Gene technologies

Question 1

What is genetic screening?

Answer 1

Analyzing an individual’s DNA to look for a specific gene.

Question 2

What is the purpose of a DNA probe?

Answer 2

It can identify the presence of certain genes.

Question 3

How does a DNA probe work?

Answer 3

The DNA probe has a specific DNA base sequence that is complementary to the gene. It is also fluorescent meaning that if the gene is present in the DNA it will bind to it and it will be identifiable.

Question 4

What is genetic fingerprinting used for?

Answer 4

To produce a unique fingerprint of a person’s DNA.

Question 5

What does genetic fingerprinting involve?

Answer 5

Analyzing the introns of an individual’s DNA as it contains repetitive sequences called variable number tandem repeats.

Question 6

Why are VNTRs used for genetic fingerprinting?

Answer 6

The number and length of these in unique to each person.

Question 7

What are the steps to genetic fingerprinting?

Answer 7

1. Extraction
2. Digestion
3. Separation
4. Hybridisation
5. Development

Question 8

What happens during digestion?

Answer 8

1. The DNA is cut into smaller fragments using restriction enzymes that cut just outside the VNRTs.
2. Separate the DNA fragments using gel electrophoresis and then transport the fragments to a nylon membrane.
3. Add DNA probes to label the fragments.
4. Place the development membrane onto an X-ray film
5. This will reveal dark bands where the DNA probes are attached.

Question 9

How does gel electrophoresis work?

Answer 9

1. The DNA is cut into smaller segments by restriction enzymes.
2. The segments are loaded onto wells that contain a porous gel.
3. The gel floats in a buffer solution within a chamber between two electrodes.
4. When an electric current is passed through the gel the DNA strands move towards the positively charged electrodes.
5. The smaller the DNA fragment the further and faster it moves up.