VCE Biology Question Thread

[Gogo14]

Hey, just a heads up, you misspelt exergonic as exogonic and endergonic as endogonic

Exergonic reaction: Releases energy. Example: cellular respiration.
Endergonic reaction: Takes in energy. Example: Photosynthesis.
Catabolic reaction: All catabolic reactions are also exergonic. Means that something is being broken down. (Big pieces into smaller pieces)
Anabolic reaction: All anabolic reactions are also endergonic. The same as an endergonic reaction. Means that something is being built up. (Small pieces into a large piece)

Don't know about exothermic, endothermic and metabolic reactions, sorry!

Wait, but does that mean that all reactions are endergonic because they require an activation energy, hence taking in energy?

[TheAspiringDoc]

Wait, but does that mean that all reactions are endergonic because they require an activation energy, hence taking in energy?

Nononono, although you could technically call part of a bodily exergonic reaction endergonic due to its need for the activation energy, it's really just about the net (total) energy that is taken in/given out

[sunshine98]

Wait, but does that mean that all reactions are endergonic because they require an activation energy, hence taking in energy?

No(but you are right about activation energy). But it gets kinda chemistry-like if we delve into this (in chem, all reactions will need energy to begin- that is , the activation energy- and all reactions release energy) . But basically , its more so about a 'net intake of energy ' (the energy taken in is greater than that released) and 'net release of energy' (energy released is greater than that taken in).
This is stuff you don't need to know about in VCE bio

[TheAspiringDoc]

Are all polar molecules hydrophilic, and are all non-polar molecules hydrophobic? (Can the two words be used interchangably?)

What is the difference between a charged molecule, a non-charged molecule and a polar molecule, in regards to how they enter a cell?

Can a charged molecule be non-polar?

for the first question, remember that amphipathic molecules are partly polar and partly non-polar.
Otherwise yeah, I think they're interchangeable.

Q2) nobody really says 'non-charged' - instead you talk about the polarity if it's not charged. Keep in mind that size also plays a role, but if a molecule is polar then it generally has to pass through by facillitated diffusion. I'm not sure about charged particles (as you sad, do they have to be polar? )

[sunshine98]

Are all polar molecules hydrophilic, and are all non-polar molecules hydrophobic? (Can the two words be used interchangably?)

Yes. Because a molecule is polar , it is hydrophilic. Because a molecule is non polar it is hydrophobic. Polarity has to do with structure of the molecule. And hydrophilic-ness or phobic-ness comes from the way that molecule would interact with water. And because we abide by the rule 'like dissolves like' (which is an oversimplification of a chem concept) , and because water is polar anything that is polar is hydrophilic. So basically , yes , in bio we can use these words interchangeably.

What is the difference between a charged molecule, a non-charged molecule and a polar molecule, in regards to how they enter a cell?

Charged and polar will undergo facilitated diffusion
Non charged and non polar will undergo simple diffusion
This is given that size is not an affecting factor and we're going along the concentration gradient.

Can a charged molecule be non-polar?

Charge and polarity are two different things . But in bio , and in regards to the way things travel through the membrane , always think of polar and charged together and non polar and non charged together.
EDIT: oooh well ninja'd again 

[vox nihili]

Ah, thanks! Could you detail what the actual process is?

BEYOND VCE

Very, very basically.


Repair Mechanisms

Enzymes in the nucleus detect mutations. Most of the time they will respond to these mutations and prevent them from being inherited. On the very rare occasions these processes fail, the mutation becomes embedded in the DNA and is therefore heritable.

Cancer

The cell cycle—something you should know about in VCE Biology—basically describes the progression of cells from a newly-formed cell to a dividing cell. Genes control the progression of cells through this cycle. Some genes prompt the progression through the cycle, others slow it down. To use an analogy, some genes act as the accelerators, promoting growth and division, others act as the brakes.

Cancer occurs when mutations (see above) disrupt the balance between the accelerator genes (called proto-oncogenes) and the brake genes (called tumour suppressor genes [TSGs]). These mutations make the proto-oncogenes (once mutated called oncogenes) more active, and the TSGs less active, or not active at all.

In most cases, mutations will actually affect the machinery that prevent mutation (explained above). This therefore accelerates the accrual of mutations in the genome; consequently making it more likely that mutations will take place in proto-oncogenes/TSGs

[TheAspiringDoc]

both TSGs have to be mutated, but only one of the Proto-onc's need to be, yeah?

[vox nihili]

both TSGs have to be mutated, but only one of the Proto-onc's need to be, yeah?

In a simple world, yes. There are some notable exceptions though

[geminii]

Hey everyone, I'm having trouble with a few multiple choice questions. I'll post one now and then post the others later to give people a chance to answer.

The three-dimensional structure of a protein
A. is determined by its sequence of amino acids
B. varies depending on the interaction of the protein molecule with other molecules
C. is irrelevant to the function of the protein molecule
D. is determined by the active site

I'm torn between A and B but leaning more towards A, so any help would be much appreciated! Thanks

[TheAspiringDoc]

Hey everyone, I'm having trouble with a few multiple choice questions. I'll post one now and then post the others later to give people a chance to answer.

