ap biology lipids: fats & oils & wax & steroid ap biology lipids lipids are composed of...
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AP Biology
Lipids Lipids are composed of C, H, O 4 groups:
fats oils waxes steroids
Do not form polymers big molecules made of smaller subunits not a continuing chain
AP Biology
Lipids Six functions of lipids:1. Long term energy storage2. Protection against heat loss (insulation)3. Protection against physical shock4. Protection against water loss5. Chemical messengers (hormones)6. Major component of membranes (phospholipids)
AP Biology
Fats store energy Function:
energy storage 2x energy of
carbohydrates cushion organs insulates body
think whale blubber!
Why do humanslike fatty foods?
AP Biology
Fat subunits Structure:
glycerol (3C alcohol) + fatty acid
dehydration synthesis
fatty acid = long “tail” with COOH group at “head”
Fatty Acid Structure
• Carboxyl group (COOH) forms the acid.• “R” group is a hydrocarbon chain (chain of hydrogens and carbons).
Hydrophilic vs hydrophobicHydrophilic – Water loving – soluble in waterHydrophobic – water hating – is NOT soluble in water
Triglyceride =1 glycerol, 3 fatty acids Hydrophilic
Phospholipids = 1 glycerol, 2 fatty acids 1 phosphate group tails are hydrophobic the heads are hydrophilic. make up cell membranes
AP Biology
Saturated fats All C bonded to H No C=C double bonds
long, straight chain most animal fats solid at room temp.
contributes to cardiovascular disease (atherosclerosis) = plaque deposits
AP Biology
Unsaturated fats C=C double bonds in
the fatty acids plant & fish fats vegetable oils liquid at room temperature
the kinks made by doublebonded C prevent the molecules from packing tightly together
mono-unsaturated?poly-unsaturated?
AP Biology
If fatty acids are unsaturated, their shape is altered from a saturated molecule so the molecules in the Lipid push apart, thus making it more fluid and oily.
Animals tend to have more saturated, and consequently solid at room temperature lipids
whereas plants tend to have more unsaturated and so fluid at room temperature lipids
AP Biology
Waxes
• Ear wax – protection from foreign materials/ invaders (such as insects)
• Wax coating on leaves – forms a barrier to keep water in leaves
AP Biology
Steroids
Cholesterol Found in cell membranes – keeps them
flexible Hormones (chemical messengers)
AP Biology
Quiz1. What are the four types of lipids ?
2. Name as many functions of lipids as possible (6).
3. What is the difference in saturated & unsaturated ?
4. How could you tell the difference in saturated & unsaturated by looking at an item ?
5. What is healthier, saturated or unsaturated fats ?
6. Lipids contain more energy than carbs, so why are carbs are primary energy source ?
7. What is the monomer & polymer of lipids ?
8. Structurally, how do you tell the difference in carbs & lipids ?
AP Biology
Answers1. Fats, oils, waxes, & steroids
2. Energy storage, insulation, protection from water loss, protection against physical shocks, chemical messengers, component of cell membranes
3. C=C double bonds are in unsaturated
4. Saturated are solid at room temp., unsaturated are liquid at room temp.
5. unsaturated
6. Lipids are harder to break down, because they are insoluble in water
7. Technically, there are not monomers & polymers
8. Both contain C,H, & O, but in carbs they are in a 1:2:1 ratio
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