microbial growth pt1 Flashcards
1
Q
name some factors affecting microbial growth
A
- temperature
- pH
- nutrient availability
- aeration - oxygen and co2
2
Q
what organisms are known as heat lovers?
A
- thermophiles
- hyperthermophiles
3
Q
what are psychrophiles?
A
- cold loving organisms
4
Q
what pH do most fungi grow at?
A
- 5
5
Q
examples of microaerophiles
A
- anaerobes
- aerobes
6
Q
how does the growth rate of microorganisms increase?
A
- with increasing water content of substrates
7
Q
what is water availability dependant on?
A
- solutes including
: salts
: sugars
: other substances that are dissolved in water
8
Q
list some stressful environmental conditions
A
- presence of toxic substances
- lack of nutrients
- temperature
9
Q
what are certain survival structures (spores) in bacteria and fungi ?
A
- cysts in bacteria
- sclerotia in fungi
10
Q
what are the 4 phases in population growth ?
A
- lag phase
- exponential phase
- stationary phase
- death phase
11
Q
why do fungi produce spores?
A
for survival and dispersal
12
Q
what are the 2 main types of spores?
A
- sexual and asexual
13
Q
list some characteristics of sexual spores
A
- thick walled
- resistant to unfavourable environmental conditions
14
Q
characteristics of asexual spores
A
- produced in large numbers for dispersal
- low resistance to unfavourable conditions
15
Q
what is a characteristic of a bacterial endospore?
A
- v resistant life form
- able to withstand temperatures above boiling point of water (thermophile)
- can remain viable in a metabolically inactive state for 300yrs
16
Q
what large amounts of a compound do bacterial endospores have?
A
- calcium dipicolinate
17
Q
A
