Question

please!

Assay questions 5 points each 1-What RFLP stand for and what RFLP analysis test for? 2-Why do you add sample loading buffer to DNA sample prior to loading sample into agarose gel. 3-In cheek DNA extraction procedure, name two steps that helped to break (lysis) the cheek cells. 4- Would a shorter DNA fragment move faster or slower through agarose gel, why.

Answer 1

Answer:

1)

RFLP is Restriction Fragment Length Polymorphism.

This is a technique that explain variation in homologous DNA sequences known as polymorphism.

This distinguish individuals, species or populations.

This also help to pinpoint location of genes within a sequence.

Here DNA is devided into fragments by Restriction endonucleases. The resulting fragment is separated by gel electrophoresis.

2)

DNA Loading buffer contain coloured dye and density agents.

Loading dye is mixed with DNA samples for use in agarose gel electrophoresis.

Dye helps to assess how fast DNA is moving in electrophoresis.

DNA is mixed with 6x sample loading buffer in gel wells.

Loading buffer also increases density of the sample.

This enable DNA molecules to sink into the wells.

3)

Cheek cells are easy to obtain, just by a swirling movement.

The cheek cells are treated with 3 agents detergent, then enzymes and finally alcoho to lyse and obtain DNA.

Treating with detergent break down plasmamembrane and nuclear membrane. This is because membranes are formed of lipids.

Then add enzyme( meat tenderizer), they are proteases so they break down protein and unwind DNA strands.

Cold alcohol reduces solubility of DNA. DNA precipitate into alcohol. Proteins and lipid remain in solution.

4)

The negatively charged DNA moves to positive part in agarose gel. Shorter DNA fragments move faster than longer. So shorter fragments move longer. This is due to effect of gravity and density gradient. Gravity effect and density gradient will be lower for shorter fragment.