Macromolecules. You are what you eat! Chapter 5. AP Biology

Transcription

1 Macromolecules You are what you eat! Chapter 5 AP Biology

2 Organic Compounds Contain bonds between CARBON glycosidic bond AP Biology

3 Carbohydrates Structure / monomer u monosaccharide Function u energy u raw materials u energy storage glycosidic bond u structural compounds Examples u glucose, starch, cellulose, glycogen AP Biology

4 Sugars Most names for sugars end in -ose Classified by number of carbons u 6C = hexose (glucose) u 5C = pentose (ribose) u 3C = triose (glyceraldehyde) C 2 O C 2 O C O O O O O O O O C C O O O O AP Biology Glucose Ribose Glyceraldehyde

5 Numbered carbons 5' C C 6' O AP Biology 4' C C 3' C 2' C 1' energy stored in C-C bonds harvested in cellular respiration

6 Simple & complex sugars Monosaccharides u simple 1 monomer sugars u glucose Disaccharides u 2 monomers O C 2 O O O O Glucose O u sucrose Polysaccharides u large polymers u starch AP Biology

7 Building sugars Dehydration synthesis monosaccharides disaccharide glucose 2 O fructose sucrose (table sugar) AP Biology

8 Polysaccharides Polymers of sugars u costs little energy to build u easily reversible = release energy Function: u energy storage starch (plants) glycogen (animals) w in liver & muscles u structure cellulose (plants) chitin (arthropods & fungi) AP Biology

9 Linear vs. branched polysaccharides slow release starch (plant) energy storage What does branching do? glycogen (animal) AP Biology fast release Faster digestion!

10 Polysaccharide diversity Molecular structure determines function in starch in cellulose AP Biology u isomers of glucose u structure determines function

11 Cellulose Most abundant organic compound on Earth u herbivores have evolved a mechanism to digest cellulose u most carnivores have not: 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?!

12 elpful bacteria ow can herbivores digest cellulose so well? u BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Caprophage Ruminants Tell I me eat about the rabbits, again, WAT! George!

13 Proteins Structure u monomer = amino acids 20 different amino acids u polymer = polypeptide protein can be one or more polypeptide chains folded & bonded together large & complex molecules complex 3-D shape 2O hemoglobin Rubisco growth hormones

14 Proteins Most structurally & functionally diverse group Function: involved in almost everything u enzymes (pepsin, lactase, DNA polymerase) u structure (keratin, collagen) u carriers & transport (hemoglobin, aquaporin) u cell communication signals (insulin & other hormones) receptors u defense (antibodies) u movement (actin & myosin) u storage (bean seed proteins)

15 Amino acids Structure u central carbon u amino group u carboxyl group (acid) u R group (side chain) variable group different for each amino acid N confers unique chemical properties to each amino acid w like 20 different letters of an alphabet w can make many words (proteins) C R Oh, I get it! amino = N2 acid = COO O C O

16 Building proteins Peptide bonds u covalent bond between N 2 (amine) of one amino acid & COO (carboxyl) of another u C N bond dehydration synthesis 2O peptide bond

17 Building proteins Polypeptide chains have direction u N-terminus = N 2 end u C-terminus = COO end u repeated sequence (N-C-C) is the polypeptide backbone can only grow in one direction

18 Protein structure & function Function depends on structure u 3-D structure twisted, folded, coiled into unique shape pepsin hemoglobin collagen

19 Protein structure 1 amino acid sequence peptide bonds determined by DNA 2 R groups bonds R groups hydrophobic interactions disulfide bridges ( & ionic bonds) 3 multiple polypeptides hydrophobic interactions 4

20 Sulfur containing amino acids Cysteine, Methionine Form disulfide bridges u covalent cross links betweens sulfhydryls u stabilizes 3-D structure -S S- You wondered why perms smell like rotten eggs?

21 Protein denaturation Unfolding a protein u conditions that disrupt bonds, ionic bonds, disulfide bridges temperature p salinity u alter 2 & 3 structure thus, altering 3-D shape u destroys functionality In Biology, size doesn t matter, SAPE matters! some proteins can return to their functional shape after denaturation, many cannot

22 Nucleic Acids Function: u genetic material DNA stores information w genes w blueprint for building proteins n DNA RNA proteins transfers information w blueprint for new cells w blueprint for next generation proteins

23 Nucleic Acids Examples: u RNA (ribonucleic acid) single helix u DNA (deoxyribonucleic acid) double helix Structure: u monomers = nucleotides DNA RNA

24 Nucleotides 3 parts u nitrogen base (C-N ring) u pentose sugar (5C) ribose in RNA deoxyribose in DNA u phosphate (PO 4 ) group Nitrogen base I m the A,T,C,G or U part! Are nucleic acids charged molecules?

25 Lipids Lipids are composed of C,, O u long hydrocarbon chains (-C) Family groups u fats u phospholipids u steroids Do not form polymers u big molecules made of smaller subunits u not a continuing chain

26 Fats Structure: u glycerol (3C alcohol) + fatty acid fatty acid = long C tail with carboxyl (COO) group head enzyme 2 O dehydration synthesis

27 Fats store energy Long hydrocarbon chain u polar or non-polar? u hydrophilic or hydrophobic? Function: u energy storage concentrated w all -C! 2x carbohydrates u cushion organs u insulates body think whale blubber! Why do humans like fatty foods?

28 Saturated fats All C bonded to No C=C double bonds u long, straight chain u most animal fats u solid at room temp. contributes to cardiovascular disease (atherosclerosis) = plaque deposits

29 Unsaturated fats C=C double bonds in the fatty acids u plant & fish fats u vegetable oils u liquid at room temperature the kinks made by double bonded C prevent the molecules from packing tightly together mono-unsaturated? poly-unsaturated?

30 Phospholipids Structure: u glycerol + 2 fatty acids + PO 4 PO 4 = negatively charged (which means the head molecule is ) It s just like a penguin A head at one end & a tail at the other!

31 Phospholipids in water ydrophilic heads attracted to 2 O ydrophobic tails hide from 2 O u can self-assemble into bubbles bubble = micelle can also form a phospholipid bilayer early evolutionary stage of cell? water bilayer water

32 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

33 Cholesterol Important cell component u animal cell membranes u precursor of all other steroids including vertebrate sex hormones u high levels in blood may contribute to cardiovascular disease

34 From Cholesterol Sex ormones What a big difference a few atoms can make!