Flashcards
Microbiology VI
Flashcards do conjunto (21)
- 1Describe the process of binary fissionSeptum cleavage as cross-walls form between diving cells
Time for 1 division = generation time
Vibrio natriengens divide every 10 minutes - 2Why are bacterial growth curves referred to as semilogarithimic graphsAs the X axis is still linear
- 3How would one work out the generation time?n= # generations in time (t)
G= generation time
G=t/n - 4How would you calculate growth?N=No2^n
N=Final cell count
No=Initial cell count
n= #generations during period of exponential growth - 5How do you calculate n?n=(logN-logNo)/log2
- 6What is the lag phase?Time between inoculation into fresh media and arrival of significant growth
- 7What is exponential phase dictated by?Nutrient/space availability, genetic characteristic of the organism
Healthiest cell state - 8Growth rate at stationary phase?0
No net increase/decrease in cell numbers - 9What are the issues with microscope counting?Hard to distinguish between dead/alive cells
Debris could be mistaken for a cell - 10What is the viable countNumber of cells that are able to divide and produce offspring
- 11What is the major assumption of plate counting?1 colony = 1 cell
- 12What is the 2 methods to do this?Spread plate method / pour plate method
- 13What other problem arises with mixed cultures?Not all cells are optimised to grow in the same conditions.
- 14What are batch cultures?Microbes cultured in an enclosed vessel
A closed system
Typically a flask or tube - 15What are continuous cultures?An open system
Fresh media constantly flowing over growth vesel
Rate of flow in = rate of flow out
Steady state, growth vessels reach equilibrium with cell number, nutrients and waste - 16What are chemostats?Continuous cultures
Stirrers prevent sedimentation
Chemostat controls growth by controlling dilution rate - 17How is cell density regulated?Regulating concentration of a limiting nutrient i.e. C or N.
- 18Why must an equlibrium be reached?Too little dilution = cells die from starvation
Too high dilution = Cells can't grow fast enough and are washed out - 19Draw a diagram comparing batch cultures to continuous culturesbahjooobie
- 20How can you measure growth?Count cell number
Samples dried out into slides/liquid samples - 21What is a counting chamber used for?Counting liquid samples, akin to taking a punnet square and up-scaling from there
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- O usuário eliminou as informações de disciplina FlashCards sobre Microbiology VI, criado por Usuário eliminado em 25-04-2018.
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- Usuário eliminado · abr 2018
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- 25 abr 2018
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- Criado por J yadonknow · 22 jan 2018
- Copiado por J yadonknow · 25 abr 2018
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