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How does gel electrophoresis seperate DNA?

The DNA from PCR is placed into wells of agarose gel and a buffer solution is poured over it. An electrical current is passed through the gel due to the conduction of the buffer solution. The DNA fragments m...
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Answered by Holly D. • Biology tutor
6357 Views

What happens when some alkali is added to a buffer solution?

The dissociation of the weak acid ‘HA’ would be shown as:HA (aq) ⇌ H + (aq) + A – (aq)Adding alkali will add OH - ions to the solution. These will react with the H + ions present in the solution, producing w...
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Answered by Holly D. • Chemistry tutor
15492 Views

When do I use the subjunctive?

1- What is the subjunctive? It is a mood (not a tense!) which expresses uncertain ideas. 2- So when do I use it? Set phrases with 'que' Negative phrases with 'que' which express emotion or doubt or other unc...
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Answered by Hannah P. • French tutor
2026 Views

Find the exact value of the gradient of the curve y=e^(2-x)ln(3x-2) at the point on the curve where x=2.

This is a typical gradient question for A2 papers, as it requires use of the Product Rule and Chain Rule, as well as knowledge of e^x. Firstly, we can see that we will need to use the Product Rule as e^2-x a...
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Answered by Sophie K. • Maths tutor
10869 Views

How do you use the Passato Prossimo?

The ‘passato prossimo’ tense is the ‘near past’ and the most frequently used past tense in the Italian language, especially used in conversation. The passato prossimo is formed with the auxiliary ‘To be’ or ...
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Answered by Sian W. • Italian tutor
5052 Views