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How is ATP produced in the mitochondria?

The Krebs cycle produces ATP by substrate level phosphorylation. The cycle is completed twice per glucose molecule. It also produces NADH which goes on to donate an electron to the electron transport chain o...
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Answered by Emily M. • Biology tutor
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How is blood glucose concentration regulated, with reference to insulin, glucagon and the liver?

• The alpha and beta cells monitor the concentration of glucose in the blood • The normal blood glucose concentration is 90mg of glucoses in every 100cm³ of blood • If the concentration rises or falls away f...
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Answered by Gabriel A. • Biology tutor
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Muscle contraction is a chemical process involving proteins. Explain how skeletal muscle contracts.

The best way to approach these type of questions (worth 8 marks) is to explain everything step by step. This will make it much easier for you to explain under stressful exam situations as well as for the exa...
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Answered by Hilary L. • Biology tutor
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How is a nervous impulse transmitted across a synapse?

A nervous impulse is transmitted across the synapse from a pre-synaptic neurone to a post-synaptic neurone through the use of neurotransmitter diffusion. To explain this in more detail let’s take the example...
MW
Answered by Marnie W. • Biology tutor
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During the light-independent reaction of photosynthesis, CO2 is converted into organic substances, describe how.

The light-independent reaction (Calvin cycle) takes place in the absence of light. Firstly, CO2 combines with ribulose biphosphate (RuBP) to produce two molecules of glycerate-3-phosphate (GP). GP is reduced...
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Answered by Tom T. • Biology tutor
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