Lipids Flashcards
Most of the fat in our diet is
TAG- triacylglycerol or triglyceride
What is the physiological fuel value for fat?
9 kcal / g
TAG=?
Triacylglycerol or triglyceride
What are some functions of fat
Source of energy Carrier for fat soluble vitamins Source of essential fatty acids Insulation Lubricant Protect internal organs Precursors for hormones Structural functions
TAG= 95% of __________, 85% of ________in the body
Dietary fat
Stored energy
Examples of lubrication as a function of fat
Gland in eyelid secretes lipid compounds to protect surface of the eye
What are the fat soluble vitamins
A,D,E & K
What are the two essential fatty acids
Omega 3 (linolenic ) Omega 6 ( linoleic )
Fat is needed for
Absorption
What are some structural functions of fat in the body
Membranes ( barrier function)
Phospholipid bilayer
Cholesterol, sat. Fatty acid, trans-FA:stiffen
Trans-FA have what effect on membranes
Reduce fluidity
The amount of cholesterol affects what in membranes
Fluidity
Phospholipid bilayer consists of
Hydrophilic polar heads on the outside, and hydrophobic non polar tails on the inside
The “tail” in a phospholipid bilayer is
Fatty acid
The “ head” in a phospholipid bilayer is
Glycerol-P
Cholesterol is important in
Membrane structure
This type of fatty acid is bad in your diet
Trans-fatty acid
_________&_____prevent hydrophobic chains from packing too tightly
Cholesterol and CIS- fatty acids
In relation to the appearance of the fatty acid tail, saturated fatty acids are (bent/straight)
Straight
In relation to the appearance of the fatty acid tail, cis-unsaturated fatty acids are (bent/straight)
Bent
Where is cholesterol in the cell membrane
Between the tails in the lipid bilayer
In relation to the appearance of the fatty acid tail, trans fatty acids are (bent/straight)
Straight
Straight fatty acid tail ( decrease/ increase) fluidity if the membrane while bent fatty acid tails ( decrease / increase) fluidity if the membrane
Decrease
Increase
What are some functions of fat in food
Carrier of flavor components and fat soluble vitamins ( marbling in steaks)
Desirable qualities: smoothness: emulsifier
Concentrated source of energy
Satiety value
Another name for lecithin?
Phosphatidylcholine
Esters of fatty acids (FA) with various alcohols
Includes fats, oils, waxes
Simple lipids
Fats and oils are esters of fatty acids with _________
Glycerol
Waxes are esters of fatty acids with _____
Alcohol other than glycerol
Esters of fatty acids containing non lipid substances
Compound lipids
What are some non lipid substances in compound lipids
Phosphorus (phospholipids : lecithin)
CHO ( glycolipids) (tears)
Protein: ( lipoproteins)
This has an important role in the transport of fat through body
Protein ( lipoproteins)
________ make up ~95% of lipids in food and feed
Triglycerides (TG)
_____ and ____ quantitatively most important
Fats and oils
Livestock feeds seldom over ____ of calories from fat
5%
Use a bomb calorimeter to get total energy content _____
Gross energy
These three are important in metabolism
Glycolipids, lipoproteins, sterols
What is the value of gross energy value for fat
9.45 kcal/g
9.45 kcal/ g x________ = 9 kcal/g
Digestibility ~80-90%
Major storage form of energy in the body
Triglycerides/ triacylglycerols (TAG)
Triglycerides/ triacylglycerols (TAG) are compared of ______ backbones attached by an ester bond to _______ side chains
Glycerol
3-fatty acids
Triglycerides/ triacylglycerols (TAG) ate typically seen as two or more different fatty acid residues or ________ _________ (versus ________ _______)
Mixed triglyceride
