VCE Biology Question Thread

[bts]

two questions please:
1) A DNA strand: ATGCGTACTT write the sequence of bases in the RNA copy
is it: UACGCAUGAA?

2) When egg white is heated this liquid becomes white opaque solid, explain observation with knowledge of protein structure.
is it: proteins have specific narrow ranges in which they operate, any deviance from this range (e.g. when the protein is heated it is no longer working at temperature it usually does) this causes the proteins to be denatured and as the egg white cools down the proteins coagulate and turns into the white solid?

P.S would we ever be asked about how the structure of the protein is related to its function?

[cosine]

Guys, to get a 50 in Biology (sounds absurd but im going for it), what sac grades am i looking at? My first sac is next week, and im shaking.. :3

[Cogglesnatch Cuttlefish]

Guys, to get a 50 in Biology (sounds absurd but im going for it), what sac grades am i looking at? My first sac is next week, and im shaking.. :3

Honestly your ranking is much more important than your actual grades. If you perform really well on the exam, your grades will get scaled up accordingly

[vanessa14]

Anyone help ? Quick question about the Biozone?

[vceva]

Hi guys!

Ridiculously easy question... what would be a good/concise definition for diffusion, osmosis and active transport?
Does anyone have a definition given by VCAA from past exams?


Thanks

[alondouek]

Hi guys!

Ridiculously easy question... what would be a good/concise definition for diffusion, osmosis and active transport?
Does anyone have a definition given by VCAA from past exams?


Thanks

Diffusion: The passive net movement (down a concentration gradient) of a solute from a region of high solute concentration to a region of low solute concentration.

Osmosis: Passive net transport (again, down a concentration gradient) of a solvent (almost always water for the purposes of VCE biology) from a region of low solute concentration to a region of high solute concentration. This process usually takes place across a semi-permeable membrane.

Active transport: Active (therefore requiring energy as ATP) net transport of a solute from a region of low solute concentration to a region of high solute concentration (therefore up a concentration gradient).





I've colour-coded some important bits of those definitions, because students often get confused between solvents/solutes and the like

"Net" is highlighted as such as it is important to remember that solutions are NOT static; there is constant flow between regions. Hence, we can identify changes only as NET movements of solutes relative to solvent concentrations in regions of a solution.

Hope this helps!

[kimmytaaa]

Does anyone know what is the theory of enzymes?

[Rishi97]

Does anyone know what is the theory of enzymes?

I think the theory may be referring to the 2 models : Induced fit and Lock and Key model.... could someone please confirm

[Reus]

I think the theory may be referring to the 2 models : Induced fit and Lock and Key model.... could someone please confirm

Yeah sounds like it.

[heids]

Guys, to get a 50 in Biology (sounds absurd but im going for it), what sac grades am i looking at? My first sac is next week, and im shaking.. :3

Don't worry about the 'sounds absurd' - it's great to have such an aim and someone has to get it !
Bear in mind that for Bio, SACs for the whole year make up only 40%, and there are about 10 SACs from memory - they are each worth very little.  The point is, simply do your best on each SAC.  Try to get as close to 100% as you can (though that's in no way essential for a 50 in Bio - remember the importance of cohort ranking) but don't stress if you miss it.  Just work harder next time!

[Individu]

What is the VCE definition of chromosome?

[warya]

Question: Explain how the conversion of Carbon dioxide to bicarbonate ions in red blood cells assists in the removal of carbon dioxide from red blood cells

Teacher's answer: Continual change of Carbon dioxide to bicarbonate ions that can easily leave red blood cell

But shouldn't it be harder for ions to pass through membranes as they are charged and don't mix well with lipids, whilst CO2 is small and can pass in between the phospholipid molecules?

I'm not sure I understand the question and I have the SAC tomorrow morn, can anyone help?

[vox nihili]

Question: Explain how the conversion of Carbon dioxide to bicarbonate ions in red blood cells assists in the removal of carbon dioxide from red blood cells

Teacher's answer: Continual change of Carbon dioxide to bicarbonate ions that can easily leave red blood cell

But shouldn't it be harder for ions to pass through membranes as they are charged and don't mix well with lipids, whilst CO2 is small and can pass in between the phospholipid molecules?

I'm not sure I understand the question and I have the SAC tomorrow morn, can anyone help?

Yeah annoying question. There's a transporter for bicarbonate ions, so that's why it can move through the membrane pretty easily. The reason that conversion to bicarbonate helps facilitate transport of carbon dioxide in the blood is that carbon dioxide is relatively insoluble, meaning that the blood can only carry a tiny bit of it. Bicarb, on the other hand, is highly soluble so the blood can take a lot.

[warya]

That would be a pretty difficult question to answer for someone who isn't taking chem, yah very annoying, they shouldve specified there was a transporter or something

Thank you

[alondouek]

That would be a pretty difficult question to answer for someone who isn't taking chem, yah very annoying, they shouldve specified there was a transporter or something

Thank you

Well, the make-up of the phospholipid bilayer and embedded transport proteins is something you need to know! It's good that you recognised that ions are unable to pass through the bilayer itself (so you've pretty much arrived at the solution), but the next thing you need to do is take that inference a step further and consider in what ways can these ions pass between the internal and external cellular environments?

As above, an ion transporter is needed to complete this action as passive diffusion across the cell membrane is not viable.

Extra credit: Another example (and a biologically critically important one at that) of cellular ion transport is the exchange of sodium and potassium ions between environments in neuronal axonal transmission of information.