Immunity as bio

Anyone finding Immunity chapter difficult or am I the only one
Specially clinal selection expansion humoral and cell mediated response
Please give me your feedback
Feeling scared 😦

Reply 1

username5064508

16

You're not alone, barely anyone in my class last year understood it. It doesn't help that the textbooks are full of contradictions and each textbook (I have two) describes it differently, and the specifics very between exam boards. It took me a while to get my head around it. I'd be happy to try and explain it if you'd like and are doing AQA, but I'm not the best teacher 😂

Reply 2

Laboromniavincit

OP

17

Original post by HRobson_BMC

You're not alone, barely anyone in my class last year understood it. It doesn't help that the textbooks are full of contradictions and each textbook (I have two) describes it differently, and the specifics very between exam boards. It took me a while to get my head around it. I'd be happy to try and explain it if you'd like and are doing AQA, but I'm not the best teacher 😂

Please explain humoral response
to start with
sorry for the trouble first thing in the morning of new year
feel so sad Cos I don’t get it

Reply 3

username5064508

16

Original post by Laboromniavincit

Please explain humoral response
to start with
sorry for the trouble first thing in the morning of new year
feel so sad Cos I don’t get it

No problem!
According to my textbooks, the binding of T-helper cells in the cell-mediated response stimulates the rapid mitosis and differentiation of B-cells into B-plasma cells. This is clonal selection.

These B-plasma cells secrete antibodies which have a complementary variable region (binding site) to the antigens on the pathogen, so the antibodies bind to these antigens and kill the pathogen. ( the exact methods aren't covered and I don't think they're important for the spec).

Once the pathogen is gone from the body, some B memory cells remain in the body. If the same pathogen attacks again, the memory cells recognise the antigens and stimulate the humoral response (clonal selection, antibodies) again in higher quantities to wipe out the pathogen as quickly as possible.

I hope that this helped, let me know if there anything else that needs further explaining!

Reply 4

username5064508

16

Original post by Laboromniavincit

Please explain humoral response
to start with
sorry for the trouble first thing in the morning of new year
feel so sad Cos I don’t get it

No problem!
According to my textbooks, the binding of T-helper cells in the cell-mediated response stimulates the rapid mitosis and differentiation of B-cells into B-plasma cells. This is clonal selection.

These B-plasma cells secrete antibodies which have a complementary variable region (binding site) to the antigens on the pathogen, so the antibodies bind to these antigens and kill the pathogen. ( the exact methods aren't covered and I don't think they're important for the spec).

Once the pathogen is gone from the body, some B memory cells remain in the body. If the same pathogen attacks again, the memory cells recognise the antigens and stimulate the humoral response (clonal selection, antibodies) again in higher quantities to wipe out the pathogen as quickly as possible.

I hope that this helped, let me know if there anything else that needs further explaining!

Reply 5

Laboromniavincit

OP

17

Which one is clonal expansion
Thanks for explaining
You are so good

(edited 4 years ago)

OP

Thanks for your time

Original post by Laboromniavincit

Which one is clonal expansion
Thanks for explaining
You are so good

I haven't come across clonal expansion before, but from what I can find online it seems like clonal expansion is the rapid mitosis of B-cells to produce many B-cells, while clonal selection is the differentiation of these B-cells into B-plasma cells to secrete antibodies. In my earlier answer I referred to both processes as clonal selection.

Reply 8

Laboromniavincit

OP

17

Are you a teacher ?
Wish my teacher were as knowledgable like yourself

Reply 9

Jpw1097

19

Original post by Laboromniavincit

Anyone finding Immunity chapter difficult or am I the only one
Specially clinal selection expansion humoral and cell mediated response
Please give me your feedback
Feeling scared 😦

Firstly, you have the innate (or non-specific) immune system and the adaptive (or specific) immune system. The innate/non-specific immune system includes phagocytes which recognise particular antigens on pathogens as well as the complement system (proteins which bind to pathogens and either kill them or target them for destruction by the phagocytes). You do not get memory with the innate immune system, it does not get stronger on re-exposure to the same pathogen - it is the same every time. Do not forget about barrier immunity either - this includes stomach acid, lysozyme in tears, cilia in the respiratory system.

Now let’s break down the adaptive/specific immune system further. Humoral response refers to the production of antibodies by plasma cells (differentiated B cells). Cell-mediated immunity refers to the part of the immunity that does not use antibodies - it uses helper T cells and cytotoxic/killer T cells.
For the specific immune system to be activated, first a phagocyte phagocytoses the pathogen, the pathogen is broken up and then antigens are presented on the surface of the phagocyte. Helper T cells then recognise this antigen and then activate other parts of the immune system including B cells and cytotoxic T cells, activating both the humoral and cell-mediated immune system. This leads to the production of antibodies, cytotoxic T cells kill infected cells, cytokines attract phagocytes to the area.
Clonal selection means the T or B cell that recognises the antigen is activated (because different T/B cells recognise different antigens) and clonal expansion simply refers to this T/B cell proliferating to produce lots more.

Reply 10

Sabav

10

Original post by HRobson_BMC

No problem!
According to my textbooks, the binding of T-helper cells in the cell-mediated response stimulates the rapid mitosis and differentiation of B-cells into B-plasma cells. This is clonal selection.

These B-plasma cells secrete antibodies which have a complementary variable region (binding site) to the antigens on the pathogen, so the antibodies bind to these antigens and kill the pathogen. ( the exact methods aren't covered and I don't think they're important for the spec).

Once the pathogen is gone from the body, some B memory cells remain in the body. If the same pathogen attacks again, the memory cells recognise the antigens and stimulate the humoral response (clonal selection, antibodies) again in higher quantities to wipe out the pathogen as quickly as possible.

I hope that this helped, let me know if there anything else that needs further explaining!

May I ask what resources you use other than the official textbook?

Reply 11

username5064508

16

Original post by Sabav

May I ask what resources you use other than the official textbook?

I use two approved textbooks and supplemental materials, that's about it. The information I have given is what is approved by the exam board so it's what would be most useful to students. I try my best to help so I apologise if I've been misleading, it is not my intention!