Lipids

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• Lipids

Fats
Oils
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Lipids Fats Oils
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Lipids

• Lipids are composed of C, H, O
• Not considered polymers-no subunits
• Family groups
• Fats
• Phospholipids
• Steroids
• Polymers
• big molecules made of smaller subunits
• not a continuing chain

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Fats

• Structure
• Glycerol and fatty acids
• fatty acid long HC tail with carboxyl (COOH)
  group head

dehydration synthesis
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Building Fats

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

hydroxyl
carboxyl
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Dehydration synthesis
dehydration synthesis
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Fats store energy

• Long HC chain
• polar or non-polar?
• hydrophilic or hydrophobic?
• Function
• Store Energy
• concentrated
• all H-C!
• 2x carbohydrates
• Cushioning
• Insulates
• think whale blubber!

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Saturated fats

• All C bonded to H
• No CC double bonds
• Solid at Room Temp.
• Butter
• Lard
• contributes to cardiovascular disease
  (atherosclerosis) plaque deposits

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Unsaturated fats

• CC double bonds in the fatty acids
• One or more double bonds
• Plant Fats
• Liquid at Room Temp.
• the kinks made by doublebonded C prevent the
  molecules from packing tightly together

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Saturated vs. unsaturated
_______________
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Phospholipids

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

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Phospholipids

• Hydrophobic or hydrophilic?
• fatty acid tails Hydrophobic
• PO4 head Hydrophilic
• split personality

attracted to water
interaction with H2O is complex very important!
repelled by water
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Phospholipids in water

• Tails repelled by water
• Heads attracted to water
• can self-assemble into bubbles
• bubble micelle
• can also form a Bilayer
• early evolutionary stage of cell?

water
bilayer
water
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Why is this important?

• Phospholipids create a barrier in water
• define outside vs. inside
• they make Cell Membrane

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Steroids

• Structure
• 4 fused C rings ??
• different steroids created by attaching different
  functional groups to rings
• different structure creates different function
• What are some examples

cholesterol
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Cholesterol

• Important cell component
• Part of the cell membrane
• Used to make other types of 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!