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)

                          Sorry there chimichurri I missed that second part! Moskva Is right!

                          In Photosynthesis: water is split using sunlight; and this releases electrons. These electrons are used to load NADP+ into NADPH. Also, hydrogen ions (H+) are released. These build up on one side of the membrane, creating a 'proton gradient'. (Since there is a lot of them on one side, they want to diffuse to the otherside). They then pass through this protein called ATP Synthase, which acts like a watermill; adding the third phosphate group to ADP; forming ATP!

                          This ATP is then used up in the light independent stage - which produces glucose.

                          So while photosynthesis does produce ATP; it's only in the first light dependent stage. There is none left over at the end!

                          This may sound similar to the Electron Transport Chain! In fact: it is! Except the direction of H+ ion flow is the opposite, and other reactions happen (Such as FADH, etc...) and the H+ ions come from the NADH/FADH produced in the krebs cycle etc... (instead of water).

                          Moving back a bit, during glycolysis (when glucose is split); it produces two 'pyruvate' molecules;
                          The thing is, it also takes two ATP to do this. So it is really a net 2 ATP produced (as it takes 2, but makes 4). Note that the atoms in glucose aren't being made into ATP; it's just the electrons!

                          Hence in photosynthesis: Sunlight & Water --> e- --> ATP....... --> Glucose
                          And in Cellular Respiration: Glucose --> e- --> ATP

                          So it's the electrons from ATP that are transferred. Not the ATP molecules!

                          I don't think you need to know all that btw... 😆

                              Secondary responses are extended cellular responses to an antigen utilising specified cells such as Phagocytes and Monocytes while primary responses are shorter lived and more often preventative toward antigens such, (skin, stomach acid etc).

                                7 days later

                                Moskva sure, its from 2008 exam 1, question 5 b. and yep that does make sense, ig the cells in the tissue would be considered an intracellular pathogen bcos of the mhc 1 markers?

                                    Hi, RBCs aren't nucleated therefore they don't have MHC 1 markers. So how are they identified as self/non-self? And how can blood transplants be rejected from the recipient's body?

                                      bioho4

                                      RBCs don't have MHC/HLA markers but some will have "red cell antigens". Most times these atigens will fall under either type-A or type-B (there are a few minor ones but they are very very uncommon so don't worry about it).

                                      You may have heard of the term "blood type", which can be either O, A, B or AB (for all intents and purposes).

                                      • People with type-O blood type have no red cell antigens on their red blood cells.
                                      • People with type-A blood type have type-A antigens on their red blood cells.
                                      • People with type-B blood type have type-B antigens on their red blood cells.
                                      • People with type-AB blood type have both type-A and type-B antigens on their red blood cells

                                      Ok, due to Immunological Tolerance, and the relatively conservative nature of these A and B antigens, people with a certain blood type will be able to accept any blood with the same or less antigens. Since they are recognised as self. That is to say, a person with type-A blood will be able to accept Type-O (no antigens, less) and Type-A (same) blood; but not Type-B or Type-AB blood.

                                      Blood transplants are rejected is because the antigens in the transfusion are not recognised as self (i.e. foreign).

                                      EDIT: just to be extra clear, this is quite a simplified view of blood types, as there are more red cell antigens types than just A and B; rhesus factors also need to be taken into consideration (which is technically just another type of antigen).

                                        bioho4

                                        Ah ok I see,

                                        The VCAA question explicitly states a tissue has entered the body; presumably transplanted but that doesn't really matter.

                                        And, yes, MHC class 1 on the cells of the tissue is what allows Cytotoxic T Cells to recognise them.

                                        Also, the cells themselves aren't considered pathogens, just foreign.