Yacoubb's Bio 3+4 Questions

[Russ]

Don't be subtle. If I have a marking scheme and you're not mentioning the points on it, I can give you a half mark at best.
For example, your point for 2) is extremely vague (what does "retain memory" mean? Do cells just remember what happened?) and if I had a checklist that required you to say something about clonal expansion, I couldn't give you the full mark, even though you have (maybe) implied that it occurs.

[Yacoubb]

Don't be subtle. If I have a marking scheme and you're not mentioning the points on it, I can give you a half mark at best.
For example, your point for 2) is extremely vague (what does "retain memory" mean? Do cells just remember what happened?) and if I had a checklist that required you to say something about clonal expansion, I couldn't give you the full mark, even though you have (maybe) implied that it occurs.

Okay but my question was whether or not I needed to mention T cells when talking about vaccines? What do you suggest I write? I mean thanks for completely attacking what I wrote. I require assistance, not someone telling me how crap my answer is.

[simpak]

I would probably approach it in terms of a timeline of sorts - what is actually happening.

For instance: the vaccine is administered and B cells with a B cell receptor specific to the particular vaccine antigen administered bind the antigen and are activated.  The B cell proliferates and differentiates and some of the differentiated cells develop into long lived memory B cells that produce antibody specific to the vaccine antigen to protect against that antigen should it be re-encountered in the future.
Additionally, the vaccine antigen is taken up by antigen presenting cells that process and present this antigen on MHCI and MHCII markers.  T cells with a T cell receptor specific to the particular vaccine antigen will be activated by these antigen presenting cells.  Activated T cells will proliferate and differentiate to produce memory T cells with a TCR specific to the vaccine antigen.  These cells will be long-lived and respond to the antigen immediately should it be re-encountered.

That would probably be modified to make it better, go ahead and see what you can do with it!

Don't be mad at Russ for pointing out that your response to the question may have been too vague - he's trying to help you to think about what you would need to include to make it more specific without feeding you an answer.  You will get much more out of that than being told exactly what to say.

What I've done above is feed you an answer that might cover your points because you've asked for one but he did hint on a couple of things that I've covered in that answer that you could have thought about yourself (for instance, clonal expansion and explaining how memory is maintained - specifically the production of antibodies or the maintenance of cells that respond to that antigen in the future).  He wasn't just saying 'it is wrong' he did give some info about how he thought you could improve it, just not so transparently.

[Yacoubb]

I would probably approach it in terms of a timeline of sorts - what is actually happening.

For instance: the vaccine is administered and B cells with a B cell receptor specific to the particular vaccine antigen administered bind the antigen and are activated.  The B cell proliferates and differentiates and some of the differentiated cells develop into long lived memory B cells that produce antibody specific to the vaccine antigen to protect against that antigen should it be re-encountered in the future.
Additionally, the vaccine antigen is taken up by antigen presenting cells that process and present this antigen on MHCI and MHCII markers.  T cells with a T cell receptor specific to the particular vaccine antigen will be activated by these antigen presenting cells.  Activated T cells will proliferate and differentiate to produce memory T cells with a TCR specific to the vaccine antigen.  These cells will be long-lived and respond to the antigen immediately should it be re-encountered.

That would probably be modified to make it better, go ahead and see what you can do with it!

Don't be mad at Russ for pointing out that your response to the question may have been too vague - he's trying to help you to think about what you would need to include to make it more specific without feeding you an answer.  You will get much more out of that than being told exactly what to say.

What I've done above is feed you an answer that might cover your points because you've asked for one but he did hint on a couple of things that I've covered in that answer that you could have thought about yourself (for instance, clonal expansion and explaining how memory is maintained - specifically the production of antibodies or the maintenance of cells that respond to that antigen in the future).  He wasn't just saying 'it is wrong' he did give some info about how he thought you could improve it, just not so transparently.

Thanks simpak

[Russ]

Okay but my question was whether or not I needed to mention T cells when talking about vaccines? What do you suggest I write? I mean thanks for completely attacking what I wrote. I require assistance, not someone telling me how crap my answer is.

You're completely misinterpreting what is constructive criticism and advice, not attacking what you wrote. I have no interest in giving people perfect answers to their questions (for various reasons), unless it's a factual knowledge deficit. It's much better for you as a student to get some prompts and advice and use that instead.

