Lipids Flashcards
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
- short chain fatty acids
- MCT (medium chain triglycerides)8-12 carbon molecules
- long chain fatty acids
- 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
oxidation
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
phospholipids monoglycerides non-esterfied fa triacylglyceride and triglycerides cholesterol cholesterol esters fat soluble vitamins
What does the stomach do to digest fat
emulsification
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
- prostaglandins (PG)
- thromboxanes (TX)
- 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 elongase 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
