NUTR 331 Unit 6 Study Questions with 100%
Correct Answers
Triglycerides
one of the three main classes of dietary lipids and the chief form of fat in foods and in the
human body. A triglyceride is made up of three units of fatty acids and one unit of glycerol.
- lipid composed of a glycerol molecule - attached are three fatty acids (organic acids consisting
of hydrocarbon chains)
- each chain has a carboxylic acid at one end and a methyl group at the other
- if only one fatty acid is attached to a glycerol molecule, a monoglyceride is formed - if two, a
diglyceride
- monoglycerides & diglycerides are used by food processors - they act as emulsifiers; give a
smooth texture and keep fats evenly dispersed (ice cream, baked goods, margarine, lard,
shortening)
- monoglycerides can also be found in human GI tract after a fatty meal - product of fat
digestion
Describe lipids
- Lipids are compounds composed primarily of carbon, hydrogen, and small amounts of oxygen
- Lipids are insoluble in water
Fat is a subgroup of lipids
Phospholipids
one of the three main classes of dietary lipids. These lipids are similar to triglycerides, but each
has a phosphorus-containing acid in place of one of the fatty acids. Phospholipids are present in
all cell membranes.
- have ability to attract water-soluble AND fat-soluble triglycerides and sterols
- have the ability to attract water soluble and fat-soluble substances
- this helps facilitate passage of fats in and out of cells through cell membranes
- in the blood and body fluids they are emulsifiers, keeping fats in solution
, - lecithin occurs naturally in liver, egg yolk, and soybeans - serves as an emulsifier in foods like
processed cheese, margarine, candy, and chocolate bars
- when ingested, phospholipids are hydrolyzed by intestinal enzymes & can be used to produce
energy
- they are not an essential nutrient because the body can synthesize them
- Emulsifier - a substance that mixes with both fat and water and permanently disperses the fat
in the water, forming an emulsion
- Emulsification - the process of mixing liquid with water by adding an emulsifier (example: the
emulsifier lecithin in egg yolk to make mayo)
- Phospholipids play a role in the structure of cell membranes - because they are emulsifiers
they have fat-loving and water-loving characteristics
- This helps them move fats back and forth across cell membranes into the watery fluid on both
sides of the cell
Sterols
- one of the three main classes of dietary lipids. Sterols have a structure similar to that of
cholesterol.
- lipid with a characteristic hydrocarbon ring structure
- all sterols are derived from cholesterol
- they resemble chicken wire
- not soluble in water
- do not contribute energy to body
- endogenous cholesterol - about 80% of cholesterol is synthesized in the body (mainly by liver)
- exogenous cholesterol - cholesterol from dietary sources (contributes the other 20%)
- all cholesterol is of animal origin
- adult intake of cholesterol (per day) is 200 to 400 mg
- Large, complicated molecules consisting of interconnected rings of carbon atoms w/ side
chains of carbon, hydrogen, and oxygen attached
- Cholesterol, a sterol, is the raw material for making another emulsifier, bile
- Other sterols include vitamin D, which is made from cholesterol, and steroid hormones
Correct Answers
Triglycerides
one of the three main classes of dietary lipids and the chief form of fat in foods and in the
human body. A triglyceride is made up of three units of fatty acids and one unit of glycerol.
- lipid composed of a glycerol molecule - attached are three fatty acids (organic acids consisting
of hydrocarbon chains)
- each chain has a carboxylic acid at one end and a methyl group at the other
- if only one fatty acid is attached to a glycerol molecule, a monoglyceride is formed - if two, a
diglyceride
- monoglycerides & diglycerides are used by food processors - they act as emulsifiers; give a
smooth texture and keep fats evenly dispersed (ice cream, baked goods, margarine, lard,
shortening)
- monoglycerides can also be found in human GI tract after a fatty meal - product of fat
digestion
Describe lipids
- Lipids are compounds composed primarily of carbon, hydrogen, and small amounts of oxygen
- Lipids are insoluble in water
Fat is a subgroup of lipids
Phospholipids
one of the three main classes of dietary lipids. These lipids are similar to triglycerides, but each
has a phosphorus-containing acid in place of one of the fatty acids. Phospholipids are present in
all cell membranes.
- have ability to attract water-soluble AND fat-soluble triglycerides and sterols
- have the ability to attract water soluble and fat-soluble substances
- this helps facilitate passage of fats in and out of cells through cell membranes
- in the blood and body fluids they are emulsifiers, keeping fats in solution
, - lecithin occurs naturally in liver, egg yolk, and soybeans - serves as an emulsifier in foods like
processed cheese, margarine, candy, and chocolate bars
- when ingested, phospholipids are hydrolyzed by intestinal enzymes & can be used to produce
energy
- they are not an essential nutrient because the body can synthesize them
- Emulsifier - a substance that mixes with both fat and water and permanently disperses the fat
in the water, forming an emulsion
- Emulsification - the process of mixing liquid with water by adding an emulsifier (example: the
emulsifier lecithin in egg yolk to make mayo)
- Phospholipids play a role in the structure of cell membranes - because they are emulsifiers
they have fat-loving and water-loving characteristics
- This helps them move fats back and forth across cell membranes into the watery fluid on both
sides of the cell
Sterols
- one of the three main classes of dietary lipids. Sterols have a structure similar to that of
cholesterol.
- lipid with a characteristic hydrocarbon ring structure
- all sterols are derived from cholesterol
- they resemble chicken wire
- not soluble in water
- do not contribute energy to body
- endogenous cholesterol - about 80% of cholesterol is synthesized in the body (mainly by liver)
- exogenous cholesterol - cholesterol from dietary sources (contributes the other 20%)
- all cholesterol is of animal origin
- adult intake of cholesterol (per day) is 200 to 400 mg
- Large, complicated molecules consisting of interconnected rings of carbon atoms w/ side
chains of carbon, hydrogen, and oxygen attached
- Cholesterol, a sterol, is the raw material for making another emulsifier, bile
- Other sterols include vitamin D, which is made from cholesterol, and steroid hormones
