VCE Biology Question Thread

[datfatcat]

Wait, are marks deducted if we reference information out of the scope of VCE Biol?!

No but you need to make sure the information is correct (and relevant to the question). Furthermore, like what others mentioned, you need to actually answer the question with the knowledge under the vce course

[psyxwar]

Would it be correct/sufficient to say that cholesterol helps maintain the fluid mosaic model of the cell membrane?

that doesn't really make any sense

[grannysmith]

that doesn't really make any sense

Hmm.. I guess not. Perhaps the fluidity/rigidity of the cell membrane?

[That Other Guy]

Would it be correct/sufficient to say that cholesterol helps maintain the fluid mosaic model of the cell membrane?

What do you mean by that?
If no cholesterol is present in the membrane, the cell contents will spill out into the extracellular environment. Cholesterol maintains the cell membrane's rigidity, enables it to be fluid and minimises permeability to water-soluble molecules.

[vox nihili]

Hmm.. I guess not. Perhaps the fluidity/rigidity of the cell membrane?

Fluidity.

EDIT: see what Alon says below

[Yacoubb]

Would it be correct/sufficient to say that cholesterol helps maintain the fluid mosaic model of the cell membrane?

Essentially, cholesterol's role in the cell membrane is to maintain fluidity and flexibility of the cell membrane. In cold climates, cholesterol increases the fluidity of the cell membrane to hinder the solidification of the membrane, and reduces its fluidity in normal range temps to maintain the stability of the membrane.

[alondouek]

Fluidity.

Also rigidity! Membrane cholesterol is interesting as it serves both of these purposes as needed, in different environments

[MM1]

Would it be correct/sufficient to say that cholesterol helps maintain the fluid mosaic model of the cell membrane?

Cholesterol reduces membrane fluidity by reducing phospholipid movement at moderate temperatures, but it also hinders solidification at low temperatures. [from TSFX].
It's somewhat correct but I wouldn't say sufficient if you're explaining the fluid mosaic model and how cholesterol contributes to it. I think that statement wouldn't be 100% correct because what if we consider plant cells that lack cholesterol (I think)?
It's not exactly correct and it's not sufficient, but you're on the right track. Just expound on it more. Hope this helps

[nerdmmb]

Is there a disadvantage to not organising notes according to the study design?

[psyxwar]

Function of cholesterol: cholesterol makes the cell membrane more:
o   more flexible
o   more stable
o   more fluid in colder temperatures

This is according to past assessment reports.

[Stick]

Is there a disadvantage to not organising notes according to the study design?

Not necessarily.

[grannysmith]

Is this a good summary of the different levels of protein structure?

Primary- refers to the sequence of amino acids in a polypeptide
Secondary- refers to the coiling and folding of a polypeptide due to hydrogen bonds, in the form of alpha helices, beta pleated sheets and random coils
Tertiary- refers to the conformational shape of the polypeptide, which determines its function
Quaternary- refers to the overall structure of a protein as a result of a linkage of polypeptides

Is it necessary to know the various bonds which contribute to the tertiary structure etc?

[Yacoubb]

Is this a good summary of the different levels of protein structure?

Primary- refers to the sequence of amino acids in a polypeptide
Secondary- refers to the coiling and folding of a polypeptide due to hydrogen bonds, in the form of alpha helices, beta pleated sheets and random coils
Tertiary- refers to the conformational shape of the polypeptide, which determines its function
Quaternary- refers to the overall structure of a protein as a result of a linkage of polypeptides

Is it necessary to know the various bonds which contribute to the tertiary structure etc?

That's a good summary

Its actually been stated in the FAQs that you don't have to know about bonding. But I reckon you should; when a protein denatures, weak inter particle bonds (H bonds) are broken, but strong covalent peptide bonds are not, so just be wary of that.

[vox nihili]

But I reckon you should; when a protein denatures, weak inter particle bonds (H bonds) are broken, but strong covalent peptide bonds are not, so just be wary of that.

I'm going to be a real pedant here!

It's not "weak interparticle bonds" and H bonds aren't the only ones. In essence, you're correct and without Chem you'd probably never have known. And because you're doing Chem, so for your benefit here, hydrogen bonds are by no means "weak" intermolecular interactions. They're the strong intermolecular ones. They're just weaker than covalent bonds.

The bonds that are broken up denaturation are:

Hydrogen bonds, dipole-dipole interactions, ionic bonds and Van der Waal's forces.

[grannysmith]

I'm going to be a real pedant here!

It's not "weak interparticle bonds" and H bonds aren't the only ones. In essence, you're correct and without Chem you'd probably never have known. And because you're doing Chem, so for your benefit here, hydrogen bonds are by no means "weak" intermolecular interactions. They're the strong intermolecular ones. They're just weaker than covalent bonds.

The bonds that are broken up denaturation are:

Hydrogen bonds, dipole-dipole interactions, ionic bonds and Van der Waal's forces.

Would I need to know this for the purpose of VCE Biology?