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Biology

A Level

Explain what is meant by counter current exchange in fish? Describe how it works and what adaptations the gills have to assist it.

Counter current exchange is the mechanism in which oxygen enters the blood in fish. Blood flows in the opposite direction to the water that flows over the fish's gills. Fish gills have gill filaments and ...

Answered by Katie F. • Biology tutor

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What is the equation for photosynthesis?

6CO2 + 6H2O => (light energy) => C6H12O6 + 6O2

Answered by Melanie T. • Biology tutor

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What are the different hypothesised methods of DNA replication.

There are 3 types: conservative, semi conservative and dispersive.conservative entails the original DNA strand remaining intact with a whole newly synthesised DNA strand being formedsemi conservative enta...

Answered by Ronan F. • Biology tutor

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Explain the process of peptide translation

Following transcription and splicing, mature mRNA travels to the ribosome and displays the start codon. A tRNA molecule which has an anti codon that is complementary to the mRNA start codon matches with t...

Answered by James S. • Biology tutor

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Explain the process of phagocytosis

Phagocytosis is a non-specific cellular defence mechanism by the body which is initiated when a pathogen invades the body and has antigens which are detected as antigenic or foreign – note that antigens a...

Answered by Sam R. • Biology tutor

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