UNIT 6 Flashcards
The Lipids
Lipids
A family of organic compounds soluble in organic solvents but not in water. Lipids include triglycerides (fats and oils), phospholipids, and sterols.
Triglycerides
Make up roughly 95% of lipids in foods and the human body, and is one of the three primary dietary lipids.
Defined as: The chief form of fat in foods and the human body. Is made up of 3 units of fatty acids and one unit of glycerol.
Also referred to as: “triacylglycerols”
phospholipids
Another of the three dietary lipids. They have the ability to attract water-soluble as well as fat soulbe substances; they can facilitate the passage of fats in and out of cells through the membranes .
These are present in all cell membranes.
Lecithin (LESS-ih-thin)
a phospholipid manufactured by the liver and also found in many foods.
It is a major constituent of cell membranes.
Sterols
A lipid with a characteristic hydrocarbon ring structure; all sterols are derived from cholesterol.
What are the three main classes of lipids?
triglycerides
phospholipids
Sterols
What are three uses of fat in the body?
Energy Storage
Muscle Fuel
Emergency Reserve
What are three uses of fats in food?
Nutrients as fatty acids
Sensory Appeal
Energy (fat contains concentrated energy in calories)
What are essential fatty acids
Fatty acids that the body needs but cannot make in amounts sufficient to meet physiological needs.
General Question: What is the amount of calories provided by 1g of carbohydrates, lipids, and proteins respectively?
1g Carbs= 4 Cal
1g Lipid= 9 cal
1g protein= 4 cal
Satiety (sat-EYE-uh-tee)
The feeling of fullness or satisfaction that people experience after a meal
How does fat contribute to the feeling of Satiety
The fat of swallowed food triggers a series of physiological events that slow down the emptying of the stomach and promote this feeling.
Fatty Acids
organic acid composed of carbon chains of various lengths. Each fatty acid has an acid end and hydrogens attached to all the carbon atoms of the chain
glycerol
An organic compound, three carbons long, of interest here because it serves as the backbone for triglycerides.
Saturated Fatty Acids (SAFA)
a fatty acid carrying the maximum possible number of hydrogen atoms (having no points of unsaturation)
What are the three types of fatty acids
Saturated
monounsaturated
polyunsaturated
point of unsaturation
a site in a molecule where the bonding is such that additional hydrogen atoms can easily be attached
Unsaturated fatty acid
a fatty acid that lacks some hydrogen atoms and has one or more points of unsaturation. An unsaturated fat is a triglyceride that contains one or more unsaturated fatty acids.
monounsaturated fatty acid (MUFA)
a fatty acid containing one point of unsaturation
polyunsaturated fatty acid (PUFA)
a fatty acid with two or more points of unsaturation
Saturated fats
triglycerides in which most of the fatty acids are saturated
trans-fat
fats that contain unusual fatty acids; trans fatty acids are largely formed during processing.
monounsaturated fats
triglycerides in which most of the fatty acids have one point of unsaturation
Emulsifier
a substance that mixes both fat and water and permanently disperses the fat in the water, forming an emulsion
Emulsification
the process of mixing lipid with water by adding an emulsifier
Bile
an emulsifier made by the liver from cholesterol and stored in the gallbladder. Bile does not digest fat as enzymes do.
but emulsifies it so that enzymes in the watery fluids may contact it and split the fatty acids from their glycerol for absorption
Endogenous cholesterol
The 80% of the body’s cholesterol that is synthesized by the body (mostly live)
Exogenous Cholesterol
This is cholesterol from dietary sources, and is the other 20% of the bodys cholesterol
What are the 3 classifications of fatty acids according to chain length
Short-Chain fatty acids: 4-8 carbons
Medium-chain fatty acids: 10-14 carbons
Long-Chain fatty acids: 16-22 carbons
What are the 3 classifications of fatty acids according to double bonds?