Simple triglyceride
Pancreatic lipase an only attack _______ ester bonds and is the primary enzyme in _________ _______
Outside
Lipid digestion
Products of pancreatic lipase
2 fatty acids
Monoglyceride
Another name for lecithin
Phosphatidylcholine
Phospholipids are a major component of
Cell membranes
Phospholipids have a glycerol backbone with
2 fatty acids and a phosphate group (PO4)
______ _____ are the simplest if lipids
Fatty acids
Fatty acids consist of
Polar head group (carboxylic acid) Hydrophobic tail ( nonpolar) long hydrocarbon chain
C__-C__ are volatile
C2-C6
C2=
Acetic acid
C3=
Propionic acid
C4=
Butyric acid
C5=
Valeric acid
C16=
Palmitic acid
C18=
Stearic acid
C14=
Myristic acid (palm oil)
C__ -C___ are water soluble in decreasing amounts
C2-C6
These three chain lengths of fatty acids are in milk fat
C4,C6,C8
> C8 are _____ at room temperature
Solid
C___ and C____most common saturated fatty acids
C16 & C18
Double bonds (increase / decrease ) melting point
Decrease
Increasing chain length (increases / decreases) melting point
Increases
Fatty acid hydrocarbon chains are ___ to ___ carbons in length
4-24
In saturated fatty acid chains
-all C-C bonds are _______
Single
In unsaturated fatty acid chains
Contains one or more
C=C double bond
One C=C bond is called
Monounsaturated
2 or more C=C bonds are
Polyunsaturated
The CIS form of fatty acids causes the chain to
Bend because the H’s are in the same side of the double bond
The reactive end of the carbon chain is the
Carboxyl End (elongation happens here)
From a nutritional standpoint in the nomenclature of fatty acids you count from the _____ end
Methyl
This is a very large complex enzyme that builds fatty acids two carbons at a time.
Fatty acid synthase
w6;C18:2 =?
Linoleic acid
These are precursors for prostaglandins, essential in the diet
Omega 6 fatty acid
Linoleic
w3;C18:8 =?
Linolenic acid
This is essential in the diet for the formation of DHA and EPA
Omega 3 fatty acid
Linolenic
Linoleic –> ______________(C__:______). –> prostaglandins
Arachidonic (C20:4 w6)
Linolenic–> _______________( _ _ ;__:___) –>________________( _ _; __:___)
Eicosapentaenoic acid
(EPA; 20:5 w3)
Docosahexaenoic acid
(DHA; 22:6 w3)
You need only around ~1 ______ of oil per day
Tablespoon
Tropical oils are usually
Saturated
Canola oil used to be called
Rape seed oil
The oil with the least saturated fat and most omega 3 is
Canola oil
What oil has the most saturated fat
Coconut oil
What oil has the greatest amount of monounsaturated fat and considered healthier that the others
Olive oil
What is high in omega 3
Flax seed (linseed oil / meal)
What is high in omega six
Safflower
Sources of linoleic acid (omega 6’s)
Corn oil, safflower, soybean, cottonseed, sunflower seed, peanut oil
Sources of linolenic acid
Believed to enhance coats of animals
Linseed( flaxseed), canola, small amount in soybean oil
Sources of arachidonic acid
Meats ( animal fats)
Sources of EPA and DHA
Fish, (cold water fish-salmon) and marine algae
The ___ conformation of hydrogenated fat is found in nature
CIS
The ____ conformation of hydrogenated fat Is seen in synthetic fats such as margarines that have been partially hydrogenated
Trans
What are some potential problems with the trans configuration of hydrogenated fat
Causes unfavorable lipoprotein profile ( HDL decreases and LDL and total cholesterol increases )
Can interfere with essential fatty acid metabolism
New food labeling rules
The “good” cholesterol
HDL
The “bad” cholesterol
LDL
A low HDL level and high LDL level can lead to
Strokes and heart attacks
The major digesting enzyme of triglycerides
