L28 Flashcards
Why are some microbes dangerous
Have a very fast growth rate and those bacteria that survive antibiotics can proliferate very quickly
How long does cell doubling take
13 mins
How do microbes reproduce?
Binary fission, asexual reproduction
What happens in binary fission
Circular chromosome replicates, cell gets longer, cell cleaves in the middle
Why are prokaryotes so dominant
Have lived on this planet for 1.7 billion years, have been exposed to the different environments and has adapted + colonised different niches
Building blocks of microbes
Same building blocks as us, just in different amounts
What is a pure culture?
Just that bacteria on an Agar plate
What is a batch culture
Bacteria from pure batch in a closed system where no nutrients go in/out
Key phases of a closed batch system graph
*Lag phase
*Exponential phase
*Stationary phase
*Death phase
Lag phase
Lots of nutrients added in, time is required to get the biosynthetic reactions running
Exponential growth
Under ideal conditions where nothing is limiting growth, exponential growth pattern
Stationary phase
Nutrients used up and cells growing = cells dying
Cryptic growth where growing cells feed on dead ones
Death phase
Skew towards death
99.9% of cells die but 0.01% that survive can survive for a long time eg E. coli can last for years (other mechanism as it cant develop into an endospore)
What does no growth mean
Means death rate and groth rate are in balance
What do prokaryotes need to multiply?
Carbon source - to making building blocks and macromolecules
*Energy source –> from food taken in to ATP to drive catabolic and anabolic processes
*Reducing power - carriers of energy and electrons i.e NADPH
