Biochemical Molecules of Plants

- Biological molecules


I.             Types of biological molecules
                A.            Inorganic - cofactors, catalysts, equilibria, etc., many participate as part of or with organic molecules
                B.            Organic - carbohydrates, lipids, proteins, nucleic acids, porphyrins, and secondary plant products
II             Classification, structure, and function of major biological molecules
                A.            Carbohydrates
                                1.             Sugars and related compounds - ENERGY
                                                a)            Glucose & fructose
                                                                1)            Hexoses of central importance in cell metabolism
                                                b)            Sucrose - a disaccharide composed of glucose and fructose - major translocated carbohydrate in plants
                                                c)             Polysaccharides
                                                                1)            Starch - branched polymer of glucose
                                                                                a)            Amylose - linear polymer (α-1,4)
                                                                                b)            Amylopectin - branched polymer (α-1,6)
                                                                                c)             Easily hydrolyzed to glucose
                                                                                d)            Major storage carbohydrate
                                                                2)            Cellulose - linear polymer of glucose
                                                                                a)            Glucose units connected differently (β-1,4)
                                                                                b)            Difficult to hydrolyze
                                                                                c)             Structural carbohydrate (along with hemicellulose, {xylose, arabinose}, lignin {coniferyl, coumaryl, synapyl alcohols}, and pectin {galactose})
                B.            Lipids
                                1.             Glycerol and related compounds - FAT STORAGE, COATING, & MEMBRANES
                                                a)            Triglycerides (fat) - linoleic and linolenic acid
                                                b)            Coating (wax, cutin) - ester (RCOOR) of above with 20 - 28 carbons
                                                c)             Membranes (phospholipids) - fatty acid replaced by phosphate (hydrophilic & hydrophobic) membrane fluidity
                C.            Proteins
                                1.             Enzymes - CATALYZE REACTIONS; METABOLISM
                                                a)            Amino acids - from translation of RNA
                                                a)            Peptide bonds
                D.            Nucleic acids - GENETIC INFORMATION
                                1.             DNA:  Adenine, guanine (purines), thymine, & cytosine (pyrimidines)
                                2.             RNA:  Adenine, guanine (purines), uracil, & cytosine (pyrimidines)
                E.            Phorphyrins
                                1.             Chlorophyll - PHOTOSYNTHESIS
                                                a)            absorb photons
                                                b)            transfer electron to acceptor - then protolysis to replace it
                F.            Secondary products
                                1.             Phenolics  (anthocyanins, tannins) - PIGMENTATION, RESISTANCE
                                2.             Steroids & terpenoids - SCENTS, RESISTANCE, (used by man for RUBBER)

                                3.             Alkaloids - RESISTANCE (used by man for DRUGS such as CAFFEINE, COCAINE, MORPHINE, etc.)

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