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March 28, 2024, 11:10:49 pm

Author Topic: VCE Biology Question Thread  (Read 3570468 times)  Share 

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nerdmmb

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Re: VCE Biology Question Thread
« Reply #345 on: January 27, 2014, 02:05:13 pm »
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Because the cells are where the vast majority of biochemical processes are carried out

Thanks alondouek!

nerdmmb

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Re: VCE Biology Question Thread
« Reply #346 on: January 27, 2014, 07:40:17 pm »
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I was a bit confused about the function of enzymes. According to my textbook, enzymes reduce activation energy however have no effect on the rest of the reaction. Is this true? If so, when people say that enzymes catalyse a reaction, do they actually mean that enzymes catalyse the beginning of a reaction?

Thank-you and sorry about the confusion!

vox nihili

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Re: VCE Biology Question Thread
« Reply #347 on: January 27, 2014, 07:49:13 pm »
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I was a bit confused about the function of enzymes. According to my textbook, enzymes reduce activation energy however have no effect on the rest of the reaction. Is this true? If so, when people say that enzymes catalyse a reaction, do they actually mean that enzymes catalyse the beginning of a reaction?

Thank-you and sorry about the confusion!

It depends on the type of enzyme really. It's hard to explain, because it's kind of true and kind of not. Some enzymes just orient things better, and that reduces the activation energy, whereas others actually press and hold substrates together, and thereby participate in the whole reaction. Just presume that reactions are instantaneous (each individual step that is).
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MM1

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Re: VCE Biology Question Thread
« Reply #348 on: January 27, 2014, 09:36:46 pm »
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What do we need to know about rational drug design?

vox nihili

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Re: VCE Biology Question Thread
« Reply #349 on: January 27, 2014, 09:41:47 pm »
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What do we need to know about rational drug design?

What it is.
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nerdmmb

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Re: VCE Biology Question Thread
« Reply #350 on: January 27, 2014, 09:45:28 pm »
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To what extent do we need to know about thermophilic bacteria?

alondouek

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Re: VCE Biology Question Thread
« Reply #351 on: January 27, 2014, 09:53:07 pm »
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To what extent do we need to know about thermophilic bacteria?

Probably nothing beyond the fact that they are bacteria that thrive in higher temperatures.
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nerdmmb

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Re: VCE Biology Question Thread
« Reply #352 on: January 27, 2014, 10:20:54 pm »
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Why is it that competitive chemical inhibitors will stop binding to an enzyme if there is a build-up of substrates?
Why don't non-competitive inhibitors also stop binding?

howlingwisdom

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Re: VCE Biology Question Thread
« Reply #353 on: January 27, 2014, 10:35:56 pm »
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Can digestive enzymes also be called hydrolytic enzymes? (Or is it best just to refer them as the former?)
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alondouek

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Re: VCE Biology Question Thread
« Reply #354 on: January 27, 2014, 10:55:05 pm »
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Why is it that competitive chemical inhibitors will stop binding to an enzyme if there is a build-up of substrates?
Why don't non-competitive inhibitors also stop binding?

A competitive inhibitor binds to the enzyme's active site. We can reverse this inhibition by increasing substrate concentration, as the substrate can essentially "overpower" the effect of the inhibitor by occupying the active site instead, in a way 'forcing' the inhibitor out of the active site (remember that the enzyme in this scenario is specific to both the substrate and the competitive inhibitor).

Non-competitive inhibitors do also stop binding (I think you may have made a small error in the question :) ), but this form of inhibition is not considered reversible (within the bounds of the VCE curriculum) because the inhibitor binds to a site OTHER than the active site. This distorts the shape of the enzyme's active site, which means that increasing substrate concentration will have no effect because the substrate cannot bind to the active site.

Can digestive enzymes also be called hydrolytic enzymes? (Or is it best just to refer them as the former?)

All digestive enzymes are hydrolytic (the belong to the class of enzymes known as hydrolases), so that's fine!
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MM1

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Re: VCE Biology Question Thread
« Reply #355 on: January 28, 2014, 01:49:57 pm »
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Where does the energy to make ATP from ADP+Pi come from? Since it's an anabolic reaction.

vox nihili

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Re: VCE Biology Question Thread
« Reply #356 on: January 28, 2014, 05:54:05 pm »
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Where does the energy to make ATP from ADP+Pi come from? Since it's an anabolic reaction.

Breaking down sugars, fats etc. Because they release energy, the break down of them is used to fuel the reaction between ADP and inorganic phosphate.
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alchemy

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Re: VCE Biology Question Thread
« Reply #357 on: January 28, 2014, 05:56:50 pm »
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Where does the energy to make ATP from ADP+Pi come from? Since it's an anabolic reaction.

Oxidative phosphorylation, which is the formal term for what T-Rav mentioned above.
« Last Edit: January 28, 2014, 05:58:26 pm by alchemy »

nerdmmb

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Re: VCE Biology Question Thread
« Reply #358 on: January 28, 2014, 06:55:40 pm »
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According to my textbook, useful molecules diffuse back into the cytoplasm from the lysosome. How is this possible?

Also, how do the hydrolytic enzymes in the lysosomes break down foreign debris when the enzyme and substrate are meant to be specific?

Thanks :)

Chang Feng

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Re: VCE Biology Question Thread
« Reply #359 on: January 28, 2014, 07:26:10 pm »
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For the first part- i think its because the lysosome brakes down all the complex molecules so the simpler ones can then be used by the cell again to build other different more complex molecules (that require the same sub-units). just guessing from my limited knowledge, otherwise no idea. and for the second part not too sure either.
I was just wondering for the disease chapter, what are we required to know about each different agent/ pathogen- (eg there name, function)? thanks.