Lecture 18: Microbial Growth

Question 1

defined medium

Answer 1

know exactly what went in

Question 2

complexed medium

Answer 2

composition unknown

Question 3

minimal medium

Answer 3

meets minimum requirements

Question 4

selective medium

Answer 4

favours growth of desirables & restricts growth of undesirables

Question 5

differential medium

Answer 5

distinguished between types

Question 6

why is agar used in the lab?

Answer 6

remains firm below 65 degrees and is hard for microbes to digest

Question 7

batch

Answer 7

liquid culture in a vessel

Question 8

are batch open or closed systems

Answer 8

closed

Question 9

what is 1 negative of batch?

Answer 9

limited growth

Question 10

lag phase

Answer 10

bacteria is adapting to new environment

Question 11

exponential phase

Answer 11

when most active growth occurs

Question 12

stationary phase

Answer 12

when no active growth & balancing cell death & division

Question 13

declining phase

Answer 13

bacteria runs out of resources to survive

Question 14

chemostat

Answer 14

continuous system where bacteria is fed with fresh medium

Question 15

is chemostat open or closed system

Answer 15

open

Question 16

what controls growth rate in chemostats?

Answer 16

dilution rate

Question 17

what does chemostat control?

Answer 17

growth rate & yield

Question 18

what is goal of chemostat

Answer 18

to keep bacteria in their exponential phase

Question 19

biofilms

Answer 19

attached communities

Question 20

T of F: biofilms can be closed or open systems

Answer 20

true

Question 21

how are growth curves established?

Answer 21

measures growth & population

Question 22

example of direct count method for bacteria

Answer 22

microscope

Question 23

2 examples of viable count method for bacteria

Answer 23

spread-plate & pour-plate

Question 24

what must be done during spread/pour plate methods in order to be able to count the bacteria?

Answer 24

dilution

Question 25

what is turbidimetric?

Answer 25

optical density to count bacteria

Question 26

how does optical density work for counting bacteria?

Answer 26

uses light pass to through & measure density of bacteria blocking the light

Question 27

what kind of count does optical density give?

Answer 27

total count of population

Question 28

what does colony forming unit (CFU) tell us?

Answer 28

viable count

Question 29

what 2 things double during cell growth?

Answer 29

cell mass & cell number

Question 30

what type of graph is growth plotted on?

Answer 30

semi-log scale

Question 31

generation time

Answer 31

amount of time it takes to double population

Question 32

specific growth rate

Answer 32

rate at a specific time

Question 33

psychorophile temp requirement

Answer 33

below 0 - 10

Question 34

mesophile temp requirement

Answer 34

10 - 50

Question 35

psychotolerant temp requirement

Answer 35

0-42

Question 36

thermotolerant temp requirement

Answer 36

10-55

Question 37

thermophile

Answer 37

40-70

Question 38

hyperthermophile temp requirement

Answer 38

90-115

Question 39

neutrophile pH range

Answer 39

5.5 - 8

Question 40

acidophile pH range

Answer 40

0- 5.5

Question 41

Alkaliphile pH range

Answer 41

8- 14

Question 42

halotolerant NaCl % range

Answer 42

0-11 %

Question 43

nonhalotolerant NaCl % range

Answer 43

1-2 %

Question 44

halophile NaCl % range

Answer 44

0-12%

Question 45

extreme halophile NaCl % range

Answer 45

10 % +

Question 46

what does Thioglycolate do?

Answer 46

reduces O2 concentration

Question 47

obligate aerobe vs obligate anaerobe

Answer 47

aerobe- grows @ top anaerobe- grows @ bottom

Question 48

facultative anaerobe/aerobe

Answer 48

grows best at top but can also grow at bottom

Question 49

microaerophillic

Answer 49

grows in between levels

Question 50

aerotolerant anaerobe

Answer 50

grows everywhere

Question 51

oxic vs anoxic zone

Answer 51

oxic- top anoxic- bottom

Question 52

candle jar method

Answer 52

chemical reaction inside a jar to remove O2

Question 53

what type of viruses can cause plaque formation?

Answer 53

lytic

Question 54

what do viruses need in order to be grown?

Answer 54

living host cells