Pancreatic lipase
Two minor enzymes in triglyceride digestion
Gastric lipase from stomach
Intestinal lipase
In nursing ruminants______ _______ from base of tongue starts milk fat digestion in the _____
Pre gastric esterase
Abomasum
Fats enter small intestine from stomach as a _____ ______ (due to stomach movements)
Coarse emulsion
Lipase (can / cannot). Attach to a lipid droplet in the presence of bile salts
Cannot
_____ acts as an “anchor” for lipase
Colipase
Colipase is secreted from the _______ as______
Pancreas
Procolipase
Procolipase –?–> colipase
Trypsin
This is required for lipase activity when bile salt is present
Colipase
TAG (Triacylglycerol or triglyceride) is produced in the
Smooth endoplasmic recticulum (ER)
Protein (ApoB-___) produced in
ApoB-48
Rough ER
Assembly of lipoprotein ___________ in ER and Golgi apparatus
Chylomicron
______ is the only tissue that can use glycerol
Liver
VLDL=
Very low density lipoprotein
High % lipid
Low % protein
LDL=
Low density lipoprotein
HDL
High density lipoprotein
Protein that activates lipoprotein lipase
C2
Enzyme located on walls of capillaries of many tissues
Lipoprotein lipase
Lipoprotein lipase releases
Fatty acids and glycerol
____ can deliver cholesterol to cells and excess cholesterol can trigger the formation of
LDL
Plaque
______“picks up” cholesterol from body cells and can also remove cholesterol from plaque
HDL
LDL also accepts cholesterol from ___. ______removed LDL from blood and converts cholesterol into _____
HDL
Liver
Bile
________is manufactured by the liver and is also taken from foods
Cholesterol
Heart LPL has a ____Km
Low
Adipose has a ____Km
High
In ruminants, micro organisms break down FA to _______&_______
3 free FA
Glycerol
DHAP=
Dihydroxyacetonephosphate
Ruminant fat is (more/less) saturated than non-ruminants
More
Ruminant meat and dairy products = ____ of fat as trans FA
1-8%
Up to _______% of hydrogenated vegetable oils are trans FA
40-50%
_____% of trans FA in US diet from hydrogenated oils
75-90%
CLA=?
Conjugated linoleic acid
CLA is found in ________ products and other ________ foods
Dairy
Ruminant
CLA is formed by micro organisms in the _____
Rumen
CIS ___,trans-___._________________ acid most common CLA
CIS 9,trans-11 octadecadienoic acid
A conjugated double bond has ___ single bond(s) between double bonds
One
A non conjugated double bond has ___ single bond(s) between double bonds
Two
CLA has ________________effects, inhibits proliferation if some ________
Anti carcinogenic
Cancers
CLA has antiatgerogenic effects meaning
Lowers total and LDL cholesterol
This reduces fat and increases lean body mass in some species, enhanced some immune response, and increases rate of bone formation in growing animals
CLA
Conjugated linoleic acid
Chylomicrons are produced in _____________. And carry __________ from diet in lymph and blood.
Interstitial epithelial cells
Triacylglycerols
VLDL is produced in _______.
Carries synthesized TAG (mainly from ______) in _______.
Liver
Carbohydrates
Blood
IDL=?
Produced in _____, ( remnant of __________ after triacylglycerol digestion.
It is endocytosed by ______ or converted to ____.
Intermediate density lipoprotein
Blood
VLDL
Liver, LDL
LDL is produced in ________. (Remnant of ____ after triacylglycerol digestion; end product of ______)
Contains high concentration of _______ and _____________
Endocytosed by ______ and ___________ ________.
Blood.
IDL, VLDL
Cholesterol, cholesterol esters liver, peripheral tissues
HDL= “_____” cholesterol
Produced in _______& __________.
Exchanges _________ and ______ with other ________.
