Macromolecules a.k.a. biomolecules What Mamma Never Told You!

I. Overview I A. Large molecules found in living matter B. Organic - featuring carbon as the key structural element of the molecule C. Assembled as polymers: large molecules built by linking many smaller molecules together, which act as subunits of the macromolecule 1. molecules that act as subunits are called monomers

D. Four distinct classes I. Overview (cont.) D. Four distinct classes 1. carbohydrates 2. lipids 3. proteins 4. nucleic acids

I. Overview (cont.) E. Synthesized by means of polymerization 1. condensation rxn: a rxn during which monomers are covalently linked, producing one H2O molecule per rxn - specifically call a dehydration rxn Requires Energy Catalyzed by an enzyme pg. 63

I. Overview (cont.) F. Broken down by means of Hydrolysis 1. a rxn in which covalent bonds between monomers are broken by the addition of a H2O molecule - the reverse of dehydration Catalyzed by an enzyme Requires Energy pg. 63

II. Carbohydrates A. Monomer: monosaccharides (simple sugars) B. Classified based on number of simple sugar molecules 1. monosaccharide - single sugar molecule a. primary energy source/nutrient for cells b. product of photosynthesis c. generally have the empirical formula of CH2O ex: glucose C6H12O6 2. disaccharide: two simple sugar molecules a. ex: maltose = glucose + glucose (sugar produced in beer fermentation) b. ex: lactose = glucose + galactose (sugar found in milk) c. ex: sucrose = glucose + fructose (table sugar)

disaccharide polymerization example Dehydration Video Link pg. 65 Dehydration Video Link

II. Carbohydrates (cont.) 3. polysaccharides - 300 to 1,000 simple sugars a. monosaccharide storage molecule b. structural molecule c. ex: starch and cellulose - which differ only in a slight structural configuration starch v. cellulose pg. 67 pg. 67

III. Lipids A. Technically not a polymer: bonding occurs between two different types of molecules B. Mostly hydrophobic with diverse functions 1. insoluble in H2O = dissolvable in non-polar solvents C. Fats: constructed from 1. glycerol: a three carbon alcohol 2. fatty acid: a carboxylic acid pg. 69

a. no double bonds between carbons in the fatty acid tail C. Examples 1. saturated fat a. no double bonds between carbons in the fatty acid tail b. usually solid at room temperature c. most animal fats 2. unsaturated fat a. one or more double bonds in the fatty acid tail b. the molecule “kinks” at each C=C 1. as a result the molecule cannot stack well enough to solidify at room temperature  usually liquid at room temperature 2. plant fats Pg. 69 Pg. 69

D. Energy Content 1. one gram of lipid/fat stores twice as much energy as a gram of carbohydrate. 2. lipids are more compact fuel reservoir than carbohydrates,  animals store more energy than plants which tend to store bulky starch molecules E. Phospholipids 1. major component of all biological membranes 2. glycerol + 2 fatty acids + a phosphate group on the third carbon of glycerol 3. one of the tails have one or more =‘s

4. The “head” is hydrophilic - the “tail” is hydrophobic  In aqueous solution the molecule will form a bilayer as the heads orient themselves towards the H2O leaving the tails to orient themselves away from the H2O Pg. 70

This is what happens when phospholipids and water mix Pg. 71 This is what happens when phospholipids and water mix

IV. Proteins A. The molecular tool/workhorse for most cellular functions B. Monomers: amino acids 1. chains of amino acids (a.a.) are called polypeptides - named for the peptide bond that forms when two a.a. covalently bond a. one or more polypeptides = protein 2. 20 different amino acids exist and they vary enormously in their chemistry due to side groups on the central portion of the molecule

Polypeptide Structure Condensation rxn Pg. 73

C. A protein’s function depends on its 3D shape, called its final, or functional, conformation D. 4 levels of protein structure 1. Primary - the unique sequence of a.a. 2. Secondary - regular, repeated coiling, or pleated sheeting, of a protein 3. Tertiary - irregular contortions due to bonding between side groups of the amino acids 4. Quaternary - structure that results from bond interactions between several polypeptides within the same protein E. Tertiary and quaternary structures are active conformations F. Proteins lose their activity by denaturing due to exposure to heat and/or chemicals, including changes in pH

Primary Structure Of A Protein Pg. 75 Primary Structure Of A Protein

Secondary Structure Of A Protein Pg. 76 Secondary Structure Of A Protein

Tertiary Structure Of A Protein Pg. 79

Quaternary Structure Of A Protein Pg. 78

Denaturing Of A Protein Pg. 79 Denaturing Of A Protein

V. Nucleic Acids A. DNA and RNA 1. Deoxyribonucleic Acid B. Monomers are nucleotides 1. Adenine 2. Guanine 3. Cytosine 4. Thymine 5. Uracil (RNA only - takes the place of thymine)

C. DNA 1. contains the code for the sequence, and synthesis of, mRNA a. mRNA codes for a.a. sequence in protein 2. genes and alleles located here 3. indirectly programs all cellular activity D. RNA 1. functions in the actual synthesis of proteins indirectly coded for by DNA a. recall transcription and translation 2.  genetic information moves thusly: DNA  RNA  Protein

The End