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