Saturated Fatty acids: No D.Bond
Monounsaturated Fatty Acids: 1 D.Bond
Polyunsaturated fatty acids: 2 D.Bonds.
Very low-density lipoproteins (VLDL)
A lipoprotein that carries triglycerides and other lipids made int he liver to the body cells for use
Low Density lipoproteins (LDL)
These transport cholesterol and other lipids to the tissues. LDL are made from VLDL after they have donated many of their triglycerides
These deliver triglycerides and cholesterol from the liver to tissues
High Density lipoproteins (HDL)
Which are critical in the process of carrying cholesterol away from body cells to the liver for disposal
These scavenge excess cholesterol and phospholipids from the tissues for disposal
What are the four main lipoproteins
chylomicrons, VLDL, LDL, HDL.
Oxidation
Interaction of a compound with oxygen, a damaging effect by a chemically reactive form of oxygen
Dietary antioxidant
A substance in food that significantly decreases the damaging effects of reactive compounds, such as reactive forms of oxygen and nitrogen on tissue functioning.
Linoleic (lin-oh-LAY-ic) Acid, and Linolenic (lin-oh-LEN-ic) acid
These are Omega 6 and Omega 3 fatty acids.
they are both polyunsaturated fatty acids that are essential nutrients for human beings.
eicosanoids (eye-COSS-ah-noyds)
biologically active compounds that regulate body functions.
Chylomicrons
Lipoproteins formed in the mucosal cells after absorption of dietary lipids.
Composed mainly of triglycerides and are very low density.
How does VLDL become LDL
VLDL is carried to other parts of the body where cells will remove the triglycerrides and use them for energy, or storage.
This removal converts the VLDL to LDL
Hydrogenation
The process of adding hydrogen to unsaturated fatty acids to make fat more solid and resistant to the chemical change of oxidation
Smoking Point
The temperature at which fat gives off an acrid blue gas
Trans fatty acids
Fatty acids with unusual shapes that can arise when polyunsaturated oils are hydrogenated.
Commonly referred to as transfat
Why are trans fatty acids (trans-fats) harmful
When consumed, these fats raise the body’s LDL and lower the body’s HDL
This poses a risk to the function of the heart and artery and higher concentrations of LDL can narrow the arterial pathways.
Artificial fats (Fat analogues)
0 energy fats replacers that are chemically synthesized to mimic the sensory and cooking qualities of naturally occurring fats but are totally or partially resistant to digestion.
fat replacers (Fat substitutes)
Ingredients that replace some of all of the functions of fat and may or may not provide energy.
olestra
a noncaloric artificial fat made from sucrose and fatty acid
sucrose polyster
any of a family of compounds in which fatty acids are bonded with sugars or sugar alcohols.
Olestra is an example of a sucrose polyester
Which of these fatty acids is NOT an omega 3
Linoleic Acid
Linolenic Acid
DPA
EHA
Linoleic Acid
vegetable oils are liquid because?
They contain a large amount of short-chain fatty acids
Where does digestion of lipids usually occur?
Almost exclusively in the small intestine
What is the result of the Emulsification of dietary lipids
It disperses and suspends fat droplets in a watery solution.
After absorption into the muscosal cells, long chain fatty acids do what?
Reassemble and form new triglycerides
Which of these lipoproteins can carry dietary lipids to the liver?
VLDL, LDL, HDL, or Chylomicrons
Chylomircons
What is the most important function of lipids in the body
Providing energy
What vitamin is synthesized from cholesterol
Vitamin D
A fat that is hydrogenated has some double bonds in what form?
The trans form
A fat that has been oxidized loses what?
EFA because double bonds have been changed in the process.
What are the tiny spherical complexes that absorb free fatty acids and monoglycerides into mucosal cells called?
Micelles
How does the chemical composition of animal fats differ from that of fats originating from plants
Animal fats tend to contain large amount of saturated fatty acids, palmitic acid and stearic acids
Plant fats tend to contain the unsaturated fats, oleic acid, and linoleic acid.
