a family of compounds that includes triglycerides, phospholipids, and sterols. characterized by their insolubility in water
lipids
every triglyceride contains:
1 glycerol molecule
3 fatty acids
Fatty acids may be ____ to ____ (even numbers of) carbons long
4 to 24
the _____ carbon fatty acids are the most common in foods and especially noteworthy in nutrition
18
fatty acids are either ____________ or ____________
saturated or unsaturated
What are the 2 points of unsaturation for an unsaturated fatty acid
1. monounsaturated
2. polyunsaturated
What are the 2 important polyunsaturated fatty acids?
omega-3
omega-6
18-carbon polyunsaturated fatty acids (omega-3 and omega-6), both are essential fatty acids that the body cannot make. each is a primary member of a family of longer-chain fatty acids that help to regulate blood pressure, blood clotting, and other bodily
linolenic acid (omega-3) and lenoleic (omega-6)
a chain of carbon and hydrogen atoms with an acid group (COOH) at one end and a methyl group (CH3) at the other end?
fatty acids
most naturally occurring fatty acids contain _______ of carbons in their chains--up to ________ chains in length
even, 24
what foods contain the most common long-chain (12-24 carbons) fatty acids in the diet?
meats, seafood, and vegetable oils
what foods contain the smaller amounts of medium chain (6-10 carbons) and short chain (fewer than 6 carbons) ?
dairy products
a fatty acid carrying the maximum possible number of hydrogen atoms; contains only single bonds between its carbon atoms?
saturated fatty acid
the double bond of a fatty acid, where hydrogen atoms can easily be added to the structure
point of unsaturation
a fatty acid that lacks hydrogen atoms and has at least one double bond between carbons
unsaturated fatty acid
a fatty acid that lacks 2 hydrogen atoms and hose one double bond between carbons (olive and canola oil)
monounsaturated fatty acid
a fatty acid that lacks 4 or more hydrogen atoms and has 2 or more double bonds between carbons (vegetable oils)
polyunsaturated fatty acid
an essential fatty acid with 18 carbons and 3 double bonds
linolenic acid
an essential fatty acid with 18 carbons and 2 double bonds
linoleic acid
a polyunsaturated fatty acid in which the closest double bond to the methyl end of the carbon is three carbons away
omega-3 fatty acid
a polyunsaturated fatty acid in which the closest double bond to the methyl end of the carbon chain in 6 carbons away
omega-6 fatty acid
a chief form of fat in the diet and the major storage form of fat in the body; composed of a molecule of glycerol with 3 fatty acids attached
triglycerides
an alcohol composed of a 3-carbon chain, which can serve as the backbone for a triglyceride
glycerol
most polyunsaturated vegetable oils are ___________ at room temperature
liquid
the more saturated animal fats are _______________
solid
some oils--notably, cocoa butter, palm oil, palm kernel oil, and coconut oil--are ____________ they are firmer than most vegetable oils because of their _____________, but softer than most animal fats because of their shorter carbon chains (8 to 14 carbon
saturated; saturation
the shorter the carbon chain, the _________ the fat is at room temperature
softer
lipids that are solid at room temperature
fats
lipids that are liquid at room temperature
oils
the process of a substance combining with oxygen; involves the loss of electrons. all fats become spoiled when exposed to oxygen; produces a variety of compounds that smell and taste rancid
oxidation
1.______________ fats spoil most readily, because their double bonds are unstable
2. _____________ fats are slightly less susceptible
3. _____________ fats are most resistant to oxidation and thus least likely to become rancid
polyunsaturated
monounsaturated
saturated
as a food additive, preservatives that delay or prevent rancidity of fats in food and other damage to food caused by oxygen
antioxidants
a chemical process by which hydrogens are added to MUFA and PUFA to reduce the number of double bonds, making the fats more saturated (solid) and more resistant to oxidation. produces "trans-fatty acids
hydrogenation
on the near side of; refers to a chemical configuration in which the hydrogen atoms are located on the same side of a double bond
cis (most common in nature)
on the other side of; refers to a chemical configuration in which the hydrogen atoms are located on the opposite sides of a double bond
trans
fatty acids with hydrogens on opposite sides of the double bond
trans-fatty acids
a compound similar to a triglyceride but having a phosphate group and choline in place of one of the fatty acids
phospholipid
best known phospholipid, both nature and food industry use it as an emulsifier to combine water-soluble and fat-soluble ingredients that do not ordinarily mix, such as water and oil
lecithin
these fatty acids make phospholipids soluble in fat
hydrophobic
this phosphate group allows them to dissolve in water
hydrophilic
compounds containing a four-ring carbon structure with any of a variety of side chains attached
sterols
most famous sterol
cholesterol
more than 90% of the body's cholesterol is found in the _______________
cells
foods derived from plants and animals contain ___________, only those from ____________ contain significant amounts of cholesterol
sterol; animal
cholesterol made in the body
endogenous
cholesterol from outside of the body
exogenous
enzymes that hydrolyze lipids
lipases
the main goal of fat digestion is to dismantle triglycerides into what small molecules?
