Scorpio's Section Flashcards
how do bacteria reproduce?
via binary fission
what is generation time?
length of time required for a single bacterial cell to yield 2 daughter cells
what influences generation time for bacteria?
genetics & environmental factors
Bacterial growth undergoes 4 phases. Name each and describe them.
1) Lag phase: time when bacteria gathers the essential constituents in order to replicate.
2) Log phase: they replicate in exponential numbers
3) Stationary phase: no longer are increasing in #, plateau phase.
4) Decline phase: cell death is exponential. bacteria reproduced beyond nutrients provided by the agar so they die.
what is turbidity measurements?
its not sensitive; the extent of cloudiness is equivalent to the extent of bacterial cells. more cloudiness= lots of bacteria. no cloudiness= no bacteria.
What is Real-time PCR?
counting the # of bacterial cells in a sample quantified based on the detection of [DNA]. this technique is fast and accurate.
When it comes to bacterial nutrition, what kind of “-trophs” are they? And what does the name mean?
chemoheterotrophs- uses organic chemicals as sources of energy & carbon
Bacterial nutrition: most bacteria requires ____ & ____ in relatively large amounts.
carbon & nitrogen
In culture media what is the main source of nitrogen for bacteria?
peptones
What are three other things that bacteria require to grow in a medium?
phosphates, sulphates, & trace elements
What are growth factors?
these are essential substances required for biosynthesis
Growth of bacteria in culture is influenced by 5 things.
1) temperature
2) hydrogen ion concentration
3) availability of moisture
4) atmospheric composition
5) osmotic pressure
Definition: organisms with an optimum growth near 37 degrees C (body temp)
mesophiles
Definition: organisms with an optimum temp beween 45 - 70 degrees C
thermophiles
definition: archaea with an optimum T of 80 degrees or higher
extreme thermophiles or hyperthermophiles
definition: cold-loving organisms that can grow in a fridge
psychrophiles
Bacteria require ____ for growth, and species vary widely in their susceptibility to desiccation.
water
Bacterial cells in the environment are usually present in ____ solutions. In ____ solutions, bacterial cells undergo shrinkage.
hypotonic; hypertonic
Metabolism has an energy- generating component called _____.
catabolism
Metabolism has an energy-consuming component called _____.
anabolism
_____ rxns produce energy as ATP.
catabolic
_____ is energy temporarily conserved in “high energy bond”
ATP
What are the two ways cells can fundamentally produce ATP?
1) substrate level phosphorylation
2) electron transport phosphorylation
Simple: via glucose & respiration