The three-dimensional structure of a protein
A. is determined by its sequence of amino acids
B. varies depending on the interaction of the protein molecule with other molecules
C. is irrelevant to the function of the protein molecule
D. is determined by the active site

I'm torn between A and B but leaning more towards A, so any help would be much appreciated! Thanks

although B does look kinda sensible, A is pretty promising. As wiki says "The interactions and bonds of side chains within a particular protein determine its tertiary structure."

EDIT: lol I just realised, your profile has a link to the biol vid that my profile used to have a link to and is my profile pic?

[Sine]

Hey everyone, I'm having trouble with a few multiple choice questions. I'll post one now and then post the others later to give people a chance to answer.

The three-dimensional structure of a protein
A. is determined by its sequence of amino acids
B. varies depending on the interaction of the protein molecule with other molecules
C. is irrelevant to the function of the protein molecule
D. is determined by the active site

I'm torn between A and B but leaning more towards A, so any help would be much appreciated! Thanks

The answer is A
B- maybe(kinda vague)
C- most important thing
D- structure determines active site

[TheAspiringDoc]

Yeah, I think Sine's onto it - B is fairly vague, espicially given that the one thing that really diversifies proteins upon synthesis is their a.a. sequence, and they all initially encounter similar organelles and molecules anyway (e.g. all from ribosomes, then ER, golgi etc.). What was your justification for B?

[vox nihili]

Hey everyone, I'm having trouble with a few multiple choice questions. I'll post one now and then post the others later to give people a chance to answer.

The three-dimensional structure of a protein
A. is determined by its sequence of amino acids
B. varies depending on the interaction of the protein molecule with other molecules
C. is irrelevant to the function of the protein molecule
D. is determined by the active site

I'm torn between A and B but leaning more towards A, so any help would be much appreciated! Thanks

A and B are both correct

[geminii]

although B does look kinda sensible, A is pretty promising. As wiki says "The interactions and bonds of side chains within a particular protein determine its tertiary structure."

Thanks!!

The answer is A
B- maybe(kinda vague)
C- most important thing
D- structure determines active site

Thanks for this! Are you saying that answers C and D are wrong? (AKA what do you mean by 'most important thing'?)

EDIT: lol I just realised, your profile has a link to the biol vid that my profile used to have a link to and is my profile pic?

Ah that's pretty cool! I didn't know it was that video that was linked on your profile, but I knew your profile pic came from it


Ok another few questions I'm not sure about...

Which of the following activities is not found in all living cells?
A. movement
B. aerobic respiration
C. growth
D. synthesis

I'm thinking B or D?...

Amino acids contain four chemical groups connected to a central carbon atom. Which of the following atoms or groups of atoms is not connected to the central carbon in all amino acids?
A. NH2
B. COOH
C. CH3
D. H

I had no idea for this one, never came across this scenario before..

Which of the following is not a function of protein molecules found in the membranes of cells?
A. They act as channels for the transport of lipid soluble molecules
B. They act as receptor sites for some signalling molecules
C. They facilitate the diffusion of charged particles
D. They are the site of active uptake of glucose molecules.

I'm thinking the answer is D? But I'm not sure.


Thanks again for all the help!!

EDIT: Just saw TheAspiringDoc's last post:

Yeah, I think Sine's onto it - B is fairly vague, espicially given that the one thing that really diversifies proteins upon synthesis is their a.a. sequence, and they all initially encounter similar organelles and molecules anyway (e.g. all from ribosomes, then ER, golgi etc.). What was your justification for B?

Well I felt that since the quaternary structure is all the molecules joining with other molecules in the form of strands of amino acids, they would be interacting with each other and that might cause the structure of the protein to be the way that it is.

[sunshine98]

Ok another few questions I'm not sure about...

Which of the following activities is not found in all living cells?
A. movement
B. aerobic respiration
C. growth
D. synthesis
I'm thinking B or D?...

A-I'm thinking A, because not all cells have flagellas which is what allows movement.
B- most cells can perform it. Aerobic respiration is dependent on oxygen not something that the cell contains
C- cell cycle is something that all cells undergo , where growth is a part of one of the stages
D- All cells synthesis things  particularly proteins , that's why prokaryotes have ribosomes.

Amino acids contain four chemical groups connected to a central carbon atom. Which of the following atoms or groups of atoms is not connected to the central carbon in all amino acids?
A. NH2
B. COOH
C. CH3
D. H

Answer is  C. If you search up an image of a typical amino acid and you will see that it has all the rest attached.

Which of the following is not a function of protein molecules found in the membranes of cells?
A. They act as channels for the transport of lipid soluble molecules
B. They act as receptor sites for some signalling molecules
C. They facilitate the diffusion of charged particles
D. They are the site of active uptake of glucose molecules.

I'm thinking the answer is D? But I'm not sure.

A is the answer because they act as channels for water soluble molecules not lipid soluble. Lipid soluble will usually diffuse through if its along the concentration gradient
Hope this helps