VCE Biology Question Thread

[kimmytaaa]

Hi guys
just wondering has anyone heard of a tutor name michael deland? if anyone has had him for biology?
And how do you create your own post?

[~V]

Hi guys
just wondering has anyone heard of a tutor name michael deland? if anyone has had him for biology?
And how do you create your own post?

New thread? Go to the board you want it to appear in, eg. Biology, then click on the button [NEW TOPIC] on the top right just under the ad.

[Sine]

Hi AN

I've got a week to go before my first Biology SAC on movement across the membrane and would like to know what to do for revision to be fully prepared.

[Yacoubb]

Hi AN

I've got a week to go before my first Biology SAC on movement across the membrane and would like to know what to do for revision to be fully prepared.

Hey Sine,

The best way to prepare for a SAC is to practice the two main elements that will be assessed in your work: theory and practical. For theory, I'd go over all your information regarding movement across the cell membrane, the actual cell membrane structure, etc. For the practical element, think of how you could actually explain your results in relation to the theory you've studied.

Hope that's helpful

[Reus]

Hi AN

I've got a week to go before my first Biology SAC on movement across the membrane and would like to know what to do for revision to be fully prepared.

Do the checkpoints questions for that AoS

[katiesaliba]

Hi AN

I've got a week to go before my first Biology SAC on movement across the membrane and would like to know what to do for revision to be fully prepared.

Go on Youtube and search similar experiments! It'll help you comprehend your own results. Also, as aforementioned, revise equilibrium, osmosis, diffusion, phospholipid bilayer structure, etc. Just know the concepts and you'll be fine! 

[cosine]

Go on Youtube and search similar experiments! It'll help you comprehend your own results. Also, as aforementioned, revise equilibrium, osmosis, diffusion, phospholipid bilayer structure, etc. Just know the concepts and you'll be fine! 

My teacher said osmosis typically does not reach equilibrium?

For example, when pure distilled water is separated by a semi-permeable membrane, with a sucrose solution on the other side. She said the the distilled water will eventually diffuse into the sucrose solution through the membrane, but some water will always remain as it is. So my question is, to reach equilibrium doesn't the sucrose solution absorb ALL the water from the other side of the beaker? Because the distilled water has no solute concentration, so it will keep dilluting the sucrose solution until there is no more water left... Is this theory wrong? It seems logical, and after telling my teacher this, she just came with a conclusion that osmosis never reaches equilibrium, which is false -.-

Thanks in advance,

[vox nihili]

My teacher said osmosis typically does not reach equilibrium?

For example, when pure distilled water is separated by a semi-permeable membrane, with a sucrose solution on the other side. She said the the distilled water will eventually diffuse into the sucrose solution through the membrane, but some water will always remain as it is. So my question is, to reach equilibrium doesn't the sucrose solution absorb ALL the water from the other side of the beaker? Because the distilled water has no solute concentration, so it will keep dilluting the sucrose solution until there is no more water left... Is this theory wrong? It seems logical, and after telling my teacher this, she just came with a conclusion that osmosis never reaches equilibrium, which is false -.-

Thanks in advance,

In this case it won't completely go to equilibrium, no. That's because gravity counteracts osmotic pressure. SO even though the water wants to move in, gravity will stop some of it from doing so.

[cosine]

In this case it won't completely go to equilibrium, no. That's because gravity counteracts osmotic pressure. SO even though the water wants to move in, gravity will stop some of it from doing so.

Alright, thank you!

But osmosis typically stops at equilibrium, like diffusion, right? Thanks

[vox nihili]

Alright, thank you!

But osmosis typically stops at equilibrium, like diffusion, right? Thanks

Yes absolutely. You're actually best to assume that it always goes to equilibrium. You certainly wouldn't be expected to know anything about what we've just discussed.

[Sine]

Hey Sine,

The best way to prepare for a SAC is to practice the two main elements that will be assessed in your work: theory and practical. For theory, I'd go over all your information regarding movement across the cell membrane, the actual cell membrane structure, etc. For the practical element, think of how you could actually explain your results in relation to the theory you've studied.

Hope that's helpful

Do the checkpoints questions for that AoS

Go on Youtube and search similar experiments! It'll help you comprehend your own results. Also, as aforementioned, revise equilibrium, osmosis, diffusion, phospholipid bilayer structure, etc. Just know the concepts and you'll be fine! 

Thanks for the advice.

What are some typical questions which usually appear in this SAC?

[Yacoubb]

Thanks for the advice.

What are some typical questions which usually appear in this SAC?

- Drawing the structure of the plasma membrane (phospholipid bi-layer aggregation, protein channels, etc).
- Indicating the functions of the various elements of the membrane.
- Mentioning what happens to a cell when placed in X solution (it being hyper/hypo/isotonic) and the reason why (i.e. discussing in relation to osmosis).

^ those are likely questions that will be asked on the SAC. Good luck!

[cosine]

I have a question regarding plasma membranes:

Are protein channels the same as carrier proteins? I know they have different structures, but why do many people refer to them as the same thing? Also does active transport only occur via carrier proteins?

Thanks in advance

[vox nihili]

I have a question regarding plasma membranes:

Are protein channels the same as carrier proteins? I know they have different structures, but why do many people refer to them as the same thing? Also does active transport only occur via carrier proteins?

Thanks in advance

No they're not the same. They're fundamentally different in structure. To transport things across the membrane, channel proteins don't have to change shape, whereas carrier proteins do.
Active transport is only done by carrier proteins. There are a few cases where this is not actually the case, but for the purposes of VCE it's better to assume that it always occurs via carrier proteins.

[cosine]

No they're not the same. They're fundamentally different in structure. To transport things across the membrane, channel proteins don't have to change shape, whereas carrier proteins do.
Active transport is only done by carrier proteins. There are a few cases where this is not actually the case, but for the purposes of VCE it's better to assume that it always occurs via carrier proteins.

Thank you Mr. T-Rav!!

So, when it says list two proccesses that cannot occur if protein channels were not present in the plasma membrane:

Facilitated diffusion via protein channels cannot occur, but what would be the second process?