B lymphocytes - A level biology:Watch
I think you youngsters at A level are having a hard time cos with the mind-blowing advances in biology/medicine, your books, in trying to simplify matters, introduce a lot of vists to confused.com and even errors.
The points to understand about humoral immunity mediated by B cells are:-
- B cells form the humoral arm of adaptive immunity [the latter takes over when an actual "invasion" of our bodies starts [innate immunity is a background series of processes that are always active/present]
- When an antigen enters our system, special lymphocytes called recognition cells [which include Langerhan's cells - google it!] with these so-called "glycoprotein receptors" [in your attached pics] on their surface "recognize" the specific antigen that has a complementary structure to this surface receptor, so that the precisely correct/specific B lymphocytes proliferate profusely to generate a massive population of, ultimately, plasma cells that have the capacity to synthesize the SPECIFIC ANTIBODY against the particular antigen.
- These plasma cells have a structure precisely geared to synthesize antibodies ------ so what is their structure? Go on ---- you can work it out - ok take it step by step - what are antibodies chemically? -- yes, you are getting there - they are proteins.
Ok, which parts of cells synthesize proteins? - yes you got it - spell it out - oc ER - so these cells have rich ER with numerous ribosomes. Also making chemical bonds needs energy so................................ it's on the tip of your tongue - .......
......well done! - they have many mitochondria. Easy peasy, yeah?
All these identical plasma cells produce the same identical antibody [called monoclonal - mono = one].
So to come back to your Q and simplify things, the "antibody" on the surface of the cell is only there FOR RECOGNITION purposes - the main antibodies are produced later.
Happy now? Ok you are reading this in your dreams, but wakie wakie! - your mum is waiting with the frying pan with sizzling sausages!