Chapter 4 (Notes) Microbial Growth

Question 1

bacterial biofilms form when _____ are plentiful

Answer 1

nutrients - many different environmental signals also cause films to form

if scarce - individuals detach to forage for new sources

Question 2

biofilms can take many different….

Answer 2

forms and serve different functions for different species

Question 3

does a common pattern occur in biofilm formation

Answer 3

yes

Question 4

growth of microbes is inhibited by 3 things

Answer 4

resources (energy, nutrients)

competition

grazing

Question 5

phases of growth

Answer 5

lag phase

log phase

stationary phase

death phase

Question 6

what is k on the y-axis corresponding to the stationary phase?

Answer 6

the carrying capacity or final cell yield

Question 7

log phase is related to what

Answer 7

environmental conditions

Question 8

chemostat

Answer 8

continuous cultures

keeps cells growing exponentially at low concentrations of the limiting nutrient

Question 9

fastest growing microbe

Answer 9

hot springs bacterium g = 10 min

Question 10

slowest growing microbe

Answer 10

deep-sea sediment g = 100 yrs

Question 11

normal growth conditions

Answer 11

1 atm (sea level)

15-40 degrees C

pH neutral

salinity of 0-0.9 NaCl

aerobic conditions

Question 12

barophile

Answer 12

extreme pressure

> 380atm

Question 13

thermophile

Answer 13

high temp

> 40 degrees C

Question 14

psychrophile

Answer 14

low temp

Question 15

alkaliphile

Answer 15

high pH

> > 7

Question 16

acidophile

Answer 16

low pH

Question 17

halophile

Answer 17

high salinity

Question 18

metagenomics

Answer 18

sample from environment

Question 19

transcriptome

Answer 19

look at mRNA present; expressed genome

Question 20

Arrhenius Equation

Answer 20

k = Ae^(-Ea/RT)

k = rate constant

T = temp in K

Ea = activation energy

Question 21

bacteria faced with environmental stress undergo….

Answer 21

molecular reprogramming

eg. endospores of gram-pos, heterocysts of cyanobacteria, fruiting bodies, aerial hyphae and arthospores

Question 22

fruiting bodies

Answer 22

gliding motility

starvation triggers aggregation of 100,000 cells to form a fruiting body

Question 23

some fruiting bodies facilitate _____ dispersal

Answer 23

spore

Question 24

cyanobacterial heterocysts

Answer 24

specialized cells anabaena differentiate into

allows for N2 fixation anaerobically while maintaining oxygenic photosynthesis

Question 25

alpha protobacterium: caulobacter

Answer 25

dimorphic appendage

only stalked cells reproduce

swarmer cells –> stalked cells using regulatory CtrA

Question 26

aerial hyphae

Answer 26

as nutrients decline, these divide into arthrospores