VCE Biology Question Thread

[EllingtonFeint]

q.
Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

So this is due to different regulatory genes in different organs which will express different proteins, right?

any other reasons??

[PhoenixxFire]

q.
Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

So this is due to different regulatory genes in different organs which will express different proteins, right?

I remember that question - VCAA question yeah? Was there more context to it?

Depends on the context of the question. Expression of different proteins could be considered correct or it might want you to talk about alternative splicing

[galaxy21]

q.
Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

So this is due to different regulatory genes in different organs which will express different proteins, right?

If the somatic cells are all in the same organism, they are all going to be genetically identical (except for mutations of course) and therefore should have the same regulatory genes.
It would probably more related to the alternate splicing, where exons are rearranged (and sometimes spliced out) and alternate folding, which would result in different structures and therefore result in distinct proteins.
Different proteins from different genes could also be produced by different cells as each will have different needs for them .

[EllingtonFeint]

I remember that question - VCAA question yeah? Was there more context to it?

Depends on the context of the question. Expression of different proteins could be considered correct or it might want you to talk about alternative splicing

yeah, here's the full q and info...

c. In the rat pituitary gland, GC stimulates the production of the growth hormone protein. However, in the rat liver, GC stimulates the production of the enzyme tryptophan oxygenase.
Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.


are there any other reasons? So, alternate splicing, diff regulatory genes...

[randy123]

q.
Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.

So this is due to different regulatory genes in different organs which will express different proteins, right?

any other reasons??

The question is asking you to talk about intron retention and exon juggling,

intron retention: when some introns are not removed in post transcription modification

Exon juggling: when exons are rearranged

These both would result in a different protein being produced, another way is that the polypeptide chain could be folded in a different way, resulting in a different protein being produced

hope this helps

[Hirul1280]

Would you consider different mRNA sequences (different promoter regions) as a reason?

[EllingtonFeint]

Is facilitated diffusion always moving down a concentration gradient?

[PhoenixxFire]

yeah, here's the full q and info...

c. In the rat pituitary gland, GC stimulates the production of the growth hormone protein. However, in the rat liver, GC stimulates the production of the enzyme tryptophan oxygenase.
Given that the genetic sequence is identical in all somatic rat cells, explain how the production of distinct proteins in different cell types could occur.


are there any other reasons? So, alternate splicing, diff regulatory genes...

Yeah I thought it was that question. It actually wants you to talk about different signal transduction pathways occurring in different cells.

Would you consider different mRNA sequences (different promoter regions) as a reason?

Nah that’s not a thing in VCE

Is facilitated diffusion always moving down a concentration gradient?

Yep. Think of concentration gradients like a playground slide. It’s going to take effort to climb back up it but you can go down it easily.

[galaxy21]

Is facilitated diffusion always moving down a concentration gradient?

Yes - Active transport is the only one going against the concentration gradient.
Facilitated diffusion does not use energy so can only move down the concentration gradient from high to low concentration.

[AISHAB]

Could someone please explain signal transduction pathways? Do we need to know it in as much detail as Douch speaks about on Edrolo?

[PhoenixxFire]

Could someone please explain signal transduction pathways? Do we need to know it in as much detail as Douch speaks about on Edrolo?

I think Douchy talks about G proteins? You don’t need to know about that.

Just need to know the three steps (reception, transduction, response) and that different transduction pathways can result in different reaponses to the same signalling molecule

[Erutepa]

Would you consider different mRNA sequences (different promoter regions) as a reason?

As both cells would have identical genomes, they would not have different promoter regions, so you probably shouldn't say that.
If you mean the transcription from different promotor regions, that would be correct, but you need to explain how that would happen which gets you talking about differences in signal transduction (as PhoenixxFire explained)

[darkz]

So in the 2018 NHT VCAA exam, the first short answer question provides this information and asks:
Two students noticed bubbles forming on the submerged leaves of an Elodea plant growing in an
aquarium. The bubbles seen on the leaves were the result of a gas formed within the cells of the
leaves. The photograph below shows the appearance of these bubbles.
There was a bright light shining on the aquarium. The bright light was not affecting the temperature
of the water.
a. Describe what occurs within the cells of the leaves to result in the formation of these bubbles. (3 marks)

In my answer I talked about how it could be oxygen from photosynthesis or carbon dioxide from cellular respiration, however in the answers, it says:
Chlorophyll absorbs light energy, water is split to form hydrogen ions or oxygen gas, and oxygen
will diffuse out through the plasma membrane.

Is cellular respiration not also a potential cause of these bubbles?

I'm pretty sure that this is actually because carbon dioxide dissolves into the water to form carbonic acid once it is released, hence the bubbles cannot be attributed to carbon dioxide

[starby]

could someone please give me some examples of biological, social and ethical implications

also what is the best way to use reading time?

[PhoenixxFire]

I'm pretty sure that this is actually because carbon dioxide dissolves into the water to form carbonic acid once it is released, hence the bubbles cannot be attributed to carbon dioxide

Now that’s something I should have realised given I’m doing Enviro science 😂 I don’t think they’d expect you to know that for bio though.