Vocab review• Monomer= generic name for a building block unit

– eg: a monosaccharide is a monomer of a polysaccharide

• Polymer= generic name for 3 or more monomers bonded together– eg= three or more monosaccharides bonded

together are a polymer, specifically a polysaccharide

• Dehydration synthesis= building bigger molecules by taking water out

• Degradation hydrolysis= breaking up big molecules into smaller ones by putting water in

Lipidslong term energy storage

concentrated energy

Lipids • Lipids are composed of C, H, O

– Defining characteristic: long hydrocarbon chains (H-C) or rings

• 3 Classes:– fats– phospholipids– steroids

• Do not form polymers– big molecules made of smaller subunits– not a continuing chain

Fats (triglycerides and fatty acids) • Structure:

– glycerol– 3 fatty acids

dehydration synthesis

H2O

enzyme

Fats have functions!

• Long HC chain– polar or non-polar?– hydrophilic or hydrophobic?

• Function:– energy storage – cushion organs– insulates body

• think whale blubber!

Saturated fats

• All C bonded to H

• No C=C double bonds– long, straight chain– most animal fats – solid at room temp.

Unsaturated fats

• C=C double bonds in the fatty acids– plant & fish fats – vegetable oils– liquid at room temperature

• the kinks made by doublebonded C prevent the molecules from packing tightly together

Saturated vs. unsaturated

Phospholipids • Structure:

– glycerol + 2 fatty acids + PO43-

Phospholipids

– fatty acid tails =

– PO43- head =

– split “personality”

hydrophobichydrophilic

Phospholipids in water

• Hydrophilic heads “attract” to H2O

• Hydrophobic tails “hide” from H2O

– can self-assemble into “bubbles” or bilayers

bilayer

water

water

Why is this important?• Phospholipids create a barrier in water

– define outside vs. inside– they make cell membranes!

Steroids• Structure:

– 4 fused C rings + functional groups + HC tail• different steroids created by attaching different

functional groups to rings• different structure creates different function

cholesterol

Cholesterol• Important cell component

– animal cell membranes– precursor of all other steroids

• including vertebrate sex hormones

Cholesterol

helps keep cell membranes

fluid & flexible

Important component of cell membrane

FAT

STEROID

PHOSPHOLIPID

Nucleic acids

• Monomers= nucleotides

• Polymers= nucleic acids (DNA, RNA, ATP)

nucleotide