Top answers

How should I study for the A-level exams?

The best thing to do is making your own notes and making sure that you understand the topics. And then, you can start doing past papers (without looking back to your notes), and see which topics in particula...
BM
Answered by Bonnie M. • Biology tutor
3377 Views

What happens during eutrophication?

The addition of nutrients such as nitrate means that nutrients no longer limit plant growth.Algae begins to bloom which blocks out sunlight. As a result, plants cannot photosynthesise (or photosynthesis is r...
EC
Answered by Emily C. • Biology tutor
3415 Views

How is immunity developed after a primary infection by bacteria?

Phagocytosis - A phagocyte detects the bacteria has foreign antigens and so envelops it with its cytoplasm, packaging it into a phagosome via endocytosis. Lysosomes then fuse with the phagosome releasing hyd...
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Answered by Daniel V. • Biology tutor
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In some parts of Africa, where malaria commonly occurs, there are higher frequencies of the allele that causes sickle-cell anaemia.

Individuals with the recessive sickle-cell anaemia allele have a lower chance of developing severe malaria. Therefore, they are more likely to survive and reproduce than those without the allele. The allele ...
LN
Answered by Laura N. • Biology tutor
3063 Views

Describe the differences between active transport and facilitated diffusion.

Facilitated diffusion is a passive process that occurs down a concentration gradient. Active transport requires energy (from ATP) to allow movement of substances against a concentration gradient.
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Answered by Laura N. • Biology tutor
4175 Views