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How does the presentation of a virus antigen by a macrophage lead to antibody production against the antigen?

T helper cells recognise and bind to the antigen and become activated. The activated T helper cell stimulate B cells to form plasma cells that produce and release antibodies that are specific to the viral an...
PP
Answered by Prakruthi P. • Biology tutor
3733 Views

How does an action potential propagate?

a stimulus depolarises the membrane potential above the threshold level e.g. -40 mvthis causes voltage gated Na+ ion channels to open- resulting in an influx of Na+ into the cellthis depolarises the membrane...
SA
Answered by Syed A. • Biology tutor
2688 Views

Describe the stages of phagocytosis (4 marks)

the phagocyte recognises the antigen on the pathogen surface as foreignThe phagocyte cytoplasm moves around the pathogen, and the membranes fuse, forming a phagosomeLysosomes containing lysozymes fuse with t...
AM
Answered by Aislinn M. • Biology tutor
11368 Views

Describe the process of DNA transcription:

The DNA double helix unravels as helicase breaks the hydrogen bonds between base pairs. RNA polymerase binds to the promoter region on the DNA strand. The RNA polymerase transcribes the DNA coding strand by ...
EC
Answered by Erin C. • Biology tutor
7848 Views

Describe the process of the Krebs cycle.

Acetyl CoA (2 carbon compound) from the link reaction combines with a 4 carbon compound called oxaloacetate. This reaction releases the CoA enzyme allowing it to be re-used. The now 6 carbon compound (citric...
CS
Answered by Chloe S. • Biology tutor
10419 Views