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March 28, 2024, 09:52:15 pm

Author Topic: VCE Biology Question Thread  (Read 3570420 times)  Share 

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MM1

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Re: VCE Biology Question Thread
« Reply #645 on: February 16, 2014, 08:16:12 pm »
+1
wait, so has the study design from last year changed?

No, the current SD is from 2013-2016.

katiesaliba

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Re: VCE Biology Question Thread
« Reply #646 on: February 16, 2014, 08:42:14 pm »
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Hydrochloric acid denatures amylase due to it's high pH. This pH change therefore permanently distorts amylase's conformational shape due to the breaking of ionic bonds in the enzyme's tertiary structure. Amylase's active site is consequently destroyed and enzyme-substrate complexes will fail to form.

Does this cover Hydrochloric acid's effect on amylase entirely?
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alchemy

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Re: VCE Biology Question Thread
« Reply #647 on: February 16, 2014, 08:54:48 pm »
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Hydrochloric acid denatures amylase due to it's high pH. This pH change therefore permanently distorts amylase's conformational shape due to the breaking of ionic bonds in the enzyme's tertiary structure. Amylase's active site is consequently destroyed and enzyme-substrate complexes will fail to form.

Does this cover Hydrochloric acid's effect on amylase entirely?

Yes, but it's not only the ionic bonds that break in the protein's (enzyme's) tertiary structure. When an enzyme is denatured, all its bonds are broken; this includes the hydrophobic interactions, that hold a protein's tertiary structure, and the covalent bonds that form between cysteine residues (disulphide bridges).  You don't have to mention all of this, obviously, but just don't restrict your explanation to the breakage of ionic bonds only.

EDIT: Thanks again T-Rav!
« Last Edit: February 16, 2014, 09:05:42 pm by alchemy »

alchemy

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Re: VCE Biology Question Thread
« Reply #648 on: February 16, 2014, 08:56:56 pm »
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Apparently it's been taken out of the study design [globular and fibrous proteins], but I think it'll be good to know a few examples :)

I thought they were taken out too, but they cropped up on Checkpoints 2013... I'm still not sure why :C

vox nihili

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Re: VCE Biology Question Thread
« Reply #649 on: February 16, 2014, 09:04:14 pm »
+1
Yes, but it's not only the ionic bonds that break in the protein's (enzyme's) tertiary structure. When an enzyme is denatured, all its bonds are broken; this includes the hydrophobic interactions, that hold a protein's tertiary structure, and the covalent bonds that form between cysteine residues (disulphide bridges).  You don't have to mention all of this, obviously, but just don't restrict your explanation to the breakage of ionic bonds only.

This is not always true, but in the ballpark. In most cases, disulphide bridges probably won't actually break. They're a covalent bond just like the peptide bonds, so they're actually quite strong.

Otherwise, you're actually right and the gist of what you're saying is completely correct.
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katiesaliba

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Re: VCE Biology Question Thread
« Reply #650 on: February 16, 2014, 09:06:00 pm »
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Yes, but it's not only the ionic bonds that break in the protein's (enzyme's) tertiary structure. When an enzyme is denatured, all its bonds are broken; this includes the hydrophobic interactions, that hold a protein's tertiary structure, and the covalent bonds that form between cysteine residues (disulphide bridges).  You don't have to mention all of this, obviously, but just don't restrict your explanation to the breakage of ionic bonds only.

Thank you! It's just that my checkpoints book only specified that ionic bonds break in pH denaturing. So to clarify, when an enzyme becomes denatured, which bonds break? Checkpoints also wrote that only hydrogen bonds and Van Der Waals forces break in high temperature denaturation...is this right? Also, is pH denaturation reversible?
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alchemy

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Re: VCE Biology Question Thread
« Reply #651 on: February 16, 2014, 09:12:43 pm »
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Thank you! It's just that my checkpoints book only specified that ionic bonds break in pH denaturing. So to clarify, when an enzyme becomes denatured, which bonds break? Checkpoints also wrote that only hydrogen bonds and Van Der Waals forces break in high temperature denaturation...is this right? Also, is pH denaturation reversible?

