General Botany (BIO 241), 2 Feb 2015 Review and Finish Ch. 2 topics: Review Carbohydrates and Lipids - energy-storage and structural functions - Starches and Cellulose Organic Molecules: Proteins, Nucleic Acids Secondary Metabolites DNA, Genes, and Genomes (order by descent)

Carbohydrates Monomers = simple sugars, monosaccharides -C, H, and O in 1:2:1 ratio (eg. C 6 H 12 O 6 ) - (CH 2 O) n, n= 3-7 (5, 6 most common) -C-skeleton with -OH (hydroxyl) groups 1 –C=O (carbonyl) group Hydrophilic or Hydrophobic? Yes: Hydrophilic

Monosaccharides Chain and Ring forms ~ -In solution, monosaccharides exist mainly in ring form (99%) -reaction between the –(C=O)H group (C1) and the hydroxyl (-OH) at C4 or C5 -Carbonyl group  hydroxyl -Equilibrium of 2 isomers, A and B, depending on orientation of OH relative to C6

Disaccharides Dehydration synthesis reaction between monosaccharides. ) - requires E input of 5.5. kcal/mole) Sucrose is the primary form in Which sugars are transported in plants (phloem sap).

Polysaccharides: polymers of monosaccharides Formed by dehydration synthesis reactions (occurs in amyloplasts) Energy Storage – must be hydrolyzed before being transported or used as energy source (input to respiration) Plants: -Starches - Alpha glucose subunits Amylose - unbranched Amylopectin - branched -Fructans (wheat, rye, barley) – fructose subunits Animals, fungi, prokaryotes: - glycogen (alpha glucose subunits)

Structural Polysaccharide – Cellulose (Beta-glucose subunits)

Triglycerides: glycerol with fatty acid sidechains Fats and oils: triglycerides that store energy

Phospholipids: structural lipids Self-assemble as a bilayer membrane in “solution”

Chemical characteristics: 4 interconnected hydrocarbon rings (= steroid) sterols = steroids with hydroxyl group on C-3 various side-chains (hydrocarbons, hydroxyls, hydroxyl groups) Functions: Structural (part of membranes) Hormones (signaling molecules) Lipids: steroids and sterols

Proteins Amino acid (protein subunit) - amino group (NH 2 ) - carboxyl group (COOH) - R-group (variable) Peptide bond = Linkage N of amino group and C of carboxyl group by Dehydration Rxn. Primary structure: sequence of amino acids. Directly encoded in DNA

Protein Secondary Structure: interactions among amino acids - hydrogen bonding - R-groups point outward (in helix) or Up/Down (pleated sheet), giving the protein its solubility and reactivity characteristics. Alpha Helix

Amino acid R-groups and protein placement R-group polarity in regions of protein 2° structure determines placement of peripheral and transmembrane proteins. Hydrophobic Amino Acids

Fluid Mosaic Model

Nucleic Acids -composed of nucleotides Nucleotide parts: - nitrogenous base adenine cytosine guanine thymine uracil - sugar ribose (5-C) deoxyribose (6-C) - phosphate DNA= deoxyribose, ACTG RNA= ribose, ACUG

DNA: Double stranded; each strand is the reverse complement of the other. Hydrogen bonding between nucleotide pairs: A T/UC G Nucleotides are linked into amino acids by dehydration synthesis.

ATP – adenosine (a nucleotide) triphosphate Function: Cellular Energy Currency