Chemistry 9701 · AS & A Level · Analytical techniques

Analytical techniques — practice question

(a) DNA fingerprinting has become an important method for examining samples from living organisms or organisms that once lived.
(a(i))[1]

Once the DNA has been extracted and purified, what is the initial step in analysing a sample of DNA?

(a(ii))[1]

What method can be used to increase the amount of DNA available for analysis?

(a(iii))[2]

During electrophoresis, amino acids can migrate in different directions or not move at all, whereas DNA fragments always migrate in one direction. Explain why these two observations occur.

(a(iv))[1]

DNA fingerprinting can also be useful in archaeology. Which of the following would not be suitable for analysis by DNA fingerprinting? Put a cross (x) in the correct box(es).

(b(i))[1]

X-ray crystallography can be used to help analyse the structure of macromolecules. What information does this technique provide about a particular macromolecule?

(b(ii))[1]

Which element will appear most strongly in the X-ray crystallography of a biological polymer with general formula $\text{C}_v\text{H}_w\text{P}_x\text{N}_y\text{O}_z$? Explain your answer.

(c(i))[1]

Explain what is meant by the term partition coefficient.

(c(ii))[2]

The partition coefficient for a certain pesticide between hexane and water is $6.0$. A solution has $0.0042\,\text{g}$ of the pesticide dissolved in $25\,\text{cm}^3$ of water. The solution is then shaken with $25\,\text{cm}^3$ of hexane. Calculate the mass of pesticide that will be present in the hexane layer at equilibrium.

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