Lipids: Fats

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Lipids Fats Oils
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• Lipids

energy storage
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Lipids

• Lipids are composed of C, H, O
• long hydrocarbon chain
• Diverse group
• fats
• phospholipids
• steroids
• Do not form polymers
• big molecules made of smaller subunits
• not a continuing chain

fat
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Fat subunits

• Structure
• glycerol (3C alcohol) fatty acid

• fatty acid long HC tail with COOH group at
  head

dehydration synthesis
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Building Fats

• Triacylglycerol
• 3 fatty acids linked to glycerol
• ester linkage between OH COOH

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Dehydration synthesis
dehydration synthesis
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Fats store energy
Why do humanslike fatty foods?

• Long HC chain
• polar or non-polar?
• hydrophilic or hydrophobic?
• Function
• energy storage
• very rich
• 2x carbohydrates
• cushion organs
• insulates body
• think whale blubber!

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Saturated fats

• All C bonded to H
• No CC double bonds
• long, straight chain
• most animal fats
• solid at room temp.
• contributes to cardiovascular disease
  (atherosclerosis) plaque deposits

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Unsaturated fats

• CC 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?
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Saturated vs. unsaturated
saturated
unsaturated
?
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Phospholipids

• Structure
• glycerol 2 fatty acids PO4
• PO4 negatively charged

Its just like apenguin A head at one end a
tail at the other!
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Phospholipids in water

• Hydrophilic heads attracted to H2O
• Hydrophobic tails hide from H2O
• can self-assemble into bubbles
• bubble micelle
• can also form bilayer
• early evolutionary stage of cell?

bilayer
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Why is this important?

• Phospholipids create a barrier in water
• define outside vs. inside
• cell membranes

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Phospholipids cells

• Phospholipids of cell membrane
• double layer bilayer
• hydrophilic heads on outside
• in contact with aqueous solution outside of cell
  and inside of cell
• hydrophobic tails on inside
• form core
• forms barrier between cell external environment

Tell themabout soap!
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Steroids

• ex cholesterol, sex hormones
• 4 fused C rings
• different steroids created by attaching different
  functional groups to rings

cholesterol
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Cholesterol

• Important cell component
• animal cell membranes
• precursor of all other steroids
• including vertebrate sex hormones
• high levels in blood may contribute to
  cardiovascular disease

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Cholesterol
Important component of cell membrane

• helps keep cell membranes fluid flexible

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From Cholesterol ? Sex Hormones

• What a big difference a few atoms can make!

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• Lets build some
• Lipids!