OCR Biology A-Level Specific Defense Summary

Antibodies : Y shaped glycoproteins (immunoglobins) that can bind to two
pathogens
↳ .
Act as opsonins/anti-toxins
Prevent
pathogens invading the host
·
cens


Agglutinate pathogens together for easier digestion
·




T-lymphocytes :
Come from the
thymus gland and respond to altered cens -> viruses/cancers
-helper sells Bind to antigen presenting cens to produce interleuking
·
:




↳interleukins Stimulate B-caus other T caus and
macrophages
:


,



·

I killer cells :

Produce perforin which hills
pathogens by making holes in the membrane
·
I Help with immunological memory
memory sens
:




F conditions
Regulatory cells Stop the immune response to
prevent autoimmune
· :




1
Phagocytosis forms antigen presenting ceus
.




2
Receptors on T-helper caus fit the antigens activating the T-helper
.


,
Cens
3 The
T-helper cells rapidly divide producing
. :




T-memory cells
divide
Interleukins to stimulate
phagocytosis/B ceus to
·




·

T-killer cels




B-lymphocytes Come :

from bone marrow and respond to extracellular
antigens - bacterial fungi
plasma Produce antibodies
·

cells :




B-effector Cells Divide to produce plasma cels
·
:




B-memory caus Help with immunological memory
·
:




1 The activated -helper binds to the B-cel with the correct
cen
antigen->clonal Selection
.




2
. Interlechins activate the B-ceus

The activated B-effector cell produces
plasma ceus and B memory cells
.
3 ->
clonal expansion
4 Cloned
plasma cells produce antibodies -
primary immune response
.




3 .


Upon a second infection B-memory cels rapidly produce antibodies Secondary immune response


Autoimmune disease When the immune self and attacks
Symptom stops recognizing the healthy cells
:




↳
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