Term
| How does temperature affect proteins? |
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Definition
| Heat denatures and disrupts proteins, resulting in loss of tertiary structure and biological activity. |
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Term
| Can nucleic acids be damaged by heat? |
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Definition
Yes!
Results: loss of DNA and RNA structure. |
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Term
| What happens if there is loss of nucleic acids? |
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Definition
No cell division or protein synthesis
=> cell death |
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Term
| What other molecules can be damaged by heat? |
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Definition
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Term
| Why are some organisms more resistent to heat than others? |
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Definition
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Term
| Why are endospores resistent to heat? |
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Definition
1. much lower water content than vegetative cells
(water is unavailable for chemical reactions that can damage macromolecules, coenzymes and others)
2. contain calcium dipicolinate
(further prevents induced denaturation of proteins)
3. specific proteins bind to nucleic acids and prevent their denaturation |
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Term
| What is the thermal death point (TDP)? |
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Definition
| lowest temp at which a population of a target organism is killed in 10 min |
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Term
| What is the thermal death time (TDT)? |
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Definition
| the shortest time required to kill a suspension of cells/spores under defined conditions at a given temperature. |
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Term
| What is the importance of inoculating a control plate? |
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Definition
1. for comparison
2. to make sure the bacteria is capable of growth |
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Term
Why is a bacteria that has
a high TDP and a long TDT
NOT classified as a thermophile? |
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Definition
| It's a mesophile, but would be killed at high temp. Endospores, however, are extremely heat resistent. |
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Term
| Eg. diseases caused by spore-forming bacteria... |
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Definition
1. anthrax
2. tetanus
3. botulism
4. gas gangrene |
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