Functions in the return of ________ from peripheral tissues to ______
Good
Liver and intestine
Proteins and lipids, lipoproteins
Cholesterol, liver
The ____ ____ are the simplest of the lipids
Fatty acids
A fatty acid containing one carbon -carbon double bond
Monounsaturated
A fatty acid containing two or more carbon-carbon double bonds
Polyunsaturated
Most fatty acids have and ______ number of carbon atoms
Even
The two essential fatty acids
Linoleic acid (18:2 w-6) Linolenic acid (18:3 w-3)
Humans are incapable of forming double bonds beyond the ____ carbon in the chain, which is why there are essential fatty acids
Ninth
TAG that contain a high proportion of relatively short chain fatty acids or unsaturated fatty acids tend to be _______ at room temperature
Liquid (oils)
TAGs made up of saturated fatty acids of longer chain length have a higher melting point and exists as _______ at room temperatures
Solids
_____ are monohydroxy alcohols of steroidal structure, with cholesterol being the most common example.
Sterols
Cholesterol is only present in _______ _______.
Animal tissues
Cholesterol is the precursor for many important steroids in the body
Ex:
Bile acids
Steroid sex hormones ( estrogens, androgens, progesterone)
Adrenocortical hormones
Vitamin D of animal tissues ( cholecalciferol)
The lipids belonging to phospholipids contain _________
Phosphate
A constituent of cell and organelle membranes, __________ serve as a conduit for the passage of water soluble and fat soluble materials across the membrane.
Phospholipids
The dietary lipid targeted for digestion is __________ by a very efficient process, mediated mainly by _____ ____.
Emulsified
Bile salts
The emulsification of lipids increases the ____ ____ of the dietary lipid targeted for digestion.
Surface area
Most dietary TAG digestion happens in the ______ of the ______ ________.
Lumen
Small
Intestine
Dietary lipids include 1. 2. 3. 4. These lipids enter the stomach largely intact
- Triacylglycerol (TAG)
- Cholesterol
- Cholesterol esters
- Phospholipids
Only ______ are acted upon in the stomach. _______ hydrolyzes medium and short chain FA
TAGs
Gastric lipase
Short chain free fatty acids in the lumen of the SI move directly into the ______ and combine with ______ and are then transported to the ________.
Blood
Albumin
Liver
The lipoprotein B-48 is synthesized in the _____ and _____ _______.
ER
Golgi apparatus
The protein portion of any lipoprotein is called the
Apolipoprotein
___________ are the primary form of lipoprotein formed from exogenous (dietary) lipids
Chylomicrons
The role of the chylomicron is to deliver dietary ______ mostly to tissues other than the _____, such as _______ and _______ tissue.
Lipid
Liver
Muscle
Adipose
Much of the lipid delivered to the liver is in the form of ________ ________.
Chylomicron remnants
______ are the most abundant lipid in the diet, and are also the most abundant lipid in chylomicrons.
TAG
As lipids are removed from chylomicrons, they undergo intravascular conversion to ________ _______.
Chylomicron remnants.
Chylomicrons are transported by the blood throughout all tissues in the body, whole undergoing intravascular hydrolysis at certain tissue sites. This hydrolysis occurs through the action of the enzyme
Lipoprotein lipase
This enzyme is associated with the endothelial cell surface of the small blood vessels and capillaries within non hepatic tissue such as ______ and _______.
Lipoprotein lipase
Adipose
Muscle
The blood vessels of the ______ do not have LPL
Liver
The lipid is synthesized in the ____________, transferred to the ___________ and excreted from the cell along with apolipoprotiens B-100.
Smooth ER
Golgi apparatus
The ______ is the key player in lipid transport, because it is the site of synthesis of lipoproteins formed from endogenous lipids and apoproteins.
Liver
The liver is capable of synthesizing new lipids from non lipid precursors such as _______ and ___ ______.
Glucose
Amino acids
The liver can also take up and catabolism exogenous lipids delivered to it in the form of _________ _________, repackaging their lipids into _____ and ______ forms
Chylomicron remnants
HDL
VLDL
Adipose is involved in absorbing ______ and _______ from chylomicrons through the action of _________.
