Essential knowledge 4.A.1: The subcomponents of biological molecules and their sequence determine the properties of that molecule.

Macromolecules Bozeman Biology: https://www.youtube.com/watch?v=PYH63o10iTE&list=PL8GOEDwLwlIOiSrWJuCzUxJ_zMemyYDDZ&index=5 Other macromolecule video: https://www.youtube.com/watch?v=H8WJ2KENlK0&list=PL8GOEDwLwlIOiSrWJuCzUxJ_zMemyYDDZ

Structure and function of polymers are derived from the way their monomers are assembled.

Polymers Covalent monomers Condensation reaction (dehydration reaction): One monomer provides a hydroxyl group while the other provides a hydrogen to form a water molecule Hydrolysis: bonds between monomers are broken by adding water (digestion)

Carbohydrates Monosaccharides CH2O formula; √ multiple hydroxyl (-OH) groups and 1 carbonyl (C=O) group: aldehyde (aldoses) sugar ketone sugar √ cellular respiration; √ raw material for amino acids and fatty acids

Carbohydrates Disaccharides glycosidic linkage (covalent bond) between 2 monosaccharides; covalent bond by dehydration reaction Sucrose (table sugar) most common disaccharide

Carbohydrates Polysaccharides Energy Storage: Polysaccharides Structural in function: Plants: Cellulose Animals:Chitin (found in the exoskeleton of arthropods; also in the cell walls of fungi; Polysaccharides Energy Storage: Plants: starch (glucose monomers) Animals: glycogen

Carbohydrates Summary: Carbohydrates are composed of sugar monomers whose structures and bonding with each other by dehydration synthesis determine the properties and functions of the molecules. Illustrative examples include: cellulose versus starch.

Lipids No polymers; glycerol and fatty acid Fats, phospholipids, steroids Hydrophobic; H bonds in water exclude fats Carboxyl group = fatty acid Non-polar C-H bonds in fatty acid ‘tails’ Ester linkage: 3 fatty acids to 1 glycerol (dehydration formation) Triacyglycerol (triglyceride) Saturated vs. unsaturated fats; single vs. double bonds

Phospholipids 2 fatty acids instead of 3 (phosphate group) ‘Tails’ hydrophobic; ‘heads’ hydrophilic Micelle (phospholipid droplet in water) Bilayer (double layer); cell membranes

Steroids Lipids with 4 fused carbon rings Ex: cholesterol: cell membranes; precursor for other steroids (sex hormones); atherosclerosis

Lipids Summary In general, lipids are nonpolar; however, phospholipids exhibit structural properties, with polar regions that interact with other polar molecules such as water, and with nonpolar regions where differences in saturation determine the structure and function of lipids.

Proteins Importance: instrumental in nearly everything organisms do; 50% dry weight of cells; most structurally sophisticated molecules known Monomer: amino acids (there are 20) ~ carboxyl (-COOH) group, amino group (NH2), H atom, variable group (R)…. Variable group characteristics: polar (hydrophilic), nonpolar (hydrophobic), acid or base Three-dimensional shape (conformation) Polypeptides (dehydration reaction): peptide bonds~ covalent bond; carboxyl group to amino group (polar)

Protein Structure Primary Secondary Tertiary Quaternary

Primary Structure Conformation: Linear structure Molecular Biology: each type of protein has a unique primary structure of amino acids Ex: lysozyme Amino acid substitution: hemoglobin; sickle-cell anemia

Secondary Structure Conformation: coils & folds (hydrogen bonds) Alpha Helix: coiling; keratin Pleated Sheet: parallel; silk

Tertiary Structure Conformation: irregular contortions from R group bonding √hydrophobic √disulfide bridges √hydrogen bonds √ionic bonds

Quaternary Structure Conformation: 2 or more polypeptide chains aggregated into 1 macromolecule Ex: collagen (connective tissue) hemoglobin

Types of Proteins Structural Protein Storage Proteins Transport Proteins Receptor Proteins Contractile Defensive Enzymes Signal Sensory Gene Regulator

Protein Summary In proteins, the specific order of amino acids in a polypeptide (primary structure) interacts with the environment to determine the overall shape of the protein, which also involves secondary tertiary and quaternary structure and, thus, its function. The R group of an amino acid can be categorized by chemical properties (hydrophobic, hydrophilic and ionic), and the interactions of these R groups determine structure and function of that region of the protein.

Nucleic Acids, I Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA) DNA->RNA->protein Polymers of nucleotides (polynucleotide): nitrogenous base pentose sugar phosphate group Nitrogenous bases: pyrimidines~cytosine, thymine, uracil purines~adenine, guanine

Nucleic Acids Pentoses: √ribose (RNA) √deoxyribose (DNA) √nucleoside (base + sugar) Polynucleotide: √phosphodiester linkages (covalent); phosphate + sugar

Nucleic Acids Inheritance based on DNA replication Double helix (Watson & Crick - 1953) H bonds~ between paired bases van der Waals~ between stacked bases A to T; C to G pairing Complementary

Nucleic Acids Summary In nucleic acids, biological information is encoded in sequences of nucleotide monomers. Each nucleotide has structural components: a five-carbon sugar (deoxyribose or ribose), a phosphate and a nitrogen base (adenine, thymine, guanine, cytosine or uracil). DNA and RNA differ in function and differ slightly in structure, and these structural differences account for the differing functions.

Directionality influences structure and function of the polymer. Examples are found in DNA, Proteins and Carbohydrates on the following slides.

DNA 1. Nucleic acids have ends, defined by the 3' and 5' carbons of the sugar in the nucleotide, that determine the direction in which complementary nucleotides are added during DNA synthesis and the direction in which transcription occurs (from 5' to 3'). http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120076/bio23.swf::How%20Nucleotides%20are%20Added%20in%20DNA%20Replication

Proteins 2. Proteins have an amino (NH2) end and a carboxyl (COOH) end, and consist of a linear sequence of amino acids connected by the formation of peptide bonds by dehydration synthesis between the amino and carboxyl groups of adjacent monomers.

Carbohydrates 3. The nature of the bonding between carbohydrate subunits determines their relative orientation in the carbohydrate, which then determines the secondary structure of the carbohydrate.