User:Sarah Burkhard/Notebook/471 Nano Notebook/2017/02/07

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Seminar on drug resistance anti- Tubercolosis resistance since 1940s known that anti-biotic resistance is increasing TB: 4700 people die everyday bacillus causing disease: Mycobacterium tuberculosis benzene rings make drug molecules flat and easier to diffuse to local need spreading into rural areas almost all strains of staph bacterium are resistant to penicillin introduced by Alexander Fleming structure determined by X ray crystallography has an amide beta lactam ( 4 member ring ) monobactams: showed second ring not needed penicillin is blocking the enzyme for transpeptimerization cell wall gets weaker-- bacterium dies resistance to penicillin comes from production of beta-lactamase ( hydrolyzing proteins ) antibacterial resistance increased in 1980s bacteria have another way to transpeptimerize Today's objective Measure UV absorbance of 0.5 mM HAuCl4 at different pH values Procedure 1) calibrate pH meter with buffers 4, 7 , 10 2) refill pH electrode solution prepare 0.5 mM HAuCl4 solutions, pH 4 to pH 14 use quartz cuvette and measure absorbance 800 nm to 290 nm the relevant wavelength at which gold chloride absorbs is around 310 nm the final volume of all solutions should be 3 ml to get to pH 4 we will add: 300 uL of 5 mM HAuCL, 240 uL of 5 mM NaOH, 2460 uL of neutralized water to get to pH 5 we will add 300 uL of 5 mM HAuCl, 1470 uL of 1 mM NaOH, 1170 uL of neutralized water to get to pH 6 we will add 300 uL of 5 mM HAuCL, 1497 uL of 1 mM NaOH, 1197 uL of neutralized water to get to pH 7 we will add 300 uL of 5 mM HAuCl, 300 uL 5 mM NaOH, 2400 uL of neutralized water to get pH 8 we will add 300 uL of 5 mM HAuCl, 300 uL 5 mM NaOH, 3 uL 1 mM NaOH, 2397 uL of neutralized water Notes buffer bc CO2 is in equilibrium with the solution ( NaHCO) H2CO3 --> Na2CO3 , NaHCO3 ) our 5 mM will likely not be 5 mM . Should measure pH of solution and use effective concentration to make calculations. expected pH 1 mM base: 11 . actual: 10.28 expected pH 5 mM: 11.7 . actual: 11.4 expected pH 1 M : 14. actual: 13.33 expected pH 5 mM acid: 2.3 actual: 2.32