Lipids - Chapter 6 Flashcards
Lipids
Substances soluble in organic solvents
Hydrophobic
“Water-hating” “water-fearing”
Repelled by water
Lipophillic
Lipids are lipophillic
“fat loving”
attracted by lipid
Where is most of the lipid stored?
In the bodies of animals
Organic
- A complex chemical containing carbon in its structure.
- Often formed in a bioogical process
What form is most inorganic carbon in?
Carbon dioxide in the atmosphere
Three kinds of lipids
- Triglycerides
- Phospholipids
- Sterols
Triglyceride
- A type of lipid formed by three fatty acids arrayed on a glycerol backbone
- Most fats occur in the triglyceride form
Phospholipid
- A type of lipid similar to a triglyceride in which one of the fatty acids is replaced by a phosphorous-containing compound
Sterol
- A type of lipid with a multiple ring structure, such as cholesterol
Fatty acid
- A lipid formed of a chain of carbon atoms, saturated by hydrogen atoms to varying degrees, with a methyl group on one end and a carboxyl group on the other
Methyl
- the omega end
- the chemical group -CH3
Carboxyl
- alpha end
- the chemical group -COOH
Valence
The characteristic number of chemical bonds formed by a particular chemical element
Valence of hydrogen
1
Valence of oxygen
2
Valence of carbon
4
Saturated fatty acid (SFA)
A fatty acid in which all of the carbon-carbon bonds are single bonds. It is saturated with hydrogen atoms, that is, it contains all the hydrogen it can in its structure
Found in animal products
Butryic (4C) Caprylic (8C) and stearic (18C)
Acids that are typical of saturated fatty acids
Saturated fats worst
Worst dietary contributor to the development of heart disease
point of unsaturation
A double bond in a fatty acid.
Not saturated by hydrogen atoms; more hydrogen could be added where the double bond is to be split
Monounsaturated Fatty Acid (MUFA)
A fatty acid containing a single point of unsaturation, that is, a single double bond, in its structure
Found in vegetable fats including Olive oil
Lower freezing point
liquid at room temperature - cloud or get stiff if in refrigerator
Oleic acid (18C)
Makes up most of olive oil (a MUFA)
Saturated fats raise what?
Blood cholesterol
Other examples of monounsaturated fats
Canola oil, sesame oil, walnut oil, and avocado oil
lowers blood levels of cholesterol and are not associated with an increased risk of disease
polyunsaturated fatty acid (PUFA)
A fatty acid containing more than one point of unsaturation, that is, more than one doulbe bond
Found in vegetable fats
2-6 double bonds
stay liquid in freezer
18:3 fatty acid
18 carbons with 3 double bonds
Examples of saturated fatty acids
Coconut oil
Butter
Palm oil
Lard or beef fat
Examples of monounsaturated fatty acids
Olive oil
Canola oil - also rich in omega-3
Peanut oil
Soybean oil - also rich in omega-3
Linoleic acid
An 18:2 omega-6 polyunsaturated fatty acid
An essential fatty acid
Omega-6 Polyunsaturates
Most common vegetable oils
Corn, safflower, soybean, cottonseed, and sunflower
Lower both the desirable and undesirable types of cholesterol so = mixed blessing in heart disease prevention
Eicosapentanoic acid
A 20:5 omega-3 polyunsaturated fatty acid.
Found in fish
Docosahexanoic acid
A 22:6 omega-3 polyunsaturated fatty acid
Found in fish
Omega-3’s are mainly:
Fish oils
Omega-3 can also occur in what:
Plants as alpha-linolenic acid (18:3)
found in flax, canola, soy, and other oils
fat is converted to EPA in body
Lower risk of heart attack
Alpha-linolenic acid
An 18:3 omega-3 fatty acid.
Essential fatty acid
Found in flax, canola, and soy oils
Fats consist of a mixture of fatty acids but one particular fatty acid usually dominates
Increasing saturation
raises the melting point of a fat
Saturated fats get
stiff at low temperatures