section 5 handout_answers

section 5 handout_answers - Bio1A Spring 2011 Discussion...

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Bio1A Spring 2011 Discussion Section Handout #5 Week of February 28, 2011 Terms to Know Doubling Time Lytic/T4 Restriction endonuclease Log Phase Lysogenic/Lambda Mutant frequency Exponential Phase Mutation Rate=# change/bp/gen Wild type Stationary Phase Transformation Polymerase Plasmid Conjugation Ligase Replication Fork Transduction Meselson Stahl Experiment Bacteriophage Transposons Origin of Replication Felix d’Herelle Pilus Sequential fractionation Labile junction Palindrome sequence Arthur Kornberg Leading Strand Lagging Strand A Protein Helicase DNA primase MRSA/ MDR TB 1) How many free protons can be found in a bacterium with a diameter of 1μm and pH 7? Assume the bacterium is spherical. R = 0.5(1x10 -6 m) = 5x10 -7 m V = (4/3)πr 3 = 5.236x10 -19 m 3 = 5.236x10 -16 L (1m 3 = 1000L) 5.236x10 -16 L * 1x10 -7 mol H+/L = 5.236x10 -23 mol H+ 5.236x10 -23 mol H+ * 6.02x10 23 molecules/mol = 31.5 H+ 30% reduction due to cell wall = 22 free protons 2) Under ideal conditions, the gram negative bacteria Escherichia coli replicates every 20 minutes. The average mass of an E. coli bacterium is approximately 2*10^-19 grams. If one bacterium is given an infinite supply of nutrients, what will be the mass of the colony it gives rise to in 24 hours? In 48 hours? In what phase of growth do bacteria spend most of their time? 24 hours -> 2 72 * 2*10 -19 = (2 2 ) * (2 10 ) 7 * 2*10 -19 = 8*10 2 g, a little less than 1 kg. (a full nalgene bottle) 48 hours -> 2 144 * 2*10 -19 = (2 4 ) * (2 10 ) 14 * 2*10 -19 = 3*10 24 g or about 0.1% the mass of the Earth.
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This note was uploaded on 09/20/2011 for the course CHEMISTRY 120 taught by Professor Head-gordon during the Spring '11 term at ASU.

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section 5 handout_answers - Bio1A Spring 2011 Discussion...

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