FINAL QUIZ QUESTION n As a class, we have claimed that there is starch in potatoes. With your table partners, prove to me that this is true. Petri dishes and potatoes will be given to you. The rest is up to you. Explain the process you used and show me your results.

LIPIDS n Made of Carbon, Hydrogen, and Oxygen n Are Hydrophobic n 4 Classes –Waxes –Steroids –Phospholipids –Fats (Triglycerides)

Waxes n Some act as waterproofing systems –Example- leaves and feathers n Other waxes –Beeswax, earwax

Steroids n Skeleton of interconnected rings of carbon n Examples –Cholesterol- in cell membranes –Sex Hormones (testosterone, estrogen, etc.) –Chlorophyll in plants –Retinol in our eyes

Cholesterol- A steroid

Phospholipids n Similar to fats but only 2 hydrocarbon chains n Head is composed partly of PHOSPHATE Group (PO 4 ) n very important in cell membrane

Phospholipid Head - glycerol + phosphate 2 Fatty Acid tails

Fats (aka Triglycerides) n Made of Glycerol + 3 Fatty acids n Large hydrocarbon chains (H + C)

Triglyceride ( fat)

How does a triglyceride differ from a carbohydrate? n Store much more energy (more than 2x) n Much more difficult to break down

Types of fats n Saturated n Unsaturated –Monounsaturated –Polyunsaturated

A Saturated Fat

Saturated Fats n Carbons bonded to max. # of hydrogens –No double bonds n Solids at room temperature n Bacon, grease, lard, butter, cheese, chocolate

Unsaturated Fats n Carbons not bonded to max # of hydrogens –Some carbons double bonded- chain becomes kinked (see drawing) n Liquid at room temp. (OILS) n Vegetable oil, olive oil, peanut oil, fish oil, etc.