9 + 10 Flashcards
most bacteria exist within a ________ and is held tgt by a sticky matrix of ___ + ____ + ____
biofilm = complex community of bacteria
attaches to & grows on surface
polysac / protein / DNA
4 classes of optimal growth temperature
1/ psychrophiles: deep water 5C, aquatic species
2/ thermophiles: 60C, compost host and hot spring
3/ mesophile, best characterized: grow in warm blooded creatures / soil & aquatic environments of tropic regions
4/ hyperthermophiles: 95C
distinct btw obligate aerobe / obligate anaerobe / facultative anaerobe / aerotolerate anerobe / microaerophile
1/ requires O2 2/ intolerates O2 3/ grows best in o2 but can grow without 4/ insensitrive to O2 4/ requires very lil air
distinct btw acidophiles / neutrophile / extreme acidophile
acidophile: pH 5 (useful in food industry e.g active culture on yogurt)
neutrophile: pH near 7, can grow both in (a) & (b) environemnt
extrme acidophile: pH 1-2; some archeal species
how are some bacteria able to remain metabolically inactive?
1/ when enviroments became unfavouurable, become slow and non-dividing/growing
=. can even escape antibiotics
2/ endospores: desiccation has lil effect
remain viable even under boiling water, ethanol, radiation
+. durable
describe the bacterial population growth curve
Lag phase: adapt to new environment, change nutr condition; legth depend on metabolic activity in micro pop
Log phase: enter active growth (all cell undergo repeated cell cycle)
Stationary phase: O2 & nutr becomes depleted, waste accumulates (cell remain alive but stop divind)
Decline phase: if nutr not replenished, protein sysnthesis stop, celles behin to die
stationary phase vs decline phase
with stationary phase, cells are still alive but nondividing . with later, cell begin to die.
(1) O2 + nutr become depleted (2) not replenished
if a bacteria is insensitive to O2 / can survive in 60C / ph = 5, what is it?
aerotolerate anaerobe, thermophile, acidphophile
if a bacteria requires lil O2 + but need high salt concentration and grow in 95C, what is it?
micraerophile / halophile / hyperthermophile
if bacteria can grow in both acidic/alkalinic environemnt with water moving the cell and deep water 5C?
neutrophile / in non-saline environment / psychrophile
what is the first stage of cell cycle?
metabolic growth: cell < in mass _ size / enzymes splitting the bonds in cell wall, glycan layer so cells able to stretch and exapnd
synthesis of protein, phospholipid , others
check point
in DNA replication- 2nd stage of cell cycle- what do the bacteria create and how?
DNA! by copying bacterial chromosome
have 2 identical copy in a cell and split
checkpoint!
what happens in binary fission?
partition forms @ mid 0cell & cells split in half (cytokinesis)
cytoskeleton protein forms fission ring apparatus to enrure 2 nearly equal daughter cells are formed
speed of septum material dissolves determines aggregation
how does microbe grow/
through sexual production- forming new cells while maintaining genetic consistency
what does enzyme do?
< the probability of the rxn happening (w.o being consumed by rxn itself)
=> lowers activation E needed for rxn
is highly specific: target 1 rxn
has an active site
requires in lil amount bcs can be reused
