Lecture 14 - Lecture 14 Bacterial Growth Physical and...

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1 Lecture 14 Physical and Chemical Factors Affecting Growth BBOM 12e Sec. 6.1, 6.5-6.7 , 6.12-6.14 Temperature Bacterial Growth Quiz #2 Lectures 7-12; SGD-I Bacterial Growth Model Binary Fission Model 1 cell 2 cells Problem: Calculate Doubling Time (dt) Growth Rate (r) Growth rate (a.k.a Division rate) r = 1/dt (doublings per hour) n = Number of doublings (generations) in time, T Doubling time ( a.k.a. Generation time) dt = T/n How do we measure n?
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2 Bacterial Population Growth Curve BBOM 12e Fig. 6.10 Bacterial Population Growth Parameters Binary Fission Model 1 cell 2 cells Semilogarithmic graph EXPONENTIAL PHASE N O N Measure this key parameter: n =number of doublings in time, T log N - log N O log 2 = n n = 7 - 6 0.301 = 3.3 doublings in ~2.6 hours T =2.6 h Doubling time dt = T/n = 2.6/3.3 = ~ 0.8 h During exponential growth phase: Growth rate (=Division rate) r = 1/dt = 1.27 doublings/h (= 47-48 min) BBOM 12e Sec. 6.1, 6.5-6.7
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3 The Top Five Environmental Factors Affecting Growth Temperature Low and high pH Salinity (Water activity) O 2 concentration Radiation Physical and Chemical Factors Antiseptics Disinfectants Antibiotics Growth factor analogs Antimicrobial Chemical Agents Long-term
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This note was uploaded on 10/25/2009 for the course BIO 2900 taught by Professor Ghiorse during the Fall '07 term at Cornell University (Engineering School).

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Lecture 14 - Lecture 14 Bacterial Growth Physical and...

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