Transcript 9. Lipids PPT

Lipids
Macromolecule #2: Lipids
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Hydrophobic (nonpolar) = insoluble in water
Contain C, H, O (less O than carbs), sometimes P
Main types:
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Triglycerides (fats & oils)
Phospholipids
Steroids
1. Triglycerides (fats & oils)
Saturated = each C
has 4 single covalent
bonds with H
Unsaturated =
presence of one or
more double bonds
Contain glycerol + three fatty acids
FUNCTIONS: Energy storage, cushioning, insulation
The bad saturated fat
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Large amounts of saturated Found in fats of mostly
animal origin
fat increase the risk of heart
disease
↑ both LDL (“bad”
lipoprotein) & HDL
(“good” lipoprotein)
LDL may deposit cholesterol
on arteries; HDL carries
cholesterol from blood to
liver where it may be stored
Unsaturated oils = the good lipids
Found in olive oil, canola oil, peanut oil, fish
oil, nuts
↓ LDL (bad lipoprotein)
Hydrogenated fats = the worst guys
Also called trans fats; hydrogens are added
synthetically to unsaturated oils to make them
solids at room T
margarine, crisco
↑ LDL and ↓ HDL
2. Phospholipids
Found in cell membranes
3. Steroids
Functions of cholesterol:
1. Increases stability of all animal cell membranes
2. Needed to make bile (bile is needed for digestion of
fats)
3. Precursor to steroid hormones, e.g. testosterone,
estrogen, calcitriol
4. Other Lipids
Eicosanoids – “local hormones”; LOTS of functions:
 Contribute to inflammatory and immune response
 Control other hormones
 Prevent stomach ulcers
 Regulate body T
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Influence formation of blood clots
Derived from omega-3 and omega-6 essential fatty acids