I think we can say that this is one of the harder MC.
Did you end up asking the major about B cells engulfing the antibody-antigen complex, and then presenting fragments on it's MHC II markers? (It was I think about 3 days ago, just curious to see if this is correct or not)
Also, do we need to know about memory T cells in VCE Bio? If so, is it as simple as T helper cells form a complex with MHC II markers from macrophages, and they then proliferate into memory and effector helper cells?
Don't know what ended up happening with her. She typed up the answer and showed me what she was going to say but obviously never posted it, odd!
Basically, the reason the answer is C is because a loss of thymal tissue reduces the body's capacity to form new, so-called naïve T-cells but not new memory cells. Memory cells are formed from existing T-cells, and there is already an abundance of these floating around.
As to your second question, cosine, about the B-cells: I could have answered this one myself. B-cells are able to endocytose pathogens and fragments thereof and present those pathogens on an MHC class II molecule. Whether or not this is mediated by interactions between the pathogen and the antibody is not particularly important. The B-cell's role as an antigen-presenting cell is fairly minor; dendritic cells are the movers and shakers here.
Where do these primers come from in the nucleus? Like I know they are DNA sequences which essentially start off the RNA Polymerase, but where, and how do these primers themselves attach to the DNA molecule without the assistance of RNA Polymerase? (Considering that RNA Polymerase uses these primers to attach nucleotides, what assists these primers to attach in the first place?)
Also, are antibiotics antibodies in the medicine? Dumb question but I had to say it... If they are, then why are antibodies effective against viruses but antibiotics not effective?
If it isn't, why are antibiotics not effective against viruses anyways? Sure, they're intracellular, but same goes with antibodies, how can an antibody neutralise a virus if it is inside a host cell?
Really, really critical point here everyone seems to have missed:
only DNA polymerase needs a primer. RNA polymerase DOES NOT need a primer.
DNA polymerase needs a primer because of the way the enzyme works essentially. It can only attach things to the 3' end of existing strands. RNA polymerase is a whole other kettle of fish. It can make things from scratch. Indeed, primase is a type of RNA polymerase (which is kind of obvious when you think about it; it makes an RNA polymer after all).
As far as antibiotics are concerned, they are small molecule drugs that are able to interact with various molecules inside of bacteria and, essentially, inhibit them. They are targeted against molecules that are endogenous to bacteria but are not found in human cells.
That antibiotics are not effective against viruses is more about nomenclature than anything else. Anti=against, bio=life. Viruses aren't a form of life. Antibiotics are just what we call drugs that kill bacteria. Anti-virals, which obviously kill viruses, work in essentially the same way as antibiotics; they target enzymes in viruses that we don't have as a means of killing the virus.
Home
Help
Search
Login
