prettypink1881 The stem of that part of the question says the probes attach only to complementary sequences on particular viruses. So if a probe didn't exist with that particular complementary sequence then it wouldn't work because the probes are required for RT-PCR. I think?
VCE Biology Questions Thread
jessh24 No. In the biology FAQ document, it specifically states that knowledge of convergent and divergent evolution is not needed. You just need to know what homologous, analogous, and vestigial structures are (this is basically convergent and divergent evolution anyways). However, divergent evolution is basically just regular evolution, thus you may need to know it.
jessh24 yeah that makes sense, thanks!!
Does anyone know if we need to know specific ways that scientists use CRISPR technology to modify organisms like non-homologus or homologous end joining?
Meep<3 You do not need to know the specifics of NHEJ and HDR. You simply need to know that genes can be knocked in and out.
ohh okk thankss
does anyone know how the adaptive immune response rejects a transplant organ? is it the same in that apcs engulf the foreign antigens etc, or is it different?
prettypink1881
Your body rejects an organ when its antigens arent the same as yours, so it will recognise it as non-self and basically initiates the adaptive immune response to get rid of it
Taaaa76 thanks!
I had a question, when the helper T cells are activated by an antigen-presenting cell, how does it know whether it should activate a B lymphocyte or a cytotoxic T cell? So in other words how does the T helper cell know if it should activate the cell-mediated response or the humoral response?
Meep<3 I don't think we need to know "how they know", but the cell mediated response will be initiated if the pathogen is intracellular, and has invaded a cell ie a virus. the humoral response will be initiated if the pathogen is an extracellular pathogen. both a t helper cell and a naive t or b cell need to be selected by the same antigen for the response to happen. i think.
Ok thank you
prettypink1881
I thought both were activated regardless wether it was intracellular or extracellular?
So if someone had a bacterial infection, the cell mediated response wouldnt be initated at all?
Maybe there like certain extra steps that are taken for each type of response to be initiated but its just not part of our scope?
I searched it up and uhh bacteria can be both intracellular and extracellular so it does trigger the cell mediated as well
It probably just varies then. Thanks for the info!
Taaaa76 I don't think need to know it to that level; if we get a short answer question abt a specific adaptive immune response and its clear that it has invaded that cells, then u would talk about cell mediated by saying t helper cell releases a naive t cell then tallk about clonal expansion into cyotoxic and memory t cells and what they both do.
if its clear in the stem question that its extracellular then you can just say helper t cell selects a naive b cell which clonally expands into plasma and memory b cells and explain what they do.
so basically if you were to say in a short answer question that both are activated, tehn you would have to explain all the subsequent steps after activation of BOTH of them- which would probably take a while to write- but if you feel like you'll have enough time to write it then it should be fine and you probably won't get marks off.
I did a prac exam recently and i wasnt sure whether the pathogen was intra or extra cellular so i talked abt both cell mediated and humoral and the marking scheme showed it was fine but I didnt actually need to write both.