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Flashcards in Lipids Deck (45):

what is the diff bw fats, oils and crude fat

fats: solid at room temp
oils: liquid at room temp
crude fat: ether exract of a food


What are the functions of facilitative Lipids

add palatability and texture
provide calories
stores as energy
promotes fat soluble vitamin absorption
many are saturated and monounsaturated


what is the function of functional lipids

cell regulation and metabolism
essential: linoleic acid and a-linoleic acid
conditionally essential: arachidonic acid (cats), docosahenoic acid(neonate), derived from EFAs
other functional fats


wht are the 4 structures

1. short chain fatty acids
2. MCT (medium chain triglycerides)8-12 carbon molecules
3. long chain fatty acids
4. PolyUnsaturated fatty acids


triacylglyerols are synthesized then...

stored as fat.


How are PUFAs named

By the double bonds (saturated, monounsaturated, polyunsat)
By position of first double bond (n-3, n-6, n-9)


polyunsaturated lipids are more susceptable to



How are lipids made in mammals

glucose and or amino acids are converted to acetyl coA then to saturated fatty acids (16 & 18 carbon)
desaturated to form monounsaturated fa of the n7 and n9 fa
enzymes are active when consuming low fat and high protein diets like herbavores
limited enzyme activity when consuming high fat diets like cats and dogs (directly use and store fa)


how are PUFAs made

elongation and desaturation of the n-6 pufa,linoleic acid and then-3 pufa, a-linolenic acid.
EPA and aracadonic acid are in the lipid bilayer of cell membrane and make inflammatory mediators


Linoleic Acid is needed in all animals and are found where?

in phospholipid ceramides
extruded fromepidermal keratinocytes as intercelluar lamellar granules. They enhance cell adhesion and make a water barrier to the epidermis.
with out this = dry flaky skin


what are the canine essential fatty acids

linoleic acid
a-linolenic acid (needed to make EPA)
mammals lack enzymes that insert double bonds before carbon 9
n-3 and n-6 PUFA can be elongated and desaturated


what are essential fatty acids for felines

Linoleic acid
arachidonic acid
Eicosaphentaenoi acid (EPA)
and possibly a-linolenic acid
cats reduced 6desaturase levels make the conversion of linoleic acid to arachidonic acid and a-linolenic acid to EPA difficult


What are sources of omega 6s or n-6 PUFAs

corn oil
cottonseed oil
peanut oil
safflower oil
sunflower oil
olive oil
soybean oil
canola oil


what are sources of omega 3s or n-3 PUFAs

fishoil (needed to make myelin)
flaxseed oil (linseed)-- linolenic acid
canola oil -- linolenic acid
soybean oil---linolenic acid


sources of energy and for the solubility of fat soluble vitamins

non-esterfied fa
triacylglyceride and triglycerides
cholesterol esters
fat soluble vitamins


What does the stomach do to digest fat



What does the duodenum do to digest fats

make lipid mycelles that are more water soluble with more surface area


What does the jejunem do for digestion of fat

enzymes attach to mycelles with coenzyme lipase


what digestion of fats is done in the ileum

lipids absorbed in the jejunem and duodenum. Enterohepatic circulation, bile acids are resorbed.


where does the lipase attach on the bile acids of the micelle

to the OH group


Where is the cleavage located for pancreatic lipase

1&3 carbon bonds of fatty acid


gastric liase, bile salts, pancreatic lipase, and colipase break down what

TAG into MAG and NEFA


What happens in the enterocytes

absorption and AG reformed. CM is formed. TAG(triacylglyceride) is put into chylomicron. Makes lipoproteins for the lymphatic system


Chylomicrons metabolized are

stored as fat in peripheral tissue andnot modify them.
broken down by lipoprotein lipase and stored in triacylglycerides or made into free fatty acids from the TAG within the adipocyte (via hormone sensative lipase) or from the chylomicron itself.


How are lipids used in the mitochondria

fatty acids to fatty acyl coA + carnatine= acyl carnatine
goes thru carnatine acyltransferases 1 and 2 in the mem.
+ coA regenerates carnatine to go back and acyl CoA
acyl Coa undergoes B-oxidation using e- and ox
phos. to make ATP or go into the TCA cycle


what are MCT's

8-12 carbon molecules rapidly hydrolyzed withinthe small int.
faster absorption than long chain fatty acids
portal circulation bound to albumin (bypass lymphatics but some go thru the hepatic duct)
uses hepatic unregulated b-oxidation and not
stored as fat.


How does Ruminant digestion of lipids work

Rumen microbes hydrolyze TAG and galactolipids release FFA
Glycerol and galactose fermented to SCFA
microbes hydrogenate fa to a more saturated state
the rumen reduces
microbes make new fatty acids
these fa arriving in the small int are diff than the dietary fa composition


what are the signs of fa deficiency

poor growth and weight gain
cutaneous changes (matted coat, scaly skin, tin discolored coat, weak cutaneous blood vessesl, increased transepidermal water loss)
Infertility and poor wound healing


How do lipids interact with other nutrients

high dietary lipid intake causes an increased antioxidant protection (vitamin E)
omega 3 PUFA are more suceptable to peroxidation than omega 6.


What is the difference between a normal diet and an omega 3 diet

normal: less EPA and more arachadonic acid
omega 3: more EPA and less arachadonic acid
There will bea shift in lipid membranes when on this diet but takes 8-12 weeks.


What are the eicosanoids and how are they made

1. prostaglandins (PG)
2. thromboxanes (TX)
3. leukotrienes (LT)
the are made by phopholipase A2, cyclo-oxygense or lipoxygenase reaking down PUFA


saturtated lipids have

no douoble bonds (palmitic acid)


Monounsaturated have

one double bond (count from the omega end)


Polyunsatuarated has

bond at the 6th carbon or lower (ex. linoleic acid)


alpha linoleic acid has double bonds at

n3, n6 n n9


arachidonic acid has bonds at

n6, n9, n12, n15


cats cannot synthesize what PUFA

arachadonic acid


what are the enzymes competed for bw n6 and n3 PUFA

6desaturase, zn, mg, biotin (cats dont hve enough of these)
elongase, pyridoxine, biotin
5desaturase, vitamin e
4desaturase, vitamin e


what is the end result of the n3 fatty acid

alpha linoleic acid to Docosahexaenoic acid (DHA) 22 carbons and has 6 double bonds


wat is the end result ofthe n6 fa

cis linoleic acid to a 22 carbon PUFA with 5 double bonds


vegetabe seed or oil sources can make

n3 or n6


omega 6 are from

terrestrial animal sources


omega 3 is from marine sources and makes

Platelets (thromboxane)
Endothelial Cells (prostacyclin)
Leukocytes (leukotriene)
less inflammation


omega 6 makes ...

Platlets (thromboxane A2)
endothelial cells (prostacyclin I2)
Leukocyte (leuotriene b4)
promote inflammation


Fat is needed for

skin and immune function