Amadas_

No, (Adaptive) Cell-Mediated Responses and Adaptive Humoral Responses can develop simultaneously -- they can be activated at the same time.

You got a trick question (or alternatively a bad question) 😀. Because:

  1. Any pathogen able to stimulate an Adaptive Immune Response, can in theory, stimulate both responses. (note the "in theory" bit)

  2. HIV is specifically good at suppressing Adaptive Immune Responses. They do this by targeting cells with the CD4 co-receptor (i.e. Helper T Cells).
    Actually, Helper T cells also somewhat assist in Innate Immune Responses once they are activated because they can heighten macrophage aggressiveness etc... so really the Innate Immune System is also affected by HIV, technically, anyways, so I don't think that second bit matters so much for VCE.

If a virus is named the 'Human Immunodeficiency Virus', there is probably a good reason for it 😉.

    Billzene thanks so much for your help, I actually understand it now!

      chimichurri

      chimichurri Do we need to know about the electron transport chain for the exam? Or if we do, how much do we need to know?

      Yes, you will need to:

      • Know that this is the final step (as far as VCAA is concerned anyways) of Cellular Respiration.
      • Memorise it's inputs and outputs.

          chimichurri

          If a substance can bind to an allosteric site, it automatically makes that substance a non-competitive inhibitor.

            chimichurri

            It is just more efficient this way, especially in Eukaryotic cells with Mitochondria. In these Eukaryotes, glucose breakdown can be focused in specific areas of the cell.

              @chimichurri

              Can you please group your questions together in one message next time? Or at least into groups with similar topics? It makes life easier for people on this thread that way 😁.

              chimichurri

              C4 plants separate the initial carbon fixation stage and the rest of the Calvin cycle over space. In the mesophyll cells, a 4-carbon molecule called oxaloacetate is produced via the help of the enzyme PEP carboxylase. Oxaloacetate is then converted into another 4-carbon molecule called malate. Malate is then transported to the bundle-sheath cells and is broken down to release carbon dioxide, which can then enter the Calvin cycle in a similar manner to C3 photosynthesis light-independent processes. Therefore, C4 plants are more efficient than C3 plants in dry conditions because they can capture more CO2 in less time and the stomata can stay closed for longer to reduce water loss. PEP carboxylase also prevents photorespiration occurring as it has no affinity for binding with oxygen.

              CAM plants separate the initial carbon fixation stage and the rest of the Calvin cycle over time. The stomata opens at night to bring in CO2. PEP carboxylase fixes the CO2 to form oxaloacetate, which is then converted into malate or another organic molecule. The molecule is then stored in the vacuoles until daytime. Once it is daytime, the stomata does not open (prevents water loss) but the plant can still photosynthesise by using the malate/organic molecule that has been transported out of the vacuole, which breaks down to release CO2. This CO2 then enter the Calvin cycle in a similar manner to C3 photosynthesis light-independent processes. Therefore, CAM plants are also more efficient than C3 plants in dry conditions because they can capture more CO2 in less time, and allow the stomata to open for effective exchange over night whilst ensuring that water is not lost during the day (due to increased temperatures during the day causing more water loss). PEP carboxylase also prevents photorespiration occurring as it has no affinity for binding with oxygen.

              Why is water loss a problem? The stomata closes, meaning CO2 cannot enter and O2 cannot exit, causing photorespiration to increase. This is a problem for C3 plants who have no mechanisms to prevent this. C4 plants prevent this by capturing more CO2 in less time and therefore closing their stomata for longer (of course, stomata will still open to release O2, but since more CO2 is present anyway in comparison to O2, the rate of photorespiration will still decrease). CAM plants open their stomata at night to reduce water loss.

              Not sure if this will be helpful because it's quite in depth. In summary, both C4 and CAM plants aim to prevent water loss by either separating carbon fixation and the rest of photosynthesis over space or time. This is to increase the amount of CO2 present, reduce water loss, and reduce the amount of O2 present (to therefore reduce photorespiration).

                Billzene I think you can reply as per normal, but then click "Reply" again on another post.

                Billzene For example, I am now replying to one of your posts from earlier in the discussion thread. 😃

                    How do you explain the process of the lymphatic system in regards to drainage, flow and surveillance?

                      Amadas_
                      Looks like good o'l Bio's changed.... sigh; Just my thought process here (idk if this is right, but hey - it might help):

                      • Surveillance sounds fairly obvious (it provides a sight for antigen presenting cells and lymphocytes to interact)...
                      • Flow might have something to do with how u need to contract mussels in order to 'squeeze' the lymph through (and how the one-way valves prevent it going backwards)
                      • Drainage could either mean where dead lymphocytes go - or how it drains from tissues into a lymph-node? I'm not sure about this.

                      I'm probably wrong tho (vcaa likes abstract terms)

                          Amadas_

                          To add onto

                          God 's answer;

                          Drainage means the lymphatic system drains excess fluid in [body] tissue and redirect it back into the bloodstream.
                          This excess fluid is usually blood plasma that has entered the tissue, and waste fluid from normal cellular metabolism.

                              7 days later

                              Hey guys if anyone has a copy of the edrolo textbook for 3/4 bio I would appreciate it so much, like people said it was kinda good, so I wanna try it out

                              heyyy everyone where is everyone up to in school with the content?

                              hi, does tissue / blood rejection (after transfusion) cause the humoral or cell-mediated response? i came across a vcaa question which says it's only cell-mediated but i don't understand why?

                                bioho4
                                Tbh this question is very similar to: Are viruses eliminated by the humoral response or the cell mediated response?
                                In theory both are activated.

                                But I think the more prominent one would be the cell mediated response. Because it seems more likely that the different markers on the transplant would be recognized as an intracellular threat rather than an extracellular threat, because its on a cell rather than in the blood (where the humoral response is more efficient), like you won't really have the donors cells floating around in the blood, though the humoral response would still be initiated.

                                Hence, I would talk about the cell mediated response rather than the humoral if no information is provided. However, VCAA is very specific in the language it uses for example in the sample exam 2022, 4c short answer, it specifically mentions the response against an intracellular pathogen (cell mediated) so I think if this question was to be asked there would be more context behind it to determine which pathway of the adaptive response needs to be mentioned.

                                  Hey!
                                  Just wondering what the difference between NADP+ and NAD+is?
                                  And does glucose make ATP? Or does it get converted into ATP?

                                    Hi bioho4! Can you please reference the particular VCAA question? Context is always useful.

                                    The answer to your question actually depends on what is being transplanted/transfused.

                                    • If it is a tissue transplant, the immune reaction to the tissue would be a Cell-Mediated response.
                                    • If it is a blood transfusion, the immune reaction to the mismatched red blood cells would be a Humoral response.

                                    That's not to say either won't induce both, though.

                                        chimichurri
                                        NADP+ has an extra phosphate group; and is used in photosynthesis.
                                        NAD+ is used in cellular respiration.

                                        🙂

                                          Hey chimichurri!

                                          I wouldn't worry about the specific chemistry involved.

                                          Just know that they pretty much fulfil identical roles -- acting as electron/proton carriers/donors. With the difference being that NADPH is for Photosynthesis whereas NADH is for Cellular Respiration.

                                          Also it seems like you should revise Cellular Respiration overall 😅 (Glucose is broken down to make energy to synthesise ATP)