VCE Biology Question Thread

[Reus]

I've been to some lectures and I have a tutor...they both clarified that we need to know it.

My lecturer said not to worry about it. (not that hard to know anyways but just saying)

Haven't you done 1/2 physics Reus? :p
It's not explicitly mentioned, but it may fall under radiometric dating and  whatnot.

Yes I did! I also dropped physics, which was the pinnacle of my life

Is it sufficient to define the secondary structure of proteins as: Local 3-dimensional folding resulting in alpha helices and beta pleated sheets and the tertiary structure as: Overall 3-dimensional folding composed of secondary structures?

You might want to include random coiling and disulphide bridges (tertiary)

[katiesaliba]

Is it sufficient to define the secondary structure of proteins as: Local 3-dimensional folding resulting in alpha helices and beta pleated sheets and the tertiary structure as: Overall 3-dimensional folding composed of secondary structures?

I'd also include for the tertiary structure that the bonds occur due to R-group interactions.

[anat0my]

Why are hormones required in small concentrations? What would happen if they were in large conc.? Thanks! 

[chekside]

I'd also include for the tertiary structure that the bonds occur due to R-group interactions.

Ok thanks 

[Reus]

Why are hormones required in small concentrations? What would happen if they were in large conc.? Thanks! 

Negative feedback loop?

[katiesaliba]

In fact, one past paper merely mentioned that immune cells "have receptors which can distinguish between differs types of protein markers of cells, and thus distinguish  between self and non self" or something along those lines.
It didn't require you to mention "MHC" (I think it was bracketed).

The assessment report says 'to distinguish the different kinds of (MHC) on all cells', so it would have to be MHC really even though it's bracketed. I think saying protein markers would be too simplistic IMO, considering that we explicitly learn about MHC.

[Reus]

The assessment report says 'to distinguish the different kinds of (MHC) on all cells', so it would have to be MHC really even though it's bracketed. I think saying protein markers would be too simplistic IMO, considering that we explicitly learn about MHC.

Is it just that all nucleated cells have MHC 1 markers whereas B cells, macrophages and dendritic cells additionally contain MHC 2 markers?

[katiesaliba]

Is it just that all nucleated cells have MHC 1 markers whereas B cells, macrophages and dendritic cells additionally contain MHC 2 markers?

Yep, but the assessment report was so vague and didn't even specify the class of MHC markers 

[grannysmith]

The assessment report says 'to distinguish the different kinds of (MHC) on all cells', so it would have to be MHC really even though it's bracketed. I think saying protein markers would be too simplistic IMO, considering that we explicitly learn about MHC.

Fair enough, but it's somewhat confusing that a) RBCs dont have MHC and b) this doesn't take into account acellular components of the body (protein molecules and the like).

Unless the question asked for how immune cells distinguish between non/self CELLS specifically?

That's why I was leaning towards 'protein markers' cos it's more general. Then again, what VCAA says goes.

[shivaji]

Fair enough, but it's somewhat confusing that a) RBCs dont have MHC and b) this doesn't take into account acellular components of the body (protein molecules and the like).

Unless the question asked for how immune cells distinguish between non/self CELLS specifically?

That's why I was leaning towards 'protein markers' cos it's more general. Then again, what VCAA says goes.

But MHC markers aren't the only markers which are used in cellular recognition. Aren't glycoproteins, glycolipids eetc. which are not MHC markers involved as well?

[shivaji]

Is this a good way to describe Mendel's law of Segregation:

That any allele from a pair can enter any gamete?

[katiesaliba]

Fair enough, but it's somewhat confusing that a) RBCs dont have MHC and b) this doesn't take into account acellular components of the body (protein molecules and the like).

Unless the question asked for how immune cells distinguish between non/self CELLS specifically?

That's why I was leaning towards 'protein markers' cos it's more general. Then again, what VCAA says goes.

I know right :|

Oh gosh, the question itself was 'Explain how cells of the immune system determine self from non-self molecules'

[Damo23]

Hey do any of you guys know:
How to describe what happens when the impulse generated along a motor neuron reaches a muscle fiver resulting in it's contraction? I'm not sure but I said this has got to do with neurotransmitter being broken down.
Why inhibitory neurons necessary for functioning of the nervous system? Idk but has this got to do with feeling no pain?
How inhibitory neurons prevent excitation of the next neuron? Do they like produce inhibitory neurotransmitter that block receptors so like competitive enzymes?

Are lipids made from condensation polymersairion?

After the synthesis stage in mitosis does dna have 92 molecules of dna or 92 chromosomes?

What are benefits if signal transduction? I know about amplification is there any others?

In signal transduction, the original signalling molecule does not pass along the pathway but rather is changed into a different form? Give an example,  I have no clue about this question 

Yeh anyone who knows answers to these Q's could they let me know 

[vox nihili]

Would it hurt if you added this information (not the roles) if a question asked for the steps of protein synthesis? Or is it just a waste of time? Thanks.

I'd avoid it. You need to know that the modifications happen, but you'd be wasting your time explaining why they occur.

[katiesaliba]

Hey do any of you guys know:
How to describe what happens when the impulse generated along a motor neuron reaches a muscle fiver resulting in it's contraction? I'm not sure but I said this has got to do with neurotransmitter being broken down.
Why inhibitory neurons necessary for functioning of the nervous system? Idk but has this got to do with feeling no pain?
How inhibitory neurons prevent excitation of the next neuron? Do they like produce inhibitory neurotransmitter that block receptors so like competitive enzymes?

Are lipids made from condensation polymersairion?

After the synthesis stage in mitosis does dna have 92 molecules of dna or 92 chromosomes?

What are benefits if signal transduction? I know about amplification is there any others?

In signal transduction, the original signalling molecule does not pass along the pathway but rather is changed into a different form? Give an example,  I have no clue about this question 

Yeh anyone who knows answers to these Q's could they let me know 

How to describe what happens when the impulse generated along a motor neuron reaches a muscle fiver resulting in it's contraction?
This is about neuromuscular junctions. Neurotransmitter diffuses across the synapse between the pre-synaptic neuron and muscle fibre, and binds to muscle cell receptors, which promotes an intracellular response eventually resulting in the contraction of the muscle.

Why inhibitory neurons necessary for functioning of the nervous system? Idk but has this got to do with feeling no pain?
Inhibitory neurons ensure that cells respond to only the most potent stimuli.
 
How inhibitory neurons prevent excitation of the next neuron? Do they like produce inhibitory neurotransmitter that block receptors so like competitive enzymes?
I don't think we need to know this (not explained in NOB in detail...however the textbook has some really nice visuals! Pg. 178)

Are lipids made from condensation polymersairion?

NO! lipids are not polymers because they have no monomer (fatty acids and glycerol are building blocks, not monomers). Lipids are formed via condensation reactions, however they don't polymerise. 

After the synthesis stage in mitosis does dna have 92 molecules of dna or 92 chromosomes?

What do you mean by synthesis stage in mitosis? Do you mean DNA replication in the cell cycle? Because if so, then 46 chromosomes that have two sister chromatids. (# of chromosomes is relative to the # of centromeres in a cell)

What are benefits if signal transduction? I know about amplification is there any others?
It's how a cell responds to any extracellular message. VITAL in homeostasis, among many other important processes.

In signal transduction, the original signalling molecule does not pass along the pathway but rather is changed into a different form? Give an example.
This is a question about hydophilic ligands/signalling molecules. So secondary messengers are used. An example would be the signal transduction of glycagon.