Lipids Flashcards
What are lipids?
1) essential in diet
2) energy yielding macronutrient (9kcal per gram) <30% energy consumed
3) Organic
3) most do not dissolve in water
Lipids in the diet and in the body include:
1) triglycerides/fatty acids -human body stores fat this way
2) phospholipids (how fats interact with water)
3) sterols
Functions of Lipids in the body
1) energy
- major source of energy (like carbohydrates)
- stored in adipose tissue
2) protection
- temperature, shock
3) Structural -components of cell membrane
4) Regulation -BP and blood clotting *no limit to how many fat you can store
Fatty Acids definition
organic molecules with chains of carbon atoms with attached hydrogen with atoms and a acid group at one end
what is this a picture of
fatty acids
Classifications of Fatty Acids
definitons
1) saturated
- fully occupied with hydrogen atoms
2) monounsaturated
- one carbon double bond a pair of hydrogens missing
3) polyunsaturated
has two or more carbon double bonds
omega 3 and omega 6
Why do we hydrogenerate oils?
*define hydrogenation as well
remember: saturation adds shelf life
Hydrogenation: Chemically adding H for double bonds to add shelf life
Hydrogeneration makes oils less prone to spoilage and makes them remain solid at higher temperatures
which is worse: saturated fatty acids or trans fatty acids
trans fatty accid have been linked to similar problems as saturated fats with lesser amount in the diet
What are essential fatty acids? why is it essential
Omega 6 fatty acids (plants, animals)
omega 3 fatty acids (fish)
(body cannot produce but needs)
these two types of fatty acids are specific precursors to important regualtory moelcules and therefore consisered essential in the diet
Triglycerides
(where, function, %, definition)
the foods we eat contain triglycrides
function: to provide energy; 95%
contains three fatty acids (doesnt have to be all the same) +glycerol molecule
What are phospholipids?
phospholipids are like triglyceridesin which one fatty acid is replaced with a phosphate group
this phosphate group is soluble in water (head); hydrophilic
tails are hydrophobic; not soluble in water
Primary functions of phospholipds
1) phospholipid bilayer composes cell membrane
2) aids in lipid transport (lipoprotein*)
What are sterols?
(eg)
family of molecules consisting of interconnecting carbon rings
the most common sterol in the human body is cholesterol
Dietary cholesterol vs blood cholesterol
Cholesteorl in food is referred to dietary choelsterol and is found only in animal products; the human body makes more cholesterol than it needs–so it is not necessary to get choelsterol from food; used to make certain hormones, bile, vitamin D and cell membranes
Blood cholesterol; cholesterol transported in the blood by particles called lipoproteins; mechanism to transfer fats
LDL and HDL
*liver produces both molecule of cholesterol as well as lipoproteins
What does the body use cholesterol for, where to find cholesterol
-use to make certain hormones (testosterone and estrogen), bile, vitamin D (cholesterol —> UV light —-> Vitamin D) and cell membranes
*body routinely manufactures choelsterol for its own use
in foods…
plants and animals have sterols
ONLY ANIMAL TISSUE HAVE CHOELSTEROL
(highest in organ meats, egg yolk)
Only ____ produce cholesterol
animals
Digestion Fat and Lipids
(mouth, stomach, small intestine, colon)
mouth: some fats melt
stomach: fats floar but some mix with water and acid
small intestine: gallbladder secretes bile and fats are emulsified
Pancreatic lipases turn fats –> monoglycerides and fatty acids
absorption takes place
Once absorbed fat, will be transported primarily by lipoproteins
colon: some fat and cholesterol bound to fiber exit in feces
Emulsification definition and why is important
substance that suspends fat in liquids; with bile, it breaks down large droplet of fat into much smaller droplets
this makes it easier for fat-digesting enzymes (aka pancreatic lipase) to break down lipids
Lipids in Digestive Tract process w/ bile
- bile emulsifies lipids: breaks down larger droplet of fat into much smaller droplets
- fat-digesting enzymes are also released (pancreatic lipase)
- once broken down they form micelles (cluster of fatty acids)
- these fatty acids are absorbed across the lining of the small intestine; then are packaged into Lipoproteins (made of phospholipids) for transport
Micelles definition
small droplets of primarily fatty acids and other fat soluble substances
Digestion of fat begins with _______
emulsification
Lipoproteins definition
list types
lipoproteins: spherical bodies witha phospholid or protein shell that contains differnt types of lipids
1) Chylomicrons
2) VLDL(very low density lipoprotein)
3) LDL (low density lipoprotein)
4) HDL (high density lipoprotein)
Lipoproteins from the liver
VLDL, LDL, HDL
Chylomicrons
large lipoproteins that carry lipids from the small intestine, first via the lymph system and eventually into the blood stream
82% Triglyceride
8% Phospholipids
8% Cholesterol
2% protein
