VCE Biology Question Thread

[MM1]

Just wondering which topic everyones school is up to?

[Rishi97]

Just wondering which topic everyones school is up to?

Our school is doing ezymes atm but we have a sac on osmosis on tuesday.

[Rishi97]

Has anyone done the osmosis prac on potatoes?
If yes, what were some of the questions asked? I have my sac on tuesday and I want to cover EVERYTHING!!!

[nerdmmb]

Has anyone done the osmosis prac on potatoes?
If yes, what were some of the questions asked? I have my sac on tuesday and I want to cover EVERYTHING!!!

Yes
It was actually quite fun, although we've only done part 1 which is the experiment.

I think just try and link how everything is related to eachother - a mind map might be helpful!

[nerdmmb]

This is what one looks like (only a very recent discovery, and actually earned them a nobel prize!)

(Image removed from quote.)

Would it be correct to say that ribosomes were synthesised by other ribosomes?

[vox nihili]

Would it be correct to say that ribosomes were synthesised by other ribosomes?

No, not entirely. The protein component yes, the rRNA component no. The rRNA comes straight from RNA pol.

[alchemy]

Has anyone done the osmosis prac on potatoes?
If yes, what were some of the questions asked? I have my sac on tuesday and I want to cover EVERYTHING!!!

You need to cover the main things but perhaps not everything; there are still things on membranes that scientists don't yet know (as with almost anything else)...
I had my SAC 2 weeks ago and I would advise you to read the questions carefully and respond using important key words that you've been taught to use. This doesn't mean pick fancy wording you found on the internet, as teachers hate that. Also, don't paraphrase many of the answers here on AN as we try to explain what we can in the most detail so you comprehend the entirety of the biological concepts, whereas in SAC's there's probably not enough time for that.
There's really not much content on the 'Movement across Membranes' topic in VCE, so just make sure your wording is precise and succinct. Working on timing will surely help as well C: Good Luck!

[alchemy]

Just wondering which topic everyones school is up to?

Biomacromolecules

[MM1]

Biomacromolecules

LOL, that's a joke right. haha

[Rishi97]

You need to cover the main things but perhaps not everything; there are still things on membranes that scientists don't yet know (as with almost anything else)...
I had my SAC 2 weeks ago and I would advise you to read the questions carefully and respond using important key words that you've been taught to use. This doesn't mean pick fancy wording you found on the internet, as teachers hate that. Also, don't paraphrase many of the answers here on AN as we try to explain what we can in the most detail so you comprehend the entirety of the biological concepts, whereas in SAC's there's probably not enough time for that.
There's really not much content on the 'Movement across Membranes' topic in VCE, so just make sure your wording is precise and succinct. Working on timing will surely help as well C: Good Luck!

Thanks heaps Alchemy... Yeah, there's not much to remember so I'm trying to make my answers make sense atm. Lol, I have a little problem of rambling on sometimes. haha

[vox nihili]

Has anyone done the osmosis prac on potatoes?
If yes, what were some of the questions asked? I have my sac on tuesday and I want to cover EVERYTHING!!!

You'll need to be able to relate changes in the potato cells with the nature of the cellular and external fluid, and explain that in terms of osmosis. That's pretty much what that prac is going to be about. Being able to describe under what circumstances osmosis will occur and also explain why it will occur. The same will go with diffusion, you must be able to relate that to the concentrations externally and internally, as well as to osmosis—why will diffusion occur in some circumstances, and osmosis in others?

Lastly, I expect that you'll need to make some sort of comment on turgour pressure. You may be asked to comment on why lysis doesn't occur. 

[alchemy]

LOL, that's a joke right. haha

Unfortunately, it isn't. I would've expected most schools to be up to here by now but, our school started early during orientation and it's such that our pace is considerably slower than expected.

EDIT: 500'th post D: I really need to get a life...

[nerdmmb]

You'll need to be able to relate changes in the potato cells with the nature of the cellular and external fluid, and explain that in terms of osmosis. That's pretty much what that prac is going to be about. Being able to describe under what circumstances osmosis will occur and also explain why it will occur. The same will go with diffusion, you must be able to relate that to the concentrations externally and internally, as well as to osmosis—why will diffusion occur in some circumstances, and osmosis in others?

Lastly, I expect that you'll need to make some sort of comment on turgour pressure. You may be asked to comment on why lysis doesn't occur.

I'm going to attempt this question, could someone please correct me if I'm wrong?

Lysis doesn't occur as the plant cells are encapsulated in a cell wall which makes them turgor and prevents the cell from rupturing.

If we were asked as to why lysis doesn't occur in a salt solution that is hypertonic to the potato slices, would it also be correct to say that there was a net movement of water molecules from the potato tuber cells via osmosis therefore the cells shrunk-this was evidenced by the significant decrease in mass.
And can we say that lysis doesn't occur since it's a plant cell? Instead, plasmolysis occurs?

[MM1]

Unfortunately, it isn't. I would've expected most schools to be up to here by now but, our school started early during orientation and it's such that our pace is considerably slower than expected.

EDIT: 500'th post D: I really need to get a life...

Idk if trolling but okay good luck

[vox nihili]

I'm going to attempt this question, could someone please correct me if I'm wrong?

Lysis doesn't occur as the plant cells are encapsulated in a cell wall which makes them turgor and prevents the cell from rupturing.

If we were asked as to why lysis doesn't occur in a salt solution that is hypertonic to the potato slices, would it also be correct to say that there was a net movement of water molecules from the potato tuber cells via osmosis therefore the cells shrunk-this was evidenced by the significant decrease in mass.

Yeah that's essentially right, except turgour can't be made, it is a quality of the cell. Plant cells don't undergo plasmolysis in hypotonic solutions because of the effect of the cell wall, which prevents the membrane from breaking and limits the amount of water that can move into the cell. The plant cell is said to be turgid when osmosis ceases despite there being a clear concentration gradient between the cellular fluid and the external fluid.

Well lysis doesn't occur in salt because, as you pointed out, it's hypertonic so the water moves out.

Unfortunately, it isn't. I would've expected most schools to be up to here by now but, our school started early during orientation and it's such that our pace is considerably slower than expected.

EDIT: 500'th post D: I really need to get a life...

We finished our course a day before the exam, don't worry mate