Moskva
also you said that "All pathogens (with the exception of prions) are subject to Adaptive Humoral Immunity response", does this mean virus included as well, as I thought they typically followed cell mediated. If a virus has infected cell it is ...
VCE Biology Questions Thread
chemistry1111
I remember having this exact same question last year lmao.
In reality - I think it's both. An antibody could bind to the capsid (protein coat) of the virus, or even the antigens it leaves on the membrane of the infected cell. But I think, for VCE anyway, it's best to pretend that this doesn't happen.
So if they ask a question about a virus, don't go talking about the humoral immune response.
UNLESS they are referencing an anti-body level graph for vaccinations. (Primary exposure, secondary expose, etc...)
Maybe someone else can give a more definite answer, but my suggestion would just be to work out the vibe of the question, and go from there...
Good luck with your year! 
chemistry1111
"Interferons are a group of signalling proteins made and released by host cells in response to the presence of several viruses. " - Wikipedia
They are sought of like a 'help me' flag. They aren't specific to the virus (hence not part of the adaptive immune response) - and they aren't a type of cell. Rather, they are a protein (like cytokines).
"It is now known that type I IFNs are cytokines produced in response to viral, bacterial, and fungal pathogens, as well as parasites." - Source
I presume it's all types of pathogens - but for written responses, probably just mention for viruses.
- Edited
Yes, antibodies (Adaptive Humoral Response) are incredibly diverse in their functions. They can even target toxins.
In the case of viruses, they can bind to their receptors and prevent them from infecting cells; this is referred to as neutralisation.
Source: Jacaranda Nature of Biology VCE
EDIT: I realised that this could be a bit confusing. So for clarity; just because a pathogen can be targeted by Adaptive Humoral Immunity, it does not mean it cannot also be targeted by (Adaptive) Cell-Mediated Immunity. Viruses are good examples of this, they can be targeted by both.
Does anyone know the answer to this:
What is the immune response in a person receiving their first vaccination? Use the following terms in your response:-plasma cells, memory cells, B cells, antibodies, cytokines
Thanks !
Does anyone know if the cell-mediated response has to occur before the humoral response in order to have T helper cell? Cause I have a question that asks if HIV stimulates a cell-mediated or humoral response and i am unsure.
Upon first vaccination, the humoral immune response is activated where the attenuated pathogen interacts with the b cell that has matching antibodies. The b cell engulfs the pathogen by phagocytosis and presents the antigens on the MHC II markers on the cell's surface. The Th cell binds to the complementary antigen on the MHC II marker and secretes cytokines, that stimulate the B cell to undergo clonal expansion and produce B plasma cell and B memory cells
Hi everyone,
Is anyone able to explain briefly what the difference in function is between the 5' methyl G cap and 3' poly A tail added during RNA processing, as I thought they both functioned to stabilise the mRNA strand but when I came across it in an exam paper it said that the methyl cap protects against attacks from enzymes (which I don't quite understand).
Thanks!
- Edited
When the mRNA travels into the cytoplasm, a class of enzymes that break down RNA (conveniently called RNases) will be like "you've came to the wrong 'hood" and attempt to degrade the mRNA strand. Even in the absence of cytoplasmic RNases, mRNA isn't very stable on its own without modifications and can react with other chemicals in the cytosol. That's why you need the 7-methylguanosine cap to prevent premature degradation of the mRNA before it's translated
Does anyone know if the cell-mediated response has to occur before the humoral response in order to have T helper cell? Cause I have a question that asks if HIV stimulates a cell-mediated or humoral response and i am unsure.
I can't remember exactly, but here's my understanding:
- A T-helper cell is involved in stimulation of both the Cell Mediated and Humoral response.
- HIV attacks and destroys T-helper cells, preventing the production of 'immunity' to new antigens. (Stimulation of clonal expansion/differentiation in b/t cells)
My guess would be that it stimulates the cell-mediated response (it being a virus and all).... but I'm not 100% sure... Maybe someone else can help
Why is glucose expressed as C₆H₁₂O₆ and not just CH₂O? Wouldn't that be simpler?
Do we need to know about the electron transport chain for the exam? Or if we do, how much do we need to know?
Okay, I'm not sure if this question makes complete sense but: do plant cells store energy as ATP or starch? What about animals? Do either of them store it as both?
Again, not sure if this completely makes sense but: I thought one gene coded for multiple amino acids but isn't an operon made of multiple genes that code for one amino acid? So what happened there?
Can substances that aren't inhibitors bind to the allosteric site? And does everything that binds to the allosteric site inhibit substrate from binding to the active site? Or are there some things that can bind without inhibiting?
Does all the energy created by photosynthesis need to go through cellular respiration to become ATP or can some of it - being chemical energy (glucose) be used as is?
How can you tell if a reaction is anabolic or catabolic bc e.g. photosynthesis is anabolic but it also involves the destruction of materials which would mean catabolic right?
What is the main difference between C4 and CAM plants?
- Edited
Why is glucose expressed as C₆H₁₂O₆ and not just CH₂O? Wouldn't that be simpler?
The second formula that you have listed is an empirical formula, whereas the first is the molecular formula. It is the molecular formula that actually tells us the amount of carbon, hydrogen and oxygen atoms in a glucose molecule. You need to make sure that you write the molecular formula as it helps us identify that the molecule you are talking about is glucose, and must be used when writing equations for photosynthesis/respiration.
In the future, please post all your questions in the one post as it makes it easier to answer them all 
I'm don't get how C4 and CAM plants lack photorespiration? If someone could explain this simply I would be super grateful! Thank you!!