Gene Technology

Question 1

What is a Palindromic site?

Answer 1

its read the same forwards and backwards

eg) CTTAAG to GAATTC

Question 2

What is the role of restriction enzymes?

Answer 2

They cut DNA at specific Palindromic sites called restriction sites

Question 3

What does using a restriction enzyme leave DNA with?

Answer 3

sticky ends (unpaired bases)

Question 4

What does reverse transcriptase do?

Answer 4

mRNA ——-> cDNA

Question 5

What does cDNA not have?

Answer 5

introns (made from mRNA post splicing)

Question 6

What enzyme does DNA ——> mRNA?

Answer 6

RNA Polymerase

Question 7

Describe Artificial Synthesis of a gene.

Answer 7

use a gene machine to make DNA from scratch, making oligonucleotides, join theses together to make a synthetic gene.

Question 8

What is an oligonucleotide?

Answer 8

a sequence of around 25 nucleotides

Question 9

What are the three ways we can isolate target genes?

Answer 9

gene machine, reverse transcriptase or restriction enzymes

Question 10

What is PCR used for?

Answer 10

to amplify a gene

Question 11

What are the 4 components of PCR?

Answer 11

DNA sample, free nucleotides, primers, DNA polymerase

Question 12

describe the 3 steps of PCR

Answer 12

heat up to 95 degrees
cool to 50 degrees
heat to 70 degrees

Question 13

Why do we heat the sample to 95 degrees

Answer 13

break the H+ bonds between so they are single stranded

Question 14

Why do we cool the sample to 50 degrees

Answer 14

allows the primer to attach by complementary base pairing to the exposed strand - making a double strand - so DNA polymerase can bind to the double stranded section

Question 15

Why do we heat the sample back up to 70 degrees

Answer 15

there is a higher kinetic energy increasing enzyme action

Question 16

why can the DNA polymerase work at high temperatures?

Answer 16

extracted from thermophillic bacteria

Question 17

What is a primer?

Answer 17

Short sequence of DNA which is complementary to the target DNA

Question 18

Name three ways we can isolate a target gene

Answer 18

restriction enzymes, Gene machine, reverse transcriptase

Question 19

What charge is DNA?

Answer 19

negative

Question 20

Describe the process of electrophoresis

Answer 20

attach a fluorescent label to DNA
put labelled DNA fragments into the well at the negative end
turn on current
DNA is attracted to the positive electrode

Question 21

How can we distinguish the length of DNA from electrophoresis?

Answer 21

smaller fragments move faster (therefore further over any given time)

Question 22

How can you calibrate the scale in electrophoresis?

Answer 22

use pieces of DNA of a known length

Question 23

How can we insert the isolated target gene into a vector?

Answer 23

use the same restriction enzyme so that the sticky ends are complementary
DNA ligase makes recombinant DNA

Question 24

How can the vector be inserted into the plasmid?

Answer 24

ice cold calcium chloride and a heat shock to make a transgenic/ transformed organism

Question 25

How can scientists identify transformed/transgenic organisms?

Answer 25

marker genes, fluorescence, antibiotic resistance

Question 26

Why do we then culture the transformed/ transgenic organism (bacteria)

Answer 26

the organism transforms/ translates the recombinant DNA | to make desired protein eg) insulin

Question 27

What is gene therapy?

Answer 27

altering faulty alleles that cause genetic disease

Question 28

How can we silence a genetic disorder caused by a dominant allele? (eg) Huntingtons)

Answer 28

sufferer is heterozygous use a vector to add a DNA fragment into dominant allele this prevents transcription recessive allele expressed

Question 29

How can we silence a recessive allele disease (eg) cystic fibrosis)

Answer 29

sufferer is homozygous use a vector to add the functional allele to DNA dominant allele will be expressed

Question 30

What is Germ line gene therapy?

Answer 30

Change to the alleles of Gametes (currently illegal)

Question 31

What is Somatic gene therapy?

Answer 31

Changing the alleles of body cells so offspring don't inherit

Question 32

Identify 4 possible problems with Gene therapy

Answer 32

alleles inserted into wrong locus could silence the wrong gene eg) tumour suppressor gene could be over expressed use of gene therapy for cosmetics

Question 33

identify one use of Transformed organisms in agriculture

Answer 33

express a protein from bacteria which is toxic to pests

Question 34

advantages of genetically modifying (transforming crops to be toxic to pests

Answer 34

less chemical pesticide used, more efficient, lose less energy

Question 35

disadvantages of genetically modifying (transforming crops to be toxic to pests

Answer 35

monoculture, low genetic/bio diversity,

Question 36

How can genetic modification be used in Industry?

Answer 36

to make enzymes eg)renin (cheese) and lipases (clothes wash)

Question 37

what are the advantages of making genetically modified enzymes in industry?

Answer 37

reduce energy, cost, fast, cheap

Question 38

How can genetic modification be used in research?

Answer 38

make transformed pathogens to treat disease

Question 39

ads of transformed pathogens in research

Answer 39

treat disease, pathogens will not develop resistance, reduce suffering

Question 40

disads of transformed pathogens in research

Answer 40

could mutate and infect humans, used as bioweapons

Question 41

how can genetic modification be used in Pharming/medicine?

Answer 41

transform bacteria to express proteins, mammals can be transformed to produce useful products in milk

Question 42

ads of genetic modification be used in Pharming/medicine

Answer 42

cheaper than making proteins synthetically

Question 43

disads of genetic modification be used in Pharming/medicine

Answer 43

possible unexpected side affects eg) cancer | using animals as commodities

Question 44

What is a DNA probe?

Answer 44

a short sequence of single stranded DNA with a label attached, that is complementary to a specific allele or gene

Question 45

Describe the process of using a DNA probe

Answer 45

attach label to the DNA probe If complementary DNA is present the probe will hybridise to it rinse to remove hybridised DNA probes View labels to establish is DNA is present

Question 46

Describe the use of a DNA Microarray

Answer 46

label is attached to the patient DNA can test multiple alleles/ mutations at once many probes are attached to a tile in a grid DNA will hybridise by complementary H+ bonding rinse

Question 47

How is Genetic Counselling used?

Answer 47

Healthcare professionals can advise patients about risks involving heritable disease, and risk of developing genetic diseases later in life eg) BRCA 1 gene and breast cancer Genetic Counselling allows patients to make informed decisions about actions to take

Question 48

How is Genetic Screening used?

Answer 48

parents see is they are carriers of recessive alleles, can also be used to diagnose and treat genetic diseases before symptoms show eg) babies and CF

Question 49

How can DNA probes be used to give personalised medicine?

Answer 49

If a doctor is aware of genotype can give most effective drug, or drug least likely to cause side affects

Question 50

What is genetic fingerprinting?

Answer 50

Identifying individuals by comparing differences in their Variable Number Tandem Repeats (VNTRs)

Question 51

where are VNTRs located?

Answer 51

non - coding DNA?

Question 52

Why do we use VNTRs to identify criminals in forensic investigation?

Answer 52

they don't affect phenotype, so vary far more between individuals

Question 53

Describe the forensic process in identifying suspects

Answer 53

collect samples of DNA from crime scene and suspects amplify using PCR run using gel electrophoresis compare the results of suspects with the crime scene DNA

Question 54

what else can genetic fingerprinting be used for?

Answer 54

paternity tests, establishing relatedness (used in conservation of endangered species)