Edexcel GCE Biology Unit 4 6BI04 June 2013

Its actually active artificial immunity, the vaccine can involve either: weakened virus/bacteria (so its harmless); toxin that's been altered into an harmless form; or an actual part of the pathogen containing the antigen (non self) that leads to specific immunity.

Vaccinations are a form of artificial active immunity, where the weakened form of a pathogen is injected into the body (the antigens still function though).
Cells of the immune system can bind to the antigens (provided they have the specific shape on their receptors) and specific antibodies can be made.
I think in this case, the humoral response occurs( eventually resulting in B memory cells and B effector cells):
- The B memory cells are able to 'remember' the pathogen - in case of secondary infection
- The B effector cells become Plasma cells, which then produce the required antibodies.

Did anyone take this in January? Possibly the worst paper I've ever seen, pure dirt

Did anyone take this in January? Possibly the worst paper I've ever seen, pure dirt

This is a synoptic paper right?

Not exactly.
There could be questions on core principles though, from unit 1 and 2, especially for the ecology or DNA chapters

Edit: I JUST saw a question on mitosis and plant tissues [June 2011]

can anyone explain me the difference between hypothesis, observation, prediction and theory?

Sample question
Q. The student thought that the behavious and distribution of the woodlice was being influenced by an abiotic factor. Was this:
a.hypothesis
b.observation
c.prediction
d.theory?

I was wondering how manipulating the above question would change it to each of the four options as well.

I've been doing a few past papers and noticed quite a lot of AS stuff is coming up.

What AS stuff have you guys revised (besides the questions that have already come up?)

B cells label the bacteria as foreign objects and this allows phagocytes to engulf the bacteria. Basically they can recognise the bacteria they need to kill a lot easier.
I hated that question

just to confirm, it s both B cells and macrophages that can label the antigen in order to genertae specific antibodies , right? or not....?

Stimulated B cells> B effector cells> Plasma cells> antibodies.
The B cells (indirectly) lead to antibodies being produced, these antibodies bind to specific antigens on the bacteria (labelling them). this labeling, therefore allows macrophages and other phagocytes to identity them more quickly.

ok i m confused now does 'labelling' implies that only the antibodies synthetised by b cells aggregate to their matching antigens , making a complex easier to be detected and engulfed by phagocyte?.....