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Describe how phagocytosis of a virus leads to presentation of its antigens (3 marks)

Virus engulfed by phagocyte (broad immune response), destroyed using lysosomes (hydrolysis) and viral antigens presented on cell membrane (trigger specific immune response e.g. anti-bodies).
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Answered by Ben J. • Biology tutor

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Describe the function of enzymes DNA helicase and DNA polymerase during DNA replication (2 marks)

DNA replication occurs in two phases: DNA separation (DNA helicase) and DNA transcription (DNA polymerase)
Enzyme Function:
1. DNA helicase – (unwinding ...

Answered by Ben J. • Biology tutor

9740 Views

What is the sequence of events for muscle contraction?

· The myosin head attaches to the myosin binding site on the actin filament forming an actinomyosin bridge· ATP is hydrolysed to ADP and inorga...

Answered by Letisha B. • Biology tutor

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How does insulin contribute to the regulation of blood glucose control?

When high levels of glucose are detected in the blood, for example after a big meal, insulin is released from beta cells in the Islet of Langerhans. These are clusters of cells present in the pancreas.

Answered by Leah C. • Biology tutor

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How do we know whether our results indicate whether or not there is a relationship between our variables?

We can test for 'significance' in order to determine whether it's likely that the results that we see are due to random chance or due to a relationship between them. This involves using a statistical test...

Answered by HENRY S. • Biology tutor

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