TAG and cholesterol
Lipoprotein lipase
These are the major storage site for TAG
Adipocytes
______ accelerates the entry of glucose into the adipose cells
Insulin
______ are the major lipids in the diet
Triacylglycerides (TAG)
TAGs are digested to _________ and _________, which are resynthesized into TAG in _______ _______ _______, packaged in ____________ and secreted by way of the _____ into the blood.
Fatty acids and 2-monoacylglycerols.
Intestinal epithelial cells
Chylomicrons
Lymph
The _____ ______ of the chylomicron TAGs are stored mainly as TAG in _________ cells.
Fatty acids
Adipose
The _________ of the diet are emulsified in the intestine by _____ ______, which are synthesized in the _____ and stored in the ________.
Triacylglycerols
Bile salts
Liver
Gallbladder
The enzyme _______ ________ converts the triacylglycerols in the lumen of the intestine to ______ ______ and ____________, which interact with bile salts to form tiny micro droplets called _________
Pancreatic lipase
Fatty acids
2-monoacylglycerols
Micelles
The FA and 2-monoacylglycerols are absorbed from these micelles into the ______ _______ ______, where they are resynthesized into _________.
Intestinal epithelial cells
Triacylglycerols
Triacylglycerols ate packaged with _____,________,_____ and other compounds into the lipoprotein complexes known as ___________, which are secreted into the _______ and ultimately enter the _________.
Proteins, phospholipids, cholesterol
Chylomicrons
Lymph
Fats must be transported in the _____ bound to _____ or in _______ complexes because they are insoluble in water.
Blood
Protein
Lipoprotein
The TAGs of VLDL are synthesized in the _______.
Liver
When lipoproteins pass through blood vessels in ________ tissue, third TAGs are degraded to _______ ______ and ________.
Adipose
Fatty acids
Glycerol
The remnants of the chylomicrons are cleared from the blood by the _____.
Liver
The remnants of the VLDL can be cleared by the ______, or they can form a _____, which is cleared by the _______
Liver
LDL
Liver
Two types of lipoproteins are produced in the fed state
Chylomicrons, VLDL
_______FA have single bonds between the carbons in the chain, and _________FA contain one or more double bonds.
Saturated
Unsaturated.
The most common saturated FA present in the cell are____________(C__) and ___________(C__).
Palmitic acid C16
Stearic acid C18
Cholesterol adds __________ to the phospholipid bilayer of membranes.
Stability
Lipogenesis is an ________- regulated process through which _____ is converted to ______, which are subsequently esterified to ________ to form the TAGs that are packaged in ________ and secreted from the liver.
Insulin Glucose Fatty acids Glycerol VLDL
_________ primarily transport dietary lipids, and _______ transports endogenously synthesized lipids.
Chylomicrons
VLDL
Produced in intestinal epithelial cells from dietary fat
Carries triacylglycerol in blood
Chylomicrons
Produced in liver mainly from dietary carbohydrate
Carries triacylglycerol in blood
VLDL
Very low density lipoprotein
Produced in blood ( remnant of VLDL after triacylglycerol digestion)
Endocytosed by liver or converted to LDL.
IDL
Intermediate density lipoprotein
Produced in blood ( remnant of IDL after triacylglycerol digestion, end product of VLDL)
Contains high concentration of cholesterol and cholesterol esters
Endocytosed by liver and peripheral tissues
LDL
Low density lipoprotein
Produced in liver and intestine
Exchanges proteins and lipids with other lipoproteins
Functions in the return of cholesterol from peripheral tissues to the liver
HDL
High density lipoprotein
TAGs are the major fat in the human diet, consisting of three _____ _____ esterified to a ______ backbone
Fatty acids
Glycerol
When partially digested food enters the intestine , the hormone _________ is secreted by the intestine, which signals the gallbladder to contract and release bile acids, and the pancreas to release digestive enzymes.
Cholecystokinin
Some cholesterol in the diet is not free cholesterol, it is hydrolyzed by the enzyme
Cholesterol esterase
Phospholipids in the diet are hydrolyzed by the enzyme
Phospholipase A2
