Lipids

1
Lipids

• No polymers
• Function
• energy source - 9.3 cal/g
• biological membranes
• steroid hormones
• waterproof covering
• Source
• diet or from other macromolecules

2

• Chemistry
• mostly C and H, with little O
• primarily covalent bonds
• hydrophobic
• 3 Classes
• fats, oils, waxes
• phospholipids
• steroids

3

• Fats
• glycerol and fatty acids
• glycerol 3-C skeleton with OH attached to each C
• fatty acid carboxyl group attached to long
  carbon skeleton (16 to 18 carbons)

4

• Triacylglycerol (triglyceride)

5

• 3 Fatty Acids
• same or different saturated - straight
  chain
• variable length unsaturated - kink in chain

6

• Saturated fats
• animal fats
• solid at room temperature
• may contribute to cardiovascular disease
• Unsaturated fats
• plant and fish fats (oils)
• liquid are room temperature.
• kinks prevent tight packing of molecules

7

• Energy Storage
• more energy than polysaccharides
• long-term reserves in adipose cells
• Cushion vital organs
• Insulation
• whales, seals, and most other marine mammals
• Essential Fatty Acids
• Waxes

8

• Phospholipids
• glycerol 2 fatty acids phosphate group
• negative charge
• additional groups
  on
  3rd carbon

9

• Amphipathic
• hydrophilic phosphorus group
• hydrophobic fatty acid
• Structures
• Micelle

10

• Bilayer
• Major component
  of membranes

11

• Steroids
• four fused carbon rings
• varying functional groups

12

• Cholesterol
• animal cell membranes.
• precursor for all other steroids
• synthesized or in diet
• high levels of cholesterol in the blood may
  contribute to cardiovascular disease

13

• Lipoproteins
• carry cholesterol in blood
• dissolve lipid (oil) in blood (water)
• lipid-protein complex
• LDL bad cholesterol
• cholesterol from liver to tissues
• more lipid, less protein
• HDL good cholesterol
• cholesterol to liver for excretion
• more protein, less lipid