Help with a question

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bio185
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Help with a question

Post by bio185 » Thu Mar 29, 2012 1:22 pm

I'm struggling with the following 2 questions. Can someone help please explain this to me? I'd really appreciate it.


Question 1

Two aquatic plants were grown in either water or water containing a microtubule inhibitor for 24 hours. The roots were dissected and stained for DNA. The researcher reported that in the microtubule-inhibited plant there were a much higher number of cells at metaphase.
Describe in details what the experimenter would have observed in each root and explain the reason for the observations. What do you think would happen if the ‘inhibited’ plants were returned to plain water?


Question 2
You have been given an enzyme E, a substrate S and a competitive inhibitor I and you have been asked to calculate the Km of the reaction in presence and absence of the inhibitor I. However after drawing the Michaelis Menten plot you observe that even at the maximum concentration of inhibitor that you have been given, the Vmax for the inhibited reaction is lower than the un-inhibited reaction
Describe how you would have derived the data for the Michaelis Menten plot, explain the reason why you are perplexed about the observation of the Vmax and suggest what you could do to resolve if you have been given the correct information about the nature of the inhibitor.

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JackBean
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Post by JackBean » Thu Mar 29, 2012 1:47 pm

1. what happens during metaphase? How is it related to the microtubules?

2. Are you sure there should be "that even at the maximum concentration of inhibitor that you have been given, the Vmax for the inhibited reaction is lower than the un-inhibited reaction"? Because in such question I would expect rather substrate, because with high inhibitor concentration it's quite logic, that you won't have as high Vmax as without inhibitor.
The simplest answer would be insuficient inhibitor concentration, but based on last sentence, it's probably not competitive inhibitor. However, from such vague description we can hardly say, what type of inhibitor it is.
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

girlie21
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Re: Help with a question

Post by girlie21 » Thu Mar 29, 2012 2:14 pm

YEAH BUT HOW WOULD YOU EXPLAIN THE RELATIONSHIP OF MICRO TUBULES INHIBITOR? WHAT IS THE ROLE OF MICROTUBULE??

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Post by girlie21 » Thu Mar 29, 2012 2:15 pm

I mean the role of microtubule inhibitor?*

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Re:

Post by girlie21 » Thu Mar 29, 2012 2:16 pm

JackBean wrote:1. what happens during metaphase? How is it related to the microtubules?

2. Are you sure there should be "that even at the maximum concentration of inhibitor that you have been given, the Vmax for the inhibited reaction is lower than the un-inhibited reaction"? Because in such question I would expect rather substrate, because with high inhibitor concentration it's quite logic, that you won't have as high Vmax as without inhibitor.
The simplest answer would be insuficient inhibitor concentration, but based on last sentence, it's probably not competitive inhibitor. However, from such vague description we can hardly say, what type of inhibitor it is.


what is the role of micro tuble inhibitor?

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JackBean
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Post by JackBean » Thu Mar 29, 2012 3:54 pm

The inhibitor probably breaks the microtubules. So, are microtubules needed for something during metaphase?
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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Post by cyanodave » Fri Mar 30, 2012 12:09 am

Correct me if I'm wrong, but don't the chromosomes attach to the poles of the cell via microtubules during metaphase, and are pulled by the microtubules to the poles during anaphase? if this is the case then an inhibitor would prevent the occurrence of anaphase because chromosomes would remain in the center, unable to be pulled to the sides.

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JackBean
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Re: Help with a question

Post by JackBean » Fri Mar 30, 2012 8:09 am

Image
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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