CH 5 Macromolecules Building Blocks of Life AP
CH. 5 Macromolecules Building Blocks of Life AP Biology 2007 -2008
Macromolecules § Smaller organic molecules join together to form larger molecules u macromolecules § 4 major classes of macromolecules: carbohydrates u lipids u proteins u nucleic acids u AP Biology
Polymers § Long molecules built by linking repeating building blocks in a chain u monomers § building blocks § repeated small units u H 2 O covalent bonds HO H Dehydration synthesis AP Biology HO H
How to build a polymer § Synthesis u You gotta be open to “bonding! joins monomers by “taking” H 2 O out § one monomer donates OH– § other monomer donates H+ § together these form H 2 O u H 2 O requires energy & enzymes HO H Dehydration synthesis HO H enzyme Condensation reaction AP Biology HO H
How to break down a polymer Breaking up is hard to do! § Digestion u use H 2 O to breakdown polymers § reverse of dehydration synthesis § cleave off one monomer at a time § H 2 O is split into H+ and OH– w H+ & OH– attach to ends requires enzymes HO u releases energy H 2 O u enzyme H Hydrolysis AP Biology Digestion HO H
Carbohydrates § Carbohydrates are composed of C, H, O carbo - hydr - ate CH 2 O (CH 22 O) O)xx C 66 H 12 O (CH 12 66 § Function: energy u raw materials u energy storage u structural u § Monomer: sugars § ex: sugars, starches, cellulose sugar sugar AP Biology sugar
Sugars § Most names for sugars end in -ose § Classified by number of carbons 6 C = hexose (glucose) u 5 C = pentose (ribose) u 3 C = triose (glyceraldehyde) u CH 2 OH H HO O H OH H AP Biology 6 H OH Glucose H CH 2 OH OH C O H HO H 5 OH O HO H Ribose H H C OH 3 OH H Glyceraldehyde
Functional groups determine function carbonyl aldehyde carbonyl ketone AP Biology
Sugar structure 5 C & 6 C sugars form rings in solution Where do you find solutions in biology? In cells! AP Biology Carbons are numbered
Numbered carbons C 6' 5' C O C 4' C 1' energy stored in C-C bonds C 3' AP Biology C 2'
Simple & complex sugars § Monosaccharides simple 1 monomer sugars u glucose u § Disaccharides 2 monomers u sucrose u § Polysaccharides large polymers u starch u AP Biology CH 2 OH H HO O H OH H H OH Glucose H OH
Building sugars § Dehydration synthesis monosaccharides disaccharide H 2 O | sucrose (table sugar) | glucose AP Biology | fructose
Polysaccharides § Polymers of sugars costs little energy to build u easily reversible = release energy u § Function: u energy storage § starch (plants) § glycogen (animals) w in liver & muscles u structure § cellulose (plants) § chitin (arthropods & fungi) AP Biology
Linear vs. branched polysaccharides slow release starch (plant) energy storage What does branching do? glycogen (animal) AP Biology fast release Let’s go to the videotape!
Polysaccharide diversity § Molecular structure determines function in starch in cellulose isomers of glucose u structure determines function… u AP Biology
Digesting starch vs. cellulose starch easy to digest enzyme cellulose hard to digest enzyme AP Biology
Cellulose § Most abundant organic compound on Earth herbivores have evolved a mechanism to digest cellulose u most carnivores have not u § that’s why they eat meat to get their energy & nutrients § cellulose = undigestible roughage AP Biology But it tastes like hay! Who can live on this stuff? !
Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet Regents Biology
Helpful bacteria § How can herbivores digest cellulose so well? u BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Ruminants Regents Biology Tell Ime about eat the rabbits, WHAT! again, George!
Lipids long term energy storage concentrated energy AP Biology 2006 -2007
Lipids § Lipids are composed of C, H, O u long hydrocarbon chains (H-C) § “Family groups” fats u phospholipids u steroids u § Do not form polymers big molecules made of smaller subunits u not a continuing chain u AP Biology
Fats § Structure: u glycerol (3 C alcohol) + fatty acid § fatty acid = long HC “tail” with carboxyl (COOH) group “head” enzyme H 2 O dehydration synthesis AP Biology
Building Fats § Triacylglycerol 3 fatty acids linked to glycerol u ester linkage = between OH & COOH u hydroxyl AP Biology carboxyl
Dehydration synthesis H 2 O dehydration synthesis enzyme H 2 O AP Biology enzyme HO
Fats store energy § Long HC chain Why do humans like fatty foods? polar or non-polar? u hydrophilic or hydrophobic? u § Function: u energy storage § concentrated w all H-C! § 2 x carbohydrates cushion organs u insulates body u AP Biology § think whale blubber!
Saturated fats § All C bonded to H § No C=C double bonds long, straight chain u most animal fats u solid at room temp. u § contributes to cardiovascular disease (atherosclerosis) = plaque deposits AP Biology
Unsaturated fats § C=C double bonds in the fatty acids plant & fish fats u vegetable oils u liquid at room temperature u § the kinks made by double bonded C prevent the molecules from packing tightly together AP Biology mono-unsaturated? poly-unsaturated?
Phospholipids § Structure: u glycerol + 2 fatty acids + PO 4 § PO 4 = negatively charged AP Biology
Phospholipids § Hydrophobic or hydrophilic? fatty acid tails = hydrophobic u PO 4 head = hydrophillic “attracted to water” u split “personality” u Come here, No, go away! interaction with H 2 O is complex & very important! AP Biology “repelled by water”
Phospholipids in water § Hydrophilic heads “attracted” to H 2 O § Hydrophobic tails “hide” from H 2 O u can self-assemble into “bubbles” § bubble = “micelle” § can also form a phospholipid bilayer § early evolutionary stage of cell? water bilayer AP Biology water
Why is this important? § Phospholipids create a barrier in water define outside vs. inside u they make cell membranes! u Tell them about soap! AP Biology
Steroids § Structure: u 4 fused C rings + ? ? § different steroids created by attaching different functional groups to rings § different structure creates different function u examples: cholesterol, sex hormones cholesterol AP Biology
Cholesterol § Important cell component animal cell membranes u precursor of all other steroids u § including vertebrate sex hormones u AP Biology high levels in blood may contribute to cardiovascular disease
Cholesterol Important component of cell membrane AP Biology helps keep cell membranes fluid & flexible
From Cholesterol Sex Hormones § What a big difference a few atoms can make! AP Biology
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