Yeah, Checkpoints answers are like that sometimes which goes to show that you probably won't lose marks for mentioning that.
Yes, only Hydrogen bonds and Van Der Waals forces break in high temp denaturation. As Mr.T-Rav mentioned above, covalent bonds aren't likely to break even at high temps or extreme pH levels.

vox nihili

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Re: VCE Biology Question Thread
« Reply #652 on: February 16, 2014, 09:32:36 pm »
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Thank you! It's just that my checkpoints book only specified that ionic bonds break in pH denaturing. So to clarify, when an enzyme becomes denatured, which bonds break? Checkpoints also wrote that only hydrogen bonds and Van Der Waals forces break in high temperature denaturation...is this right? Also, is pH denaturation reversible?
Thank you! It's just that my checkpoints book only specified that ionic bonds break in pH denaturing. So to clarify, when an enzyme becomes denatured, which bonds break? Checkpoints also wrote that only hydrogen bonds and Van Der Waals forces break in high temperature denaturation...is this right? Also, is pH denaturation reversible?

I'd love for someone to confirm, because perhaps I'm missing something, but I think Checkpoints is quite wrong here...
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rery

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Re: VCE Biology Question Thread
« Reply #653 on: February 16, 2014, 09:36:52 pm »
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I'd love for someone to confirm, because perhaps I'm missing something, but I think Checkpoints is quite wrong here...

From memory biology 3/4 resources often refer to ionic interactions as bonds

alchemy

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Re: VCE Biology Question Thread
« Reply #654 on: February 16, 2014, 09:44:27 pm »
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Thank you! It's just that my checkpoints book only specified that ionic bonds break in pH denaturing. So to clarify, when an enzyme becomes denatured, which bonds break? Checkpoints also wrote that only hydrogen bonds and Van Der Waals forces break in high temperature denaturation...is this right? Also, is pH denaturation reversible?

What CP edition and page is this question on?

grannysmith

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Re: VCE Biology Question Thread
« Reply #655 on: February 16, 2014, 09:48:39 pm »
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Is it actually necessary to mention the breaking of bonds when defining denaturation? Is it enough to say: denaturation is the process by which a protein permanently loses its conformational shape and hence its function, through a change in temperature or pH beyond that of its optimum level.

MM1

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Re: VCE Biology Question Thread
« Reply #656 on: February 16, 2014, 09:52:02 pm »
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Is it actually necessary to mention the breaking of bonds when defining denaturation? Is it enough to say: denaturation is the process by which a protein permanently loses its conformational shape and hence its function, through a change in temperature or pH beyond that of its optimum level.

I think you should mention the breakage of bonds because you've got to explain how it loses its conformational shape.

Chang Feng

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Re: VCE Biology Question Thread
« Reply #657 on: February 16, 2014, 10:12:35 pm »
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Also about this. I just thought  then when enzymes are raised below or above temperatures (but not to the extent that it will denature), do bonds still break??? And if so how did they reform when temperate/ other deviation is returned to optimal temperature. If bonds don't break then how do enzymes lose their functions??  Thanks

alchemy

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Re: VCE Biology Question Thread
« Reply #658 on: February 16, 2014, 10:36:23 pm »
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Also about this. I just thought  then when enzymes are raised below or above temperatures (but not to the extent that it will denature), do bonds still break??? And if so how did they reform when temperate/ other deviation is returned to optimal temperature. If bonds don't break then how do enzymes lose their functions??  Thanks

Firstly, at low temperatures bonds don't break and the enzyme doesn't denature. Once an enzyme has denatured, it cannot return to its original shape. Bonds do break at high temperatures and at extreme pH's, and therefore the enzyme loses it's original function.

katiesaliba

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Re: VCE Biology Question Thread
« Reply #659 on: February 16, 2014, 10:47:45 pm »
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What CP edition and page is this question on?

2014 checkpoints page 177, question 2-22
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