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Biology
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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...

PP
Answered by Prakruthi P. Biology tutor
3034 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 membr...

SA
Answered by Syed A. Biology tutor
2161 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 wit...

AM
Answered by Aislinn M. Biology tutor
9224 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 ...

EC
Answered by Erin C. Biology tutor
6263 Views

Compare anaerobic respiration in a yeast cell with anaerobic respiration in a muscle cell.

Anaerobic respiration in yeast cells produces carbon dioxide and ethanol. Whereas anaerobic respiration in muscle cells produces lactic acid only.Both, however, do produce little amounts of ATP (energy)

CS
Answered by Chloe S. Biology tutor
2379 Views

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