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Describe and explain how the alveoli are adapted to perform efficient gaseous exchange

The alveoli are arranged in clusters at the end of the bronchioles in the lungs. The lungs contain an extremely large surface area of alveoli (around 70m2) which acts to provide the maximum space for the exc...
JP
Answered by Joe P. • Biology tutor
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Describe the sodium-potassium ion pump on cell plasma membranes (2 marks)

These pumps use ATP / active transport to move 3 sodium ions (Na + ) out of the cell for every two potassium ions (K + ) that move in.1 mark - idea of active transport / use of ATP1 mark - idea of 3 Na + and...
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Answered by Aarif A. • Biology tutor
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Describe the process of DNA replication.

DNA helicase unwinds the DNA double strand / causing hydrogen bonds between complimentary base pairs to break / both single strands used as templates / DNA replication is semi conservative and semi discontin...
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Answered by Leia Z. • Biology tutor
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Describe the Darwinian theory of natural selection (GCSE/A-Level)

Every individual of every species living on the planet has DNA, made up of sections called genes. Mutations to these genes occur over time, resulting in a change to an individual's behaviour or physiology. T...
BD
Answered by Bill D. • Biology tutor
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What’s the difference between a eukaryote and a prokaryote?

A prokaryote will not contain membrane-bound organelles, whereas a eukaryotic cell will contain membrane-bound organelles.Examples of membrane bound organelles would be the nucleus, mitochondria and chloropl...
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Answered by Camilla M. • Biology tutor
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