Five Sense Biochemistry

Love thy Lipids

Lipid Chemistry

Main Elements of Lipids: Carbon hydrogen & oxygen

The ratio of hydrogen to carbon is greater than 2:1

Lipid Chemistry

• Lipids are non-polar, hydrophobic molecules

• How do lipids behave in the presence of polar molecules such as water?

• Lipids include fats, phospholipids, waxes & steroids

Function of Fats

• Energy storage• Fats contain 9 calories/gram whereas

carbohydrates contain 4 calories/gram

Fats• Fats are composed of glycerol & three

fatty acids (tri-glyceride)

Saturated Fat

• Study the pattern of carbon & hydrogen bonding—why do you think this is a saturated fat?

Unsaturated Fat

• Study the pattern of carbon & hydrogen bonding—why do you think this is a unsaturated fat?

Unsaturated Fats: Structure & Function

How does the double bond affect the function of the molecule in cell membranes?

Trans Fats• Found in foods that contain

partially hydrogenated oils• Linked to increased heart

disease• Cause increased levels of “bad”

blood cholesterol and decreased levels of “good” cholesterol

• http://www.mayoclinic.com/health/trans-fat/CL00032• http://www.indiana.edu/~oso/Fat/SolidNLiquid.html

Trans Fats

• What makes trans fats different than other unsaturated fats?

• How will this structure affect the molecule’s ability to bend?

Trans Fats & the Cell Membrane

• Trans fats get stored in the cell membrane• As much as 20% of the cell membrane

can consist of these unnatural fats• Trans fats don’t kink—how will this affect

the function of the cell membrane?

Phospholipids• Similar to a fat, but contains only two fatty

acids and a phosphate group.• Polar heads & non-polar tails• Where are phospholipids found in cells?

Steroids (Sterols)• Lipids with four fused rings & no fatty acids• Cholesterol is found in cell membranes &

plays a role in hormone synthesis