomicrons.
The protein that binds to the liver receptor for chylomicrons.
___________ are rapidly cleared from the blood after a meal.
During chylomicron metabolism, the chylomicron is secreted into the _______________ and them dumped into ____________.
lymphatic system; systemic circulation
During chylomicron metabolism, circulating chylomicrons become associated with the _____________ in __________, ___________, and __________ because these contain ____________.
surface of endothelial cells; adipose, muscle, and heart tissue; lipoprotein lipase
During chylomicron digestion, lipoprotein lipase is activated by interaction with _____________, which results in __________ of _________ within the chylomicron and uptake of _______ into the tissues.
Apo CII; lipolysis; triglycerides; fatty acids
During chylomicron digestion, as the chylomicron loses ___________, it shrinks and becomes a ____________. It also loses ________ and __________, but it retains _________ and __________.
triglycerides; chylomicron remnant; Apo A and Apo CII; Apo E and Apo B48
During chylomicron digestion, the chylomicron remnant is taken up by the __________ by the chylomicron remnant receptor, which recognizes _________.
liver; Apo E
During chylomicron digestion, after the chylomicron remnant binds to the liver, it releases _________ and _________ into the liver cell.
fatty acid and cholesterol
The liver DOES NOT store ________ or ________; storage of these substances is a pathological disease known as ________.
fatty acids or cholesterol; hepatic lipidosis
Fatty acids that are deposited in the liver by chylomicron remnant are repackaged into _______ and sent ___________.
very low density lipoproteins (VLDL); back into peripheral circulation
The major component of VLDLs.
triglyceride, cholesterol, cholesterol esters
Most of the triglyceride in VLDLs is leftover from ___________.
dietary TG from chylomicrons
__________ are difficult to clear from circulation.
VLDL is synthesized in the __________; VLDL transport _________ to the ___________.
liver; TG; peripheral tissues
During VLDL metabolism, __________ interacts with and activates _______ at the endothelial border of peripheral tissues.
Apo CII; lipoprotein lipase
During VLDL metabolism, lipoprotein lipase hydrolyzes the _______ from the ________ in the VLDL, which are then incorporated into _____________ for storage.
fatty acids; TG; adipose tissue
During VLDL metabolism, as VLDL lose ________ and _________, the VLDL becomes and Intermediate density lipoprotein (IDL).
TG and Apo CII
The 2 fates of IDLs.
uptake into the liver via the LDL receptor (preferred); further breaker to form LDL
LDL is composed mainly of _______ and ________.
Apo B100 and cholesterol
LDL binds inefficiently to _________, and therefore, it is...
LDL receptor; difficult to clear from the blood
HDL transports cholesterol from the _________ to the _______.
peripheral tissues; liver
HDL is synthesized in the...
liver and small intestine
HDL picks up _______ from the ________; this occurs when _______ activates the enzyme lecithin:cholesterol acetyltransferase, facilitating the transfer of ________ in the peripheral tissues to ______________ in the HDL particle.
cholesterol; plasma membranes; Apo AI; cholesterol; cholesterol esters
The cholesterol-containing HDL binds to a _________ on the surface of the ________, and ___________ are delivered.
HDL receptor; liver cell; cholesterol esters
HDL cholesterol delivered to the liver is converted to __________ or _____________.
bile salts; repackaged into VLDL
What is the main reason dogs and cats are protected from atherosclerosis?
they maintain elevated HDL levels
Persistently elevated HDL provides an effective mechanism to...
continuously remove cholesterol from the peripheral tissues and reduce risk of atherosclerosis
HDLs function _________; chylomicrons, VLDL, and LDL function in the __________.
constitutively; fed state
Fatty acid synthesis occurs when...
energy intake exceeds energy expenditure (fed state)
Fatty acid synthesis is driven by _________.
insulin (which increases during fed state)
Fatty acid synthesis takes place in which tissues?
liver and adipose
The major substrate for fatty acid synthesis in monogastrics.....; In ruminants...
excess glucose; acetate
What is the rate limiting step in fatty acid synthesis?
acetyl-CoA carboxylase (ACC)
Acetyl-CoA carboxylase (ACC) is regulated by...
insulin and glucagon
__________ turns on Acetyl-CoA carboxylase (ACC) by activating a protein that dephosphorylates and activates ACC in the fed state.
___________ activates AMP-dependent kinase, which phosphorylates and inactivates (inhibits) in the fasted state.
Acetyl-CoA carboxylase (ACC) converts _________ to ________, which contributes 2 carbon units to the ____________, a rxn catalyzed by __________.