BIOTECHNOLOGY

Question 1

What is biotechnology?

Answer 1

The technique of using cellular processes to make products that are of use to humans.

Question 2

Describe DNA sequencing

Answer 2

DNA sequencing is the determination of the precise order of nucleotides in a sample of DNA. It can be used to show whether a person will develop an inherited disease. By comparing DNA sequences, changed or faulty alleles can be detected.

Question 3

Describe polymerase chain reaction (PCR)

Answer 3

Technique of a series of repeated cycles of duplication using the enzyme DNA polymerase. It features three steps; denaturing, annealing and elongation. It uses taq polymerase as it both contains polymerase and is able to withstand heat.

Question 4

Describe denaturing.

Answer 4

The double helix DNA strand is heated to 96 degrees Celsius. This temperature denatures the DNA strands and separates it into two strands by breaking down the hydrogen bonds.

Question 5

Describe annealing

Answer 5

A primer is applied to the two separated DNA strands to allow for the Taq polymerase to start working. The temperature is cooled to 50-60 degrees Celsius, to help the primer bind to the DNA. The primer is an attachment that signals to the polymerase where to start synthesising new DNA.

Question 6

Describe elongation.

Answer 6

Temperature goes up to 72 degrees. Two polymerase molecules attach to the two primers on the two DNA strands and move along them. As they move along, they create new DNA by adding the complimentary nucleotides.

Question 7

What is DNA sequencing?

Answer 7

The determination of the promise order of nucleotides in a sample of DNA. It can be used to show whether a person will develop an inheritable disease, by comparing sequences.

Question 8

Describe Sanger Method

Answer 8

A form of DNA sequence in which four test tubes have dideoxyides (A, T, G and C), nucleotides and materials involved in PCR and gel electrophoresis. Dideoxides act as terminators, stopping extra nucleotides from being added. Different lengths of DNA are generated, which can be separated by gel electrophoresis.

Question 9

What are genetic probes?

Answer 9

DNA/RNA labelled with radioactive isotopes or fluorescent markers are used to detect a specific sequence of bases in another molecule, thus mutations causing a disease can be detected.

Question 10

How are mutations detected by genetic probes?

Answer 10

Identification of abnormal genes is achieved by mixing the gene probe with a piece of the DNA being investigated. As the probe is a single strand, it binds to a complementary base and targets the gene. If the gene is abnormal, the probe will not bind and a gap in the DNA will result. This shows during gel electrophoresis.

Question 11

What is a transgenic organism?

Answer 11

Organisms whose genome has already been altered by the transfer of a gene from another organism.

Question 12

What is a recognition site?

Answer 12

A specific sequence of nucleotides at which an enzyme cuts a strand of DNA.

Question 13

What is a restriction enzyme?

Answer 13

An enzyme that cuts a strand of DNA at a specific sequence of nucleotides.

Question 14

What is a phage?

Answer 14

A virus that infects bacteria.

Question 15

What is a plasmid?

Answer 15

A small circular strand of DNA distinct from the main bacterial genome, it is compared of only a few genes and is able to replicate independently within a cell. It encodes for certain traits that affect how bacteria look, act or survive.

Question 16

What is a vector?

Answer 16

A bacterial plasmid, viral phage or other such agent used to transfer genetic material from one cell to another.

Question 17

Explain how recombinant DNA works.

Answer 17

The gene needed to make copies is extracted using a restriction enzyme. Then a bacterial plasmid is cut open to allow for the gene to be inserted. The plasmid, along with enzyme, water and buffers are left in a test tube to allow other plasmids to be cut. The genes are then added along with DNA ligase. The plasmids are then inserted into a bacteria to reproduce.

Question 18

How does recombinant DNA help with insulin production?

Answer 18

The human gene that has the code for insulin production was introduced into bacterial cells using recombinant DNA. These bacteria became insulin factories and are cultured in vats. Now the insulin produced by the bacteria is identical to human insulin. It produces no side effects.

Question 19

How does recombinant DNA help with human growth hormone production?

Answer 19

Recombinant DNA has resulted in the production of GH for dairy cattle. mAdministration of the hormone has increased milk production, and research so far indicates that drinking milk from treated cattle does not pose a risk to human health.

Question 20

How has recombinant DNA technology helped treatment of Haemophilia A?

Answer 20

Injections of factor VIII concentrates have been used. These were collected through donors. Recombinant DNA overcame the risk of viral infections as factor VIII was produced in a way that is free of plasma proteins that could cause an immune response.

Question 21

Describe the process of Gel electrophoresis.

Answer 21

DNA samples are loaded into wells at the negative terminal cathode. An electrical current is applied. The molecules are pulled through the gel from the cathode to the positive terminal anode. The larger molecules move slower (found near top) and the smaller molecules move faster (found near bottom).