VCE Biology Question Thread

[Mr West]

hey guys,

I understand that memory cells remember the antigens of a particular pathogen they have been exposed to, which enables a quicker response during the secondary response, but I'm wondering how? what do they do when exposed to the pathogen again?

also, what are the functional differences between t memory cells and b memory cells?

lastly, when a b cell is exposed to a pathogen with an antigen it can bind to, does it differentiate into both plasma and memory cells? and is this the same for t cells proliferating into cytotoxic t cells and helper t cells after being exposed to a pathogen with a complimentary antigen?

any help would be great, thanks

[vox nihili]

Do we need to know the different types of monoclonal antibodies and their uses?

No

hey guys,

I understand that memory cells remember the antigens of a particular pathogen they have been exposed to, which enables a quicker response during the secondary response, but I'm wondering how? what do they do when exposed to the pathogen again?

also, what are the functional differences between t memory cells and b memory cells?

lastly, when a b cell is exposed to a pathogen with an antigen it can bind to, does it differentiate into both plasma and memory cells? and is this the same for t cells proliferating into cytotoxic t cells and helper t cells after being exposed to a pathogen with a complimentary antigen?

any help would be great, thanks

They're really just the same cells that respond to the antigens in the first place. So the memory cells are just more cells that can respond to that antigen. Then they respond in the same way.
Yes to B-cells differentiating into both of them. No to T-cells.

[PhoenixxFire]

and is this the same for t cells proliferating into cytotoxic t cells and helper t cells after being exposed to a pathogen with a complimentary antigen?

This actually came up last year as well. T cells don’t differentiate into Tc and Th cells. When they leave the thymus they are already either Tc or Th. Tc cells differentiate into active Tc and memory Tc cells, Th cells differentiate into active Th cells and memory Th cells.

What are the steps leading to an autoimmune disease and an immunodeficiency disease?

What do you already know about these?

[PopcornTime]

What are some characteristics of cellular and non-cellular pathogens?

Also, are viruses non-living because they are incapable of undergoing metabolism?

[vox nihili]

What are some characteristics of cellular and non-cellular pathogens?

Also, are viruses non-living because they are incapable of undergoing metabolism?

What do you think? These are questions you could do some of your own research on.

[nicholas9027]

Hi guys
i need help with these true or false questions:
People born without B cells can mount a fully functional adaptive immune response against a virus.
An allergy is caused by the body's immune response is to a self antigen.

Thanks in advance

[PhoenixxFire]

Hi guys
i need help with these true or false questions:
People born without B cells can mount a fully functional adaptive immune response against a virus.
An allergy is caused by the body's immune response is to a self antigen.

Thanks in advance

Hey!
We're more than happy to help you, but whilst it would help right now for us to give you the answers, it won't help you understand the content.
So, I'm gonna give you a couple of prompts and see whether you can work out the correct answer from that.

1. What cells are involved in defence against a virus? What are B cells used for?

2. What are some common allergens you can think of? What's a self antigen? Are those allergens self antigens?

If you want to take a guess at it and explain your reasoning I'm happy to check it for you

[nicholas9027]

Hey!
We're more than happy to help you, but whilst it would help right now for us to give you the answers, it won't help you understand the content.
So, I'm gonna give you a couple of prompts and see whether you can work out the correct answer from that.

1. What cells are involved in defence against a virus? What are B cells used for?

2. What are some common allergens you can think of? What's a self antigen? Are those allergens self antigens?

If you want to take a guess at it and explain your reasoning I'm happy to check it for you

Well this my reasoning for my question. Since B and T cells are apart of the adaptive immune response, when a person is born without B Cells. I believe that their T cells can still mount a immune response against virus, however im not too sure because it may be too weak with out the B cells??
Common allergens such as pollen bind to IgE on a mast cell. So i believe the answer is False as IgE is an antibody not a self antigen. (correct me if im wrong)

[PhoenixxFire]

Well this my reasoning for my question. Since B and T cells are apart of the adaptive immune response, when a person is born without B Cells. I believe that their T cells can still mount a immune response against virus, however im not too sure because it may be too weak with out the B cells??
Common allergens such as pollen bind to IgE on a mast cell. So i believe the answer is False as IgE is an antibody not a self antigen. (correct me if im wrong)

You're correct for both.
1. I'm actually not entirely sure what they would want you to say given VCE tends to ignore some of the finer details. Given it says 'fully functional' I would go with false. Whilst cytotoxic T cells will bind to and kill infected cells, they don't fully differentiate and proliferate until cytokines are released by a T helper cell, which requires a B cell to be activated. So there will be some response to the virus, but it won't be a full response

2. You've got the correct answer, but you've gotten to it in the wrong way. That IgE is an antibody doesn't matter, the question is asking if allergens are self antigens - which they are not. The body's response to a self-antigen will result in an autoimmune disorder not an allergy.

[Bell9565]

You're correct for both.
1. I'm actually not entirely sure what they would want you to say given VCE tends to ignore some of the finer details. Given it says 'fully functional' I would go with false. Whilst cytotoxic T cells will bind to and kill infected cells, they don't fully differentiate and proliferate until cytokines are released by a T helper cell, which requires a B cell to be activated. So there will be some response to the virus, but it won't be a full response

Just further to this point, and to answer your question with a little more depth nicholas9027, pretty much B cells act on extracellular pathogens and T cells act on intracellular pathogens. If you remember it that way (a bit of a simplification but still) it will help with these types of questions. Although we think of virus particles as usually being intracellular, there are times at which they are out of the cell (when moving to infect a cell) so this is where your B cells come into play. PhoenixxFire, I was unaware that B cells were required to allow T helper cells to release cytokines to activate cytotoxic T cells - could you please elaborate because I'm genuinely interested haha. But yeah in summary you can mount a fully active cell mediated response but you wont have an humoral response and since both are part of adaptive, well i'm sure you can gather the answer. 

[PhoenixxFire]

I was unaware that B cells were required to allow T helper cells to release cytokines to activate cytotoxic T cells - could you please elaborate because I'm genuinely interested haha. But yeah in summary you can mount a fully active cell mediated response but you wont have an humoral response and since both are part of adaptive, well i'm sure you can gather the answer.

I don't really know how it works in that much detail. My teacher described it as a final check to make sure that the antigen they are reacting against is actually non self - so a B cell and a Th cell both have to have the same antigen specificity for an immune reaction to occur.

After the B and Th cell bind their antigen they find each other and the B cell presents the antigen it bound to the Th cell (I believe on an MHC2 marker). That's when the Th cell will release the cytokines that stimulate Th, B, and Tc cells.

That's why I was kind of unsure what VCAA expects you to know - without the B cells you wouldn't have the cytokines being released. I'm not too sure how much Tc cells can do without the cytokines, but they won't be able to do it as efficiently as if there was B cells.

This was all from my teacher in one lesson a year ago so i'm not sure how accurate it is or how well I'm remembering it haha

[PopcornTime]

Why do neurotransmitters require vesicles if they are hydrophilic? Is it just because they are large?

[PhoenixxFire]

Why do neurotransmitters require vesicles if they are hydrophilic? Is it just because they are large?

Hydrophilic molecules aren’t able to cross the plasma membrane, hydrophobic are

[PopcornTime]

If the biology exam at the end of year is out of 120, how many marks would need to be lost to receive a 47-48?

[Sine]

If the biology exam at the end of year is out of 120, how many marks would need to be lost to receive a 47-48?

depends on the year but i know in previous years you have been able to drop a lot for those scores. Something like 8-12.