DNA Technology

Question 0

What’s the difference between acquired and inherited mutations?

Answer 0

Acquired mutations are limited to the original mutated cell and the cell line produced from it.
Inherited mutations occur in every cell of the body however are not always expressed.

Question 1

What is gene therapy?

Answer 1

Correcting a mutant allele by either repairing it, swapping it with a normal allele or regulating its activity so it no longer produces harmful effects.

Question 2

What is gene cloning?

Answer 2

Making multiple, identical copies of a fragment of DNA.

Question 3

What does reverse transcriptase do?

Answer 3

Converts mRNA to complimentary DNA (cDNA).

Question 4

What does DNA polymerase do?

Answer 4

Catalyses the synthesis of new DNA by the addition of nucleotides to an existing chain.

Question 5

What do restriction endonucleases do?

Answer 5

Cut DNA into fragments. Different REs identify where DNA is by specific base sequences called recognition sequences. If the appropriate recognition sequence is present then DNA will be cut at a location called the cleavage site.

Question 6

What does DNA ligase do?

Answer 6

Ligases can link together DNA strands that have been broken.

Question 7

What does palindromic mean?

Answer 7

Reads the same forwards on one DNA strand as backwards on the complimentary DNA strand.

Question 8

What are sticky ends?

Answer 8

Exposed unpaired bases

Question 9

What do primers do?

Answer 9

Mark out the section of DNA to be amplified in the PCR

Question 10

What happens in a polymerase chain reaction (PCR)?

Answer 10

Double stranded DNA is heated to 95 degrees to separate the strands.
Then cooled to around 65 degrees and primers and nucleotides added. Cooling allows primers to bind to DNA bracketing the DNA region to be copied.
Raising the temp to about 73 degrees enables thermostable polymerase to move along each strand of DNA read it’s code and make a complimentary strand.

Question 11

What is in vitro cloning?

Answer 11

Where gene copies are made within an organism.

Question 12

In electrophoresis what type of fragment travel fastest and furthest?

Answer 12

Small fragments.

Question 13

What are DNA probes used for?

Answer 13

To locate genes or to see if a persons DNA contains a mutated gene.

Question 14

What are DNA probes?

Answer 14

Short strands of DNA that have a specific base sequence complimentary to the base sequence of part of the target gene.

Question 15

How are DNA probes used? Describe the process.

Answer 15

A sample of DNA is digested in fragments using restriction enzymes. The separated fragments are transferred to a nylon membrane & incubated with a fluorescently labeled DNA probe. If the gene is present the probe will bind. The membrane is then exposed to a UV light and if the gene is present there will be a fluorescent band.

Question 16

What is electrophoresis used for?

Answer 16

To separate fragments of DNA.

Question 17

What is DNA sequencing used for?

Answer 17

To read the base sequence of a length of DNA.

Question 18

What is restriction mapping used for?

Answer 18

To make a map of a length of DNA.

Question 19

Why is a southern blot used?

Answer 19

To look for specific sequences in DNA.

Question 20

Why are marker genes used?

Answer 20

To identify cells that have been transformed.

Question 21

What is transformation?

Answer 21

Inserting new DNA (usually a plasmid) into a living cell making it genetically modified, or transformed.