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Biology

A Level

Putting bee honey on a cut kills bacteria. Honey contains a high concentration of sugar. Use your knowledge of water potential to suggest how putting honey on a cut kills bacteria. (AQA BIOL1)

Sugar is a solute and is able to dissolve in water. When sugar is dissolved in water, it has a low water potential. Water moves from a high water potential to a low water potential; from where there is a ...

Answered by Charlotte S. • Biology tutor

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What is the Difference between saturated and unsaturated fatty acids?

Firstly, saturated fatty acids are where all the carbon atoms have single bonds between them making the lipid saturated as no more hydrogens can be added. Having

Answered by Katie D. • Biology tutor

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Describe the path of electrical activity through the heart, starting at the sino-atrial node.

The electrical activity is initiated by the pacemaker of the heart, the sino-atrial node at the top of the left atrium. This spreads across the atria before reaching the atrio-ventricular node. Here there...

Answered by Marcus B. • Biology tutor

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Why is oxygen needed in respiration?

In respiration, as you know the electrons travel through the electron transport chain and provide the energy to pump Hydrogen ions across the inner membrane. Once they reach the end of the chain, where do...

Answered by Emma J. • Biology tutor

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Describe three differences between a motor neurone and a sensory neurone.

A motor neurone has no or a very short dendron whereas a sensory neurone has a long dendron. A sensory neurone's cell body is found 'in the middle' of the neurone whereas a motor neurone's cell body is fo...

Answered by Joshua D. • Biology tutor

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