Lipids

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Lipids
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Lipids

• Lipids are a loosely defined based on solubility
  rather than structure.
• Dissolve in non-polar solvents.
• Hydrophobic do not dissolve in water.
• 5 types
• Triglycerides
• phospholipids
• Glycolipids
• Steroids
• waxes

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Fatty Acids

• Seventy different fatty acids
• Usually have an even number of carbons
• Differ in length of the carbon chain.
• May contain double covalent bonds.
• Carboxyl group (-COOH) at one end
• Hydrogen occupies most of the other binding sites.

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Triglyceride fats and oils

• One glycerol molecule and three fatty acids.
• Fat lipid that is solid at room temp
• Oil lipid that is liquid at room temp
• Concentrated source of energy
• More than twice as much per gram as
  carbohydrates.
• On average, fats yield about 9 kcal of chemical
  energy per gram, as compared with 4 kcal per gram
  for carbohydrates.

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Triglycerides

• Saturated fats
• No double covalent bonds - have the most
  hydrogen possible.
• Animal fats - butter
• Unsaturated
• Have double covalent bonds between two adjacent
  carbons fewer hydrogen than saturated fats
• Olive oil, peanut oil, corn oil, more common in
  plants than animals
• Polyunsaturated
• More than one double covalent bond

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Hydrogenated oil

• Artificially add hydrogen to eliminate double
  bonds.
• Also eliminates the health advantage.

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Phospholipids

• Phospholipids form biological membranes.
• Made of three subunits
• Glycerol
• Fatty Acids one saturated the other
  unsaturated.
• Phosphate Group (in place of one of the fatty
  acids)
• Contain polar head - hydrophilic
• Non-polar tails hydrophobic
• Cell membrane is made up of two layers of
  phospholipids

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Sterols

• No fatty acids
• Rigid backbone of four fused-together carbon
  rings
• Differ in number, type, and position of
  functional group.
• Cholesterol - most important and most common
  type in animals
• Plants dont have cholesterol that is why
  vegetable oil is cholesterol free

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Sterols

• Cholesterol gets remodeled
• Steroids - including testosterone and estrogen
• Vitamin D -
• Bile salts -

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Terpenes

• Long chain lipid
• Component of biological pigments
• Chlorophyll
• Retinal

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Waxes

• Long-chain fatty acids tightly packed and linked
  to long chain alcohols or carbon rings
• Similar to triglyceride, but instead of glycerol
  there is a long chain alcohol.
• Firm consistency, repel water
• Found in the cuticle covering in plants, insects,
  fruit skins, and petals (good for conserving
  water)

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Prostaglandins

• Modified fatty acids with 2 non-polar tails
  attached to a 5 carbon ring
• Local chemical messengers in vertebrate tissue.

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Artherosclerosis

• Deposits of fatty tissue (plaque) to the lining
  of the blood vessel
• blocking blood flow.