DNA technology Flashcards

Question

Explain how the enzyme marker lactase can be used to identify transformed cells.

Answer 1

the enzyme lactase can turn a certain substance blue from colourless. The gene for this enzyme is inserted into the plasmid. The DNA fragment is inserted in the middle of the gene to disrupt it. The bacteria are then grown on the agar plate with the colourless substance. The colonies which cannot turn the colourless substance blue contain the recombinant plasmid

Answer 2

an industrial fermenter

Answer 3

a fermenter is used to grow multiple copies of the host cell which have been identified as containing the recombinant plasmid. This large cloned population of the host cell can then produce the protein coded for by the inserted DNA fragment

Answer 4

inside of a living organism

Answer 5

to prevent contamination of the culture by harmful bacteria

Answer 6

to be used for respiratory substrate

Answer 7

for aerobic respiration of the bacteria

Answer 8

Polymerisation Chain Reaction

Answer 9

Isolation of a gene Insertion into vector (usually plasmid) Transformation into host cells (plasmid put back into bacteria) Identification that it has been taken up Growth

Answer 10

in-vitro cloning

Answer 11

outside of a living organism

Answer 12

thermocycler DNA fragment to be amplified DNA polymerase-taq polymerase primers DNA nucleotides

Answer 13

The sample of fragment DNA is mixed with the DNA nucleotides, primers and DNA polymerase in a test tube. The test tube is then placed in a PCR machine (thermocycler) The mixture is heated to between 94-96 degrees The hydrogen bonds between the complimentary base pairs break, leaving two single strands of DNA The mixture is cooled to 50-60 degrees Celsius At this temperature, the primers will join to template strands by complimentary base pairing at the 5' end-this is called annealing. Primers are needed as DNA polymerase involved in the next step has to attach to one of them. The temperature is increased to 72 degrees Celsius. Taq polymerase binds to the small section of double stranded DNA (the primer) and synthesises new strands. Taq polymerase catalyses condensation reactions which join the complimentary DNA nucleotide bases and the single strand DNA by hydrogen bonds and adjacent nucleotides by phosphodiester bonds

Answer 14

quick any sequence can be made high accuracy no introns

Answer 15

it used to amplify the DNA fragments in a short period of time

Answer 16

-DNA sequencing. - Gene cloning. - DNA profiling. - Making artificial genes.

Answer 17

To produce large quantities of 'cloned' DNA from a very small sample

Answer 18

it is very stable at high temperatures, does not denature

Answer 19

it would be amplified along with the intended DNA sample, contaminating the sample and rendering it as unusable

Answer 20

dirty equipment that has DNA molecules left on it from previous treatments viruses and bacteria in the air DNA from technician

Answer 21

using disposable equipment use of sterile procedures

Answer 22

nucleotides and primers used up. DNA polymerase denatures.

Answer 23

PCR copies DNA that has been partly broken down/ doesn't require living cells useful in forensic science Rapid-billions of copies in a short period of time. PCR is very sensitive. Minute amounts of DNA, such as that contained in a single cell can be copied DNA embedded in other material can be copied. Useful for analysing DNA in archaeological remains cloned genes produced in solution. They cannot be used directly to manufacture the protein that they encode. DNA polymerase will only copy a gene if it is marked at each end by complimentary primers. If we do not know the base sequences at each end of the gene, we cannot make appropriate primers. Cannot be used to copy genes that have not been studied before. PCR unreliable if DNA fragments longer than about 1000 base pairs lack of error-correcting mechanisms, so the error rate is higher.

Answer 24

partly broken down DNA not copied Used for introducing genes into other organisms unlikely to be contaminated In vivo methods are less sensitive, so large amounts of sample DNA are needed. Less useful in forensic work. Unless DNA can be isolated from the medium in which it is embedded, it cannot be copied. cloned genes already inside cells that will manufacture the protein that they encode once incorporated into its host DNA, the gene will be copied by the host cell This method can be used to copy genes that have not been studied before. methods reliably copy genes up to about 2mbp long- precise cells have mechanisms for correcting any errors that are made when copying genes therefore its accurate.

Answer 25

The sequence of amino acids and bases is determined for the required gene. The desired sequence of nucleotide bases for the gene is inputted into a computer The sequence is checked for biosafety and biosecurity to ensure it meets international standards as well as various ethical requirements. The computer designs a series of small overlapping single strands of nucleotides, called oligonucleotides The oligonucleotides are linked together- no introns have been copied The gene is replicated using PCR to make multiple copies.

Answer 26

Quick any sequence can be made high accuracy no introns

Answer 27

Blunt ends

Answer 28

Sticky ends