Term
|
Definition
| an increase in cell numbers |
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Term
|
Definition
| change in cell number per unit time. |
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Term
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Definition
| The formation of two cells from one. |
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Term
|
Definition
amount of time required for the cell
number to double-also called the doubling time. |
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Term
|
Definition
| DNA replication, cell elongation, septum formation, completion of septum with formation of cell walls, cell separation |
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Term
|
Definition
| involved in cell division (make up the FTZ ring) |
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Term
|
Definition
an actin-like protein involved in cell shape
(cocci don’t have this protein) |
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Term
|
Definition
| signals the formation of the FTZ ring between nucleoids |
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Term
|
Definition
make holes in the cell wall as
new material is added. If the autolysins are active and new
peptidoglycan is not added then the cell will lyse |
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Term
|
Definition
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|
Term
New peptidoglycan is assembled from parts that are carried to the cell wall by what
two carrier molecules? |
|
Definition
1. Uridine diphosphate (UDP)
2. Bactoprenol; a C55 isoprenoid alcohol (a lipid). |
|
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Term
|
Definition
It is a lipid carrier molecule that transports peptidoglycan precursors across the cytoplasmic
membrane |
|
|
Term
| What is the function of vancomysin? |
|
Definition
Blocks the UDP-NAG-NAM complex from attaching to the peptidoglycan. binds to D-Ala-D-Ala and prevents incorporation of
the NAM and NAG into the cell wall. Thus prevents transpeptidation. |
|
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Term
|
Definition
blocks dephosphorylation of
Bactoprenol |
|
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Term
| Penicillin blocks which step in peptidoglycan synthesis? |
|
Definition
Transpeptidation.
Beta-lactam antibiotics block transpeptidation
so when the autolysins make holes in the
membrane and the cell tries to fill it in with new
peptidoglycan it can’t crosslink the glycan
chains and the cell lyses. Penicillin binds to FtsI |
|
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Term
|
Definition
| formation of Peptide crosslinks to make peptidoglycan. |
|
|
Term
When the growth of a bacterial population is plotted on semi-logarithmic graph paper,
the rate of growth is indicated by: |
|
Definition
|
|
Term
Plotting time vs. log(cell density) produces _______________.
a) straight line
b) exponential curve |
|
Definition
|
|
Term
| What are the 4 phases in growth curves? |
|
Definition
| Lag; exponential; stationary; death |
|
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Term
| How is growth rate calculated? |
|
Definition
| Change in cell number per unit time |
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Term
|
Definition
amount of biomass produced during bacterial growth on a given
substrate. |
|
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Term
|
Definition
| Grams of dry cell material produced per mole of ATP |
|
|
Term
| What are the 3 ways to measure microbial growth? |
|
Definition
A. Direct microscopic count
B. Viable count (colonies)
C. Cell mass (spectrophotometer).Turbidity. |
|
|
Term
| What factors affect the growth rate and growth yield? |
|
Definition
the growth medium: When a
cell has to make everything from scratch this requires
more energy and more time. Other factors include environmental factors like
temperature, water availability, osmolarity, and pH. |
|
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Term
|
Definition
When a culture is grown in a closed system with no
added nutrients and no waste removal; In batch cultures the conditions are constantly
changing because the bacteria are modifying the
growth medium as they grow |
|
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Term
|
Definition
| culture with constant food and waste removal. A STEADY STATE is established in culture |
|
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Term
|
Definition
| continuous cultures are grown in this |
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Term
|
Definition
used by to adjust the population
density by limiting the amount of a key nutrient. |
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Term
|
Definition
cold loving.
T-minimum at or below 0°C
T-optimum at or below 15°C
T-maximum below 20 ° C |
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Term
|
Definition
T-optimum =20-40
T-minimum at or below 0°C Don't grow well but do grow.
These are a problem for the food industry and in your refrigerator. |
|
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Term
| At ____°C all enzymatic reactions stop. |
|
Definition
|
|
Term
|
Definition
Organisms that live at the temperature range of warm blooded
mammals.
Minimum 10°C
Optimum about 37 (98.6°F)
Maximum about 45° |
|
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Term
|
Definition
| Optimum temp. is above 45°C |
|
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Term
|
Definition
Temp optimum above 80°
there are several habitats on earth where things live at temperatures near or above the
boiling point of water. Hot springs, deep sea vents.
1. Most thermophiles and hyperthermophiles are prokaryotes.
2. Most of these are Archaea.
3. Most phototrophic organisms are not thermophiles.
4. Complexity is inversely related to the ability to grow at high temps- |
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Term
|
Definition
Organisms that prefer low pH. Many fungi
prefer this. Also many bacteria are acidophiles. Many
sulfur bacteria produce sulfuric acid and therefore live at
very low pH. In these organisms, the plasma membrane
is stabilized by the H+ concentration and when shifted to
more neutral pH the membrane dissolves and the bacteria
lyse. |
|
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Term
|
Definition
Prefer high pH. Usually found in regions
with high carbonate deposits. -soda lakes. Not as many
as there are acidophiles. |
|
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Term
|
Definition
|
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Term
|
Definition
Grow optimally at normal salt concentrations (0.85%) but are able to
grow well at high salt concentrations (7.5%) |
|
|
Term
|
Definition
Organisms which grow optimally in salt concentrations equal to sea
water. (3% NaCl + many other minerals) |
|
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Term
|
Definition
Organisms that live in extremely salty environments some
actually grow on salt crystals. |
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Term
|
Definition
| Organisms that live in high sugar concentrations |
|
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Term
|
Definition
| Organisms that live in very dry environments. |
|
|
Term
| How do organisms live in low water availability |
|
Definition
They make compatible solutes: increase the
concentration of a solute inside the cell which is
compatible with the cell so the water does not move out
of the cell.
Examples of compatible solutes used by microbes are:
Proline, glutamate, some sugars, glycerol. |
|
|
Term
| example of halotolerant species |
|
Definition
Staphylococcus
epidermidis grows on your skin. |
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Term
|
Definition
|
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Term
|
Definition
| O2 Not needed but grow better |
|
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Term
|
Definition
Need O2 but at concentrations below those
found in the atmosphere |
|
|
Term
|
Definition
| Growth same in presence and absence of O2 |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Provides high surface area to volume ratio for growing cultures aerobically. |
|
|
Term
| examples of toxic oxygen species |
|
Definition
| superoxide; hydrogen peroxide; |
|
|
Term
|
Definition
Add 30% hydrogen peroxide to bacterial cells and
look for bubbles
Cells of the immune system produce hydrogen
peroxide to kill bacteria. Bacteria that produce catalase
are able to survive this chemical attack from the
immune system. |
|
|
Term
| Catalase is a __________ factor |
|
Definition
|
|
Term
| Obligate anaerobes can be found in three groups: |
|
Definition
Many
bacteria, a few fungi, and a few protozoa. |
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