Penicillin activity on bacteria in different conditions

About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.

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klapausius
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Penicillin activity on bacteria in different conditions

Post by klapausius » Wed Sep 22, 2010 12:02 pm

Q2
Although penicillin inhibits peptidoglycan synthesis, bacterial cells will continue to grow normally in the presence of penicillin in a(n) ____ environment
1. Hypotonic
2. Isotonic
3. Hypertonic
4. Nonpolar

my guess is (3) hypertonic, as bacteria can still survive and not shrink in that cond. as they posses cell wall also in that cond., the penicillin will not be able to enter the cell
im not sure if my explanations are correct, pls help me thanx

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JackBean
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Post by JackBean » Wed Sep 22, 2010 12:07 pm

I would say isotonic because in such enviroment they won't rupture, althrough their cell wall will be broken?
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

klapausius
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Re: Penicillin activity on bacteria in different conditions

Post by klapausius » Wed Sep 22, 2010 12:47 pm

so you are saying they would still survive w/o the cell wall as they still have an intact plasma membrane?
thanx jack

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biohazard
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Post by biohazard » Wed Sep 22, 2010 1:20 pm

Many cell-walled cells (including bacteria) can survive with only their plasma membrane intact in isotonic environments.

They even have a name for such a cell: a spheroblast, which is quite descriptive actually. Without the cell wall supporting the cell, even bacteria of different shapes tend to become round, because it is mostly the cell wall that gives them a shape.

klapausius
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Re: Penicillin activity on bacteria in different conditions

Post by klapausius » Thu Sep 23, 2010 12:38 pm

thank you biohazard, really appreciate yr explaination! now i understand better

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