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Micro Test - 5th Slides
Terms in this set (27)
Normal growth conditions are...
- sea level
- temperature of 20-40 degrees celsius
- Neutral pH
- 0.9% salt, and ample nutrients
Any ecological nich outside the window of normal growth conditions is called...
An organism that inhabits an extreme environment is called an...
The one main criterion that determines the invironmental habitat of a species is...
the tolerance of the organism's proteins and other macromolecular structures to the physical conditions within that niche
Growth rate doubles for every _______ rise in temperature
10 degrees celsius
Temperature growth range is usually...
30-40 degrees outside the organisms optimal growth range
"normal" growth conditions for microbes include all the following parameters except...
a) sea level
b) temp of 20-40 degrees
c) neutral ph
d) 3% salt
e) ample nutrients
Psychrophiles grow at temperatures...
Mesophiles grow at temperatures...
Thermophiles grow at temperatures...
Hyperthermophiles grow at temperatures...
What happens during heat-shock response?
produces chaperone proteins that help maintain protein shape and produces enzymes that are able to change membrane liquid composition
organisms adapted to grow at very high pressures
organisms that grow well over the range of 1-50 MPa, but thier growth falls off thereafter
require high salt conceptrations (usually between 10-20% NaCl
a measure of the number of solute molecules in a solution and is inversely related to Aw
membrane-channel proteins that allow water to traverse the membrane much faster than by diffusion
What do cells do in hypertonic solution?
bacteria protect their internal water by synthesizing or importing compatible solutes
What do cells do in hypotonic solution?
mechanosensitive channels are used to leak solutes out of the cell
Why can't bacteria grow in solutions with very high concentrations of sugar?
a) bacteria cannot digest pure sugar
b) sugar raises the solution's osmolarity
c) sugar lowers the solution's osmolarity
d) sugar raises the solution's pH
e) sugar lower the solution's pH
What do extreme of either hydronium or hydroxide ions do to cell growth?
limit cell growth
A bacterium tolerates a pH range of 3-10. This represents a __________ difference in H+ ion concentratoin
What can bacteria do to become resistant to disinfectants?
1) alter fatty acid synthesis protein normally targeted by triclosan
2) Produce membrane-spanning, multidrug efflux pumps
3) Form multispecies biofilms
the use of one microbe to control the growth of another
a type of biocontrol that contain certain microbes that, when ingested, aim to restore balance to intestinal flora
aims to treat infectious diseases with a virus targeted to the pathogen
Which physical agents are used to prevent bacterial growth?
a) pasteurization, freezing, and phages
b) irradiation, probiotics, and filtration
c) autoclaving, irradiation, and freezing
d) antibiotics, refrigeration, and pasteurization
e) irradiation, autoclaving, and disinfectants
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