Bios 208 1st Edition Lecture 8 Outline of Last Lecture I. Urea Structure and Stanley Miller’s ExperimentII. Carbon Based CompoundsIII. Hydrocarbon StructuresIV. Isomers: Structural and GeometricV. Stereo IsomersVI. Functional GroupsVII. HydroxylVIII. CarbonylIX. CarboxylOutline of Current Lecture I. AminoII. SulfhydrylIII. PhosphateIV. Phosphate group significanceV. MethylVI. Biological PolymersVII. CarbohydratesCurrent LectureI. AminoA. Amines.B. Acts as a base; can pick up an H+ from the surrounding solution (water, in living organisms).C. Found in cells in the ionized form with a charge of 1+.II. SulfhydrylA. Thiols.B. Two sulfhydryl groups can react, forming a covalent bond. This “cross-linking” helps stabilize protein structure.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.C. Cross-linking of cysteines in hair proteins maintains the curliness or straightness of hair. Straight hair can be “permanently” curled by shaping it around curlers and then breaking and re-forming the cross-linking bonds.III. PhosphateA. Organic phosphates.B. Contributes negative charge to the molecule of which it is a part (2– when at the end of amolecule, as at left; 1– when located internally in a chain of phosphates).C. Molecules containing phosphate groups have the potential to react with water, releasingenergy.IV. Phosphate group significanceA. ATP is an important source of energy for cellular processes. One phosphate containing molecule, adenosine triphosphate (ATP), is the primary energy transferring molecule in the cell.B. ATP consists of an organic molecule called adenosine attached to a string of three phosphate groups.V. MethylA. Methylated compounds.B. Addition of a methyl group to DNA, or to molecules bound to DNA, affects the expression of genes.C. Arrangement of methyl groups in male and female sex hormones affects their shape andfunction.VI. Biological PolymersA. Large and complex: carbohydrates, proteins and nucleic acids (lipids are large but are notpolymers).B. Assembled from small and simple monomers called subunits. They exhibit emergent properties.C. There are about 50 common biological monomers, some of which have functions of their own.D. General functions:a) Storage.b) Structure, e.g. a spider’s web is made of proteins.c) Information.E. Monomers are joined to form polymers by a process called dehydration synthesis or condensation.F. One H2O is released for each bond formed.a) Energy is required.G. Polymers are broken down by hydrolysis. One H2O is consumed for each bond broken.b) Energy is released.VII. CarbohydratesA. General functions and properties.B. Monosaccharides have the formula (CH2O).c) n = 3 triose C3H6O3.d) n = 5 pentose C5H10O5.e) n = 6 hexose C6H12O6.C. Functions: energy storage (starch).D. Structure (cellulose, chitin).E. Information (cell surface receptors).F. Monosaccharides.a) Aldoses have a terminal carbonyl group (-C=O) and ketoses have an internal carbonyl group.b) Hydroxyl groups (-OH) are on the other carbons.c) Glucose and fructose are structural isomers.d) Glucose and galactose are enantiomers.H. Monosaccharides can have a linear form or a ring form. Both forms occur in water; inter-conversion does not require energy. Carbons are
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