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Biology
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Describe the process of phagocytosis and how antigen presentation leads to antibody production (9 marks)

White cell (macrophage/neutrophil) detects bacteria antigen by binding to cell surface receptorsWhite cell engulfs bacteria (this is endocytosis), bacteria is held in a phagosome Lysosomes enter phagosome...

CR
Answered by Caine R. Biology tutor
2985 Views

Tobacco smoke contains carbon monoxide. Explain how carbon monoxide affects a persons ability to exercise.

Carbon monoxide is a poisonous gas. It binds to haemoglobin in red blood cells irreversibly. This means that less oxygen can be carried by red blood cells. As oxygen delivery decreases to muscles and so l...

HP
Answered by Hersh P. Biology tutor
4311 Views

Explain how eutrophication can result in low oxygen levels in the water in the stream.

Eutrophication occurs when excess nitrates from fertilisers seep into the stream. The nitrates cause algal bloom on the surface of the water. As a result, sunlight is blocked from reaching the plants unde...

NB
Answered by Nadia B. Biology tutor
4014 Views

List 3 similarities and differences between the structure of a plant cell and an animal cell

Similarities:They both have a cell membraneThey both have a nucleusThey both have cytoplasmDifferences:A plant cell has a cell wall but an animal cell doesn'tA plant cell has a vacuole but an animal cell ...

SR
5227 Views

Describe ways in which a healthy artery differs from an artery affected by coronary heart disease

A healthy artery is wider and has no blockages. The lumen (which is the hole in the centre of the artery), is open and clear. This means there is more blood flow. An artery of a person suffering from coro...

AS
Answered by Aleksi S. Biology tutor
20649 Views

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