1. monoglycerides
2. fatty acids
3. glycerol
what enzyme released by the salivary gland at the base of the tongue plays an active role in the fat digestion of infants
lingual lipase
the actions of the stomach help expose the fat for attack by what enzyme?
gastric lipase enzyme
when fat enters the small intestine, it triggers the release of what hormone, which signals the gallbladder to release its stored bile
cholecystokinin (CCK)
bile in the small intestine acts as an ______________, because the amino acid end is ____________ and the sterol end is _______________
1. emulsifier
2. hydrophilic
3. hydrophobic
most of the hydrolysis of triglycerides occurs where?
small intestine
what are the main fat digesting enzymes?
pancreatic lipases
small molecules (glycerol and medium chain fatty acids) can diffuse easily into the intestinal cells; larger molecules (monoglycerides and long chain fatty acids) are emulsified by bile, forming spherical complexes known as
micelles
clusters of lipids associated with proteins that serve as transport vehicles for lipids in the lymph and blood
lipoproteins
the largest and least dens of the lipoproteins, transport "diet derived lipids (mostly triglycerides) from the small intestine to the rest of the body
chylomicrons
the type of lipoprotein made primarily by liver cells to transport lipids to various tissues in the body; composed primarily of triglycerides
VLDL (very-low density lipoprotein)
the type of lipoprotein derived from (VLDL) as triglycerides are removed and broken down composed primarily of cholesterol
LDL (low-density lipoprotein)
the type of lipoprotein that transports cholesterol back tot he liver from cells; composed primarily of protein. lowers the risk of heart disease
HDL (high-density lipoprotein)
High _________ cholesterol is associated with a high risk of heart attack; whereas high __________ cholesterol seems to have a protective effect
LDL, HDL
What role do lipids play in the body?
1. insulate against temp. extremes
2. protect against shock
3. maintain cell membranes
____________ provide cells with energy
triglycerides
fat provides more than _____________ the energy of CHO and protein
twice
the body's fat tissue; consists of mass of triglyceride-storing cells
adipose tissue
proteins synthesized and secreted by adipose cells, help regulate energy balance and influence several bodily functions
adipokines
Name the 2 essential fatty acids the body cannot make?
1. (18-carbon omega-6 fatty acid)
2. (18-carbon omega-3 fatty acid)
the fatty acids needed by the body but not made by it in amounts sufficient to meet physiological needs
essential fatty acids
what foods contain omega-6 and 3?
vegetables oils, seeds, nuts, fish, other seafoods
_____________ acid is the primary member of the omega-6 fatty acid family
linoleic
_____________ acid is the primary member of the omega-3 fatty acid family
linolenic
these omega 3 fatty acids are found in the eyes and brain and are essential for normal growth, visual acuity, and cognitive development (both found in fatty fish)
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
derivatives of 20-carbon fatty acids; biologically active compounds that help to regulate blood pressure, blood clotting, and other bodily functions
eicosanoids
an enzyme that hydrolyzes triglycerides passing by in the bloodstream and directs their parts into the cells, where they can be metabolized for energy or reassembled for storage
lipoprotein lipase (LPL)
fat supplies about __________ percent of the body's ongoing energy needs during rest.
60
an enzyme inside adipose cells that responds to the body's needs for fuel by hydrolyzing triglycerides so that their parts (glycerol and fatty acids) escape into the general circulation and thus become available to other cells of fuel. the signals to whic
hormone-sensitive lipase
elevated LDL cholesterol may cause this; diseases of the heart and blood vessels throughout the body. Atherosclerosis is the main cause of CVD. When the arteries that carry blood to the heart muscle become blocked, the heart suffers damage known as corona
cardiovascular disease (CVD)
number 1 killer of adults
heart disease
major sources of cholesterol
1. eggs
2. milk and milk products
3. meat, poultry, shellfish