VCE Biology Question Thread

[SmartWorker]

Hey,

What would the transduction of a hydrophobic signalling molecule be?

I understand
1. The non-polar molecule binds to an intracellular receptor.
2. Transduction :  ?? (idk what should be here?)
3. Cellular Receptor: the signal-receptor complex acts as a transcription factor altering gene expression may result in production of a protein.

[angrybiscuit]

Hey,

What would the transduction of a hydrophobic signalling molecule be?

I understand
1. The non-polar molecule binds to an intracellular receptor.
2. Transduction :  ?? (idk what should be here?)
3. Cellular Receptor: the signal-receptor complex acts as a transcription factor altering gene expression may result in production of a protein.

Technically, there's no signal transduction in hydrophobic molecules because there is no formation secondary messengers to amplify the signal. But my understanding is their form of signal transduction is a conformational change in the receptor. So when the hydrophobic molecule binds to the receptor, the receptor has a conformational change turning it into a transcription factor. Not 100% on that however but there is definitely no secondary messengers formed

[Chocolatepistachio]

For this question would this be right
What does the term substrate mean when considering enzyme action.
- The substances that help the enzyme to react

[SmartWorker]

For this question would this be right
What does the term substrate mean when considering enzyme action.
- The substances that help the enzyme to react

I would say the molecule or substance that binds to the active site of the enzyme.

[Chocolatepistachio]

Thanks
For this question would this be right
What property would a substance that inhibits a specific enzyme need to have?
- The substance would need to have the same shape to be able to fit into the active site.

[55232Jeremy]

Thanks
For this question would this be right
What property would a substance that inhibits a specific enzyme need to have?
- The substance would need to have the same shape to be able to fit into the active site.

You should say the inhibitor has a complementary shape to the substrate or to the enzyme's specific active site. VCAA will mark you down for not using the word 'complementary' in questions like these.

[WhatisaMeMe]

Hi can anyone please explain why 2014 VCAA exam question 12 is D and not B thanks
is it because some atp is already made as it is broken into pyruvic acid?

[angrybiscuit]

Hi can anyone please explain why 2014 VCAA exam question 12 is D and not B thanks
is it because some atp is already made as it is broken into pyruvic acid?

It is not B because under anaerobic conditions, pyruvate is converted into lactic acid not acetyl coA. Pyruvate is converted into acetyl coA only under aerobic conditions. D is the answer because fatty acids form more acetyl-coA than from glucose (or by process of elimination because other three aren't correct).

[Bri MT]

It is not B because under anaerobic conditions, pyruvate is converted into lactic acid not acetyl coA. Pyruvate is converted into acetyl coA only under aerobic conditions. D is the answer because fatty acids form more acetyl-coA than from glucose (or by process of elimination because other three aren't correct).

To add to this, we're told that you get 8 acetyl CoA from 1 fatty acid which is much much more than from 1 glucose (each pyruvate only goes to 1 acetyl CoA)

[Chocolatepistachio]

If someone could help with this question
When separated by a selectively permeable membrane a net gain of water tends to occur in
A a hypoosmotic solution from an isosmotic solution
B an isosmotic solution from a hyperosmotic solution
C a hyperosmotic solution from a hypoosmotic solution
D a hypoosmotic solution from a hyperosmotic solution

[homeworkisapotato]

If someone could help with this question
When separated by a selectively permeable membrane a net gain of water tends to occur in
A a hypoosmotic solution from an isosmotic solution
B an isosmotic solution from a hyperosmotic solution
C a hyperosmotic solution from a hypoosmotic solution
D a hypoosmotic solution from a hyperosmotic solution

I'd say it's C. That's because as osmosis is passive movement, water moves from high concentration to low concentration. Hypotonic solutions contain a larger concentration of water and hypertonic contain a smaller concentration of water (larger conc of solute) so water from hypotonic solution moves to hypertonic solution. Hope this helps and I explained it properly (considering that I have my Bio exam day after tomorrow  )

[wingdings2791]

Hello guys, can anyone clarify why the answer diagram for 9bii on the VCAA 2017 exam doesn't include the restriction sites for BamHI, even though the question specifically asked to 'include the position of the recognition sites for the restriction enzymes EcoRI, HindIII, and BamHI on the plasmid'? Should it be assumed that the recognition site is destroyed when cut by BamHI? Thanks

[55232Jeremy]

Hello guys, can anyone clarify why the answer diagram for 9bii on the VCAA 2017 exam doesn't include the restriction sites for BamHI, even though the question specifically asked to 'include the position of the recognition sites for the restriction enzymes EcoRI, HindIII, and BamHI on the plasmid'? Should it be assumed that the recognition site is destroyed when cut by BamHI? Thanks

BamHI is the restriction enzyme which is used to cut at that specific recognition site of the plasmid in order to insert that specific human gene which was also cut by BamHI presumably. Therefore, there is no need to include the BamHI recognition site as the gene is what is being inserted into the plasmid to attach to complementary nucleotides.

[wingdings2791]

BamHI is the restriction enzyme which is used to cut at that specific recognition site of the plasmid in order to insert that specific human gene which was also cut by BamHI presumably. Therefore, there is no need to include the BamHI recognition site as the gene is what is being inserted into the plasmid to attach to complementary nucleotides.

Okay thanks, just thought it was a bit bizarre that they said to include it in the question lol

[55232Jeremy]

Okay thanks, just thought it was a bit bizarre that they said to include it in the question lol

They stated the 'position' of it so they are purely trying to ask where that gene of interest is being inserted into, not to simply label BamHI.