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.

      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

            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.

                  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.

                          prettypink1881 yes you don't need to know about it in detail. From memory, VCAA usually focuses on bacteria being extracellular, but many would still initiate the cell-mediated response because they can invade host cells. In reality, biology is a lot more complex haha. However, if you were asked to explain the third line of defence in relation to bacteria, I would usually just stick with the humoral response for sake of time and the marking scheme since all bacteria will definitely initiate this response.

                            does anyone know if we are allowed to use pencil to draw flow charts, phylogenetic trees and any type of drawings on the exam?

                              Lemonade_222 you can use pencil but it need to be quite dark (so it will show up on the scanned copies) and not a really smudgy lead (this will ruin your other pages). Pen is always best, but I did my whole exam in pencil and was absolutely fine. Unless the rules have changed since last year, I think you'll be okay.

                                What is the dating period of potassium argon dating and uranium lead datin?

                                  @"Taaaa76"#p16146this is from my textbook, idk what the brackets for the uranium lead one is supposed to mean though.

                                  Uranium-235 – lead-207
                                  dating period:1 million – 4.5 billion years (used together with U-238 – Pb-206 dating)

                                  Potassium-40 – argon-40
                                  dating period: 100 000 + years