Chapter 6: Lipids,
Functions of phospholipids in the body:
-needed for normal functioning of nerve cells -form lipid bilayer of cell membranes -aid in fat digestion and absorption
Functions of cholesterol:
-synthesis of certain bile acids -synthesis of certain hormones -incorporation into cell structures
What are the structural components of a triglyceride?
-three attached fatty acids -glycerol backbone
Modifiable risk factors for CVD:
-Hypertension -Tobacco use -Type 2 Diabetes -Excess body fat
Which fatty acids are considered essential fatty acids?
-alpha-linolenic acid -linolenic acid
Fat digestion is rapid and thorough in the small intestine under what "right" circumstances?
-bile from the gallbladder is present -lipase breaks triglycerides down to monoglycerides
Process of enterohepatic circulation
-bile salts are absorbed in the ileum of the small intestine -bile salts travel through the blood to the liver -the liver recycles used bile salts to make new bile.
Glycerol
3-carbon alcohol that forms the "backbone" of fatty acids. Circulates back to the liver
Medium-chain fatty acids have how many carbons?
6-12 carbons
Lipids
Class of nutrients that do not dissolve in water (insoluble); Include triglycerides, phospholipids, and sterols (cholesterol)
Essential Fatty Acids
Fatty acids that must be supplied by the diet; linoleic and alpha-linolenic acid are essential fatty acids
What are the by-products of lipid digestion?
Glycerol and Fatty acids
Fatty Acids
Hydrocarbon chain found in lipids; Provide energy for muscle and other cell types; One end of the chain forms a carboxylic acid, and one end forms a methyl group
Where are the small chylomicrons cleared from the bloodstream and used to synthesize new lipids and other lipoproteins?
Liver
Alpha-linolenic Acid
Omega-3 Fatty Acid; 18-carbon polyunsatu-rated fatty acid with three double bonds; an essential fatty acid
Linoleic Acid
Omega-6 Fatty Acid; 18-carbon polyunsaturated fatty acid with two double bonds; an essential fatty acid
Food manufactures use the process of hydrogenation to:
convert liquid oils into more solid fats
Cis fatty acid
hydrogen ions at the double bond (same side)
All lipid molecules are
insoluble in water
In a healthy person, the liver synthsizes _______ cholesterol when dietary cholesterol intake is higher.
less
What does the hydrogenation process do?
produces trans fats
A ______________ fatty acid is completely filled with hydrogen atoms
saturated
Cholesterol lowering margarine's contain plant _________, which may lower cholesterol in people with mildly elevated cholesterol levels
sterols
Which form of unsaturated fatty acid contains a chemical structure similar to that of saturated fatty acids?
trans
What are the products of fat digestion in the small intestine?
-fatty acids -monoglycerides -glycerol
Monounsaturated Fatty Acid (MUFA)
Fatty acid that has only one double bond within the carbon chains
Unsaturated Fatty Acid
Fatty acid that is missing hydrogen atoms and has one or more double bonds within the carbon chain
Carboxylic Acid
Organic molecule with a carboxyl (—COOH) group
What can consuming high amounts of certain lipids increase the risk of?
Obesity, certain cancers, and cardiovascular disease (CVD) including heart disease and stroke
What are the 7 major functions of Lipids?
1) Provide and store energy (triglycerides) 2) Form and maintain cell membranes 3) Produce steroid hormones 4) Insulate the body against cold temperatures 5) Cushion the body against bumps and blows 6) Form body contours 7) Absorb fat-soluble vitamins and phytochemicals
The AI of alpha-linoleic acid for men is (19-50yrs old) is _______ and for women is _________
1.6g/day; 1.1 g/day
Long-chain fatty acids have how many carbons?
14-24 carbons
Oleic Acid
18-carbon monounsaturated fatty acid
Short-chain fatty acids have how many carbons?
2-4 carbons
Free fatty acids
Absorbed by cells within the vicinity and reform into trygliceride for storage or use.
Omega-3 Fatty Acid
Alpha-linolenic Acid; Type of polyunsaturated fatty acid with the first double bond at the third carbon from the omega end of the molecule. Decreases blood clotting and inflammation
Omega-6 Fatty Acid
Alpha-linolenic Acid; Type of polyunsaturated fatty acid with the first double bond at the third carbon from the omega end of the molecule. Increases blood clotting and inflammation
Why are the chemical structures of trans and saturated fatty acids similar?
Both contain a straight molecular structure
What is the difference between fats and oils?
Both have Fatty Acids; Fats tend to be solid and oils liquid at room temperature; Fats contain more long-chain saturated FAs; Oils contain more long-chain unsaturated FAs
Adipose (fat) cells
Cells that absorb fatty acids and glycerol from the blood and STORE TRIGLYCERIDES
Hydrocarbon Chain
Chain of carbon atoms bonded to each other and to hydrogen atoms
_________________ is only found in food that contains animal products
Cholesterol
Polyunsaturated Fatty Acid (PUFA)
Fatty acid that has two or more double bonds within the carbon chain
Pancreatic Lipase
Digestive enzyme that removes two fatty acids from each triglyceride molecule converting most triglycerides to monoglycerides and free fatty acids
Lipids will ______ in organic solvents such as alcohol and acetone, but most lipids are insoluble in water.
Dissolve
Omega (methly) End
End of a fatty acid containing a methyl (—CH3) group
Eicosapentaenoic acid (EPA)
Essential fatty acid; Converted from Alpha-Linoleic Acid and other Omega-6 FAs; Precursor to some eicosanoids; Required in infants for nervous system development
Arachidonic acid (AA)
Essential fatty acid; Converted from Linoleic Acid; Precursor to some eicosanoids
Docosahexaenoic acid (DHA)
Essential fatty acid; precursor to some eicosanoids; Required in infants for nervous system development
In biological systems, common fatty acids have a(n) _____ number of carbon atoms.
Even
Body parts most vulnerable to damage from atherosclerosis:
Legs, Kidneys, Eyes.
What are the 2 Essential Fatty Acids?
Linoleic Acid, Alpha-linolenic acid
Cholesterol
Lipid found in animal foods; Precursor for steroid hormones, bile, and vitamin D
What are the 3 major classes of lipids?
Triglycerides, Phospholipids, Sterols (cholesterol, vitamin D)
Fatty acids can be saturated or unsaturated. (TRUE/FALSE)
True
Artherosclerosis
a condition that can inhibit the blood flow and permenantly damage the kidneys, eyes, legs, heart, and brain.
Statins
a type of prescription drug that reduces a person's blood lipid levels
Fatty acids are always saturated (True or False)
False
Phospholipids are only found in fat cells (True/False)
False. Essential part of all body cells
Saturated Fatty Acid (SFA)
Fatty acid that has each carbon atom within the chain filled with hydrogen atoms
Lipid digestion process in the small intestine:
-fatty chyme stimulates the release of cholecystokinin -cholecystokinin signals the pancreas to secrete digestive enzymes -pancreatic lipase digests triglycerides and converts them to monoglycerides and 2 fatty acid molecules
Most foods contain fats with both saturated and unsaturated fatty acids. (TRUE/FALSE)
True