Be specific when writing an answer. Mention all the key points. Don't be vague or subtle, the person reading your answer will avoid making assumptions.

[Yacoubb]

Okay but VCAA doesn't provide 8 lines for a question like this. So I'm trying to be specific, yet shorten it do a degree where I can fit all the information. I know everything Simpak mentioned; this question, however, was worth 2 marks and had 3 lines.

[Yacoubb]

Also, the sample Biology exam seems to suggest that we need to know about action potentials - the question asks to describe how the electrical signal travels across the axon of a post-synaptic neuron. I mean, would I just need to mention that an action potential travels from one node of Ranvier to the next across the myelinated axon. Could someone help me formulate a more appropriate response?

[vox nihili]

Also, the sample Biology exam seems to suggest that we need to know about action potentials - the question asks to describe how the electrical signal travels across the axon of a post-synaptic neuron. I mean, would I just need to mention that an action potential travels from one node of Ranvier to the next across the myelinated axon. Could someone help me formulate a more appropriate response?

I think it's asking what actually causes the action potential itself, to describe the action potential. It's asking how it travels across, not where it goes if you see what I mean. I'm also fairly sure that the Nodes of Ranvier aren't part of the VCE course.

[masonruc]

Calcium channels are the only thing in the course to do with electrical impulses, This is what  I would say:

During an action potential an electrical gradient from the dendrite of the neuron to its axon terminal is triggered, the gradient is caused by the opening of calcium ion channels on the neuron's membrane causing and influx of calcium ions, contributing to the continuation of the electrical gradient down the axon of the neuron, leading to an 'all or nothing response'

Would this do... or completely wrong...

[Yacoubb]

Calcium channels are the only thing in the course to do with electrical impulses, This is what  I would say:

During an action potential an electrical gradient from the dendrite of the neuron to its axon terminal is triggered, the gradient is caused by the opening of calcium ion channels on the neuron's membrane causing and influx of calcium ions, contributing to the continuation of the electrical gradient down the axon of the neuron, leading to an 'all or nothing response'

Would this do... or completely wrong...

But doesn't the influx of calcium ions trigger the exocytosis of neurotransmitter molecules? They aren't involved in anything other than trigger the release of neurotransmitters (excitatory or inhibitory) from the pre-synaptic terminal by exocytosis.

[vox nihili]

But doesn't the influx of calcium ions trigger the exocytosis of neurotransmitter molecules? They aren't involved in anything other than trigger the release of neurotransmitters (excitatory or inhibitory) from the pre-synaptic terminal by exocytosis.

You are right.

It's sodium and potassium channels that are opened that cause the action potential to make its way along the axon. Something which I think is mentioned in the course, though not in detail. The detail is quite boring and pretty fiddly to, to be honest.

[alondouek]

The detail is quite boring and pretty fiddly to, to be honest.

What?! It was easily one of the most interesting parts of the previous study design (and of uni thus far). It's mindblowing (hur hur) that the nervous system acts as a self-powered generator that controls and regulates all processes that you as a person carry out.

[Yacoubb]

If I were to approach that answer, it would probably involve discussing how an action potential is initiated as an excitatory neurotransmitter signal binds to a post-synaptic membrane receptor, to continue conducting the action potential through the neuron, across the axon. But again, this seems to vague. How can I add more without necessarily talking about Na+/K+ ions?

[vox nihili]

What?! It was easily one of the most interesting parts of the previous study design (and of uni thus far). It's mindblowing (hur hur) that the nervous system acts as a self-powered generator that controls and regulates all processes that you as a person carry out.

It's cool overall, but I really couldn't give a rat's arse which channels are open when and ahhhh the exact details are so annoying with it!
Kudos for the mindblowing though...very nice hahaha!

If I were to approach that answer, it would probably involve discussing how an action potential is initiated as an excitatory neurotransmitter signal binds to a post-synaptic membrane receptor, to continue conducting the action potential through the neuron, across the axon. But again, this seems to vague. How can I add more without necessarily talking about Na+/K+ ions?

It's asking you how the action potential travels down the post-synaptic axon. The fact it's mentioned the axon specifically suggests it probably doesn't want you talk about how the action potential is initiated.

[simpak]

Did u no the nervous system ALSO regulates the migration of immune cells?