VCE Biology Question Thread

[nerdmmb]

That's what I thought...then I remembered that it was meant to relate to our starch/amylase experiment somehow (which I payed no attention to), but it's still a slightly vague question IMO

yeah it is quite strange but just going to take a guess -- There should be no difference because amino-acids are universal so amylase in both fungi and humans should be the same - their structure, function, etc.

But I may be wrong --> http://www.wisegeek.com/what-is-an-amylase-protein.htm

^Check out this article, it's quite helpful

[vox nihili]

If there is more information given, such as in a SAC/experiment, then that's a perfectly reasonable question. It's just not something you should know off the top of your head.

[RazzMeTazz]

If you get one average sac mark, does that affect your whole study score? :/

[MM1]

If you get one average sac mark, does that affect your whole study score? :/

Not really. Don't be deterred by your SAC marks. Just try to do well on the exam.

[millie96]

In a hypertonic solution- as there is a higher concentration of solutes outside the cell relative to inside, does this mean that there is a higher concentration of h20 within the cell compared to outside? Is this why osmosis occurs and the cells lose mass in a hypertonic solution?

[alchemy]

In a hypertonic solution- as there is a higher concentration of solutes outside the cell relative to inside, does this mean that there is a higher concentration of h20 within the cell compared to outside? Is this why osmosis occurs and the cells lose mass in a hypertonic solution?

Yes.

[nhmn0301]

If I place plant cell in a very high alcohol concentration solution, then alcohol will diffuse into the cell. Hence, will cause the cell to burst ? Even though I know that plant have cell wall, but is there any chances where the pressure inside is too high and the cell burst out, releasing its content?
Thanks guys!

[Sup]

If I place plant cell in a very high alcohol concentration solution, then alcohol will diffuse into the cell. Hence, will cause the cell to burst ? Even though I know that plant have cell wall, but is there any chances where the pressure inside is too high and the cell burst out, releasing its content?
Thanks guys!

Wouldn't water move out of the plant cell via osmosis (because the plant cell is hypotonic to the alcohol solution) causing the plant cell to shrink?

[alchemy]

If I place plant cell in a very high alcohol concentration solution, then alcohol will diffuse into the cell. Hence, will cause the cell to burst ? Even though I know that plant have cell wall, but is there any chances where the pressure inside is too high and the cell burst out, releasing its content?
Thanks guys!

Net movement of water will be to outside the cell to begin with. Remember, the plant cell wants to maintain an Isotonic environment, hence the reason for water to move out. Some solute particles will move in but, there will never be too much moving in as once the concentration gradient is equal there will be no net movement of water or solute into or out of the cell.

[nhmn0301]

Net movement of water will be to outside the cell to begin with. Remember, the plant cell wants to maintain an Isotonic environment, hence the reason for water to move out. Some solute particles will move in but, there will never be too much moving in as once the concentration gradient is equal there will be no net movement of water or solute into or out of the cell.

Wouldn't water move out of the plant cell via osmosis (because the plant cell is hypotonic to the alcohol solution) causing the plant cell to shrink?

Thanks guys. I'm a bit confused when placing plant cell inside the alcohol solution. For instance, my experiment is to place a beetroot cell inside different alcohol concentration solutions. I observe that the more concentrated the alcohol, the more pink pigment from beetroot moves out of the cell. So just repeating what you guys have mentioned, "there will be a net movement of alcohol into the cell through simple diffusion due to the lipid nature of alcohol, however, there will also be a net movement of pink pigment (anthocyanin) from the beetroot cell out side of the cell to balance the concentration gradient. Consequently, the more concentrated the alcohol solution, the more anthocyanin moves out of the cell, generating an equilibrium state." Is this explanation right?

Also, when I write down the word "hypertonic solution" to refer to the alcohol environment, by teacher said it wasn't right since this is not talking about the amount of solute, she just wants me to refer to it as "a high concentration of alcohol solution", but somehow, this still doesn't make sense to me. Is she right? Can anyone give me a  more detailed explanation?
Thanks so much !

[vox nihili]

Also, when I write down the word "hypertonic solution" to refer to the alcohol environment, by teacher said it wasn't right since this is not talking about the amount of solute, she just wants me to refer to it as "a high concentration of alcohol solution", but somehow, this still doesn't make sense to me. Is she right? Can anyone give me a  more detailed explanation?
Thanks so much !

If the solution is not pure alcohol, alcohol is the solute and your teacher is wrong. However, it's also important to remember that alcohol can go straight through the membrane and will diffuse pretty quickly.

[rhinwarr]

Situation:
Protein solution is placed in a cellulose membrane and submerged in a beaker full of alkaline solution.

What would be expected to happen? I think water and salt from the alkaline solution would enter the membrane, but what would go out? Would it be right in saying nothing goes out or should I say that water and salt goes out of the membrane (since particles move in both directions but the net movement is into the membrane?)

[Frozone]

Hey guys I am stumped on this question.
In eukaryotic cells the conversion of adp and phosphate into ATP occurs:.....

I put my answer as "in both the mitochondria and the cytoplasm, and releases energy" since cellular respiration involves a catabolic reaction.
But the answer is "in both the mitochondria and the cytoplasm, and requires energy".
Why is this so? I have a hunch  that it's because energy is needed to convert adp and phosphate into ATP but I'm not sure. 

[vox nihili]

yeah it is quite strange but just going to take a guess -- There should be no difference because amino-acids are universal so amylase in both fungi and humans should be the same - their structure, function, etc.

But I may be wrong --> http://www.wisegeek.com/what-is-an-amylase-protein.htm

^Check out this article, it's quite helpful

There are normally small differences between the primary structures of human and fungal proteins. There was an exam question a few years ago that compared cow, horse, human and pig insulin and the differences can actually be quite large, meaning that the protein tends to operate a little differently under different temperatures.

[Jason12]

for hypotonic solutions my revision sheet says "remember to say compared to the cytosol the solution is hypotonic. How is cytosol involved in hypertonic/hypotonic solutions.?