Unit 3.5.8 - Gene Technology Flashcards
(111 cards)
1
Q
How is DNA base sequencing carried out nowadays?
A
Done together in one tube in an automated base sequencer. The tube contains all the modified nucleotides each with a different coloured fluorescent label.
2
Q
What does gene therapy involve?
A
Altering the defective genes inside cells to treat genetic disorders and cancer.
3
Q
Name the three main uses of transformed organisms?
A
- Agriculture
- Industry
- Medicine.
4
Q
What three things can be genetically engineered to benefit humans.
A
- Micro organisms
- Plants
- Animals
5
Q
What is the name of the two different techniques you can use for gene cloning?
A
Invitro and Invivo cloning
6
Q
How can restriction mapping be used to work out if a piece of DNA contains your added DNA fragment.
A
It will produce a different restriction map.
7
Q
How does the amount of DNA change for one cycle of PCR?
A
It doubles.
8
Q
What DNA do you look at if you want to trace only the female line of descent?
A
Mitochondrial DNA
9
Q
What is meant by not all of an organisms genome codes for proteins?
A
Some of the genome consists of repetitive, non coding sequences.
10
Q
What is gene cloning?
A
It is where you make identical copies of a gene.
11
Q
What are two advantages of using transformed organisms in medicine?
A
1, Many drugs and vaccines are produced by transformed organisms using recombinant DNA technology.
2. Drugs made using recombinant DNA technology can be produced quickly, cheaply and in large quantities. This can make them more affordable and so make them more available to people.
12
Q
What is an disadvantage of using transformed organisms in industry.
A
Some people are worried that the process used to purify proteins could lead to the introduction of toxins into the food industry.
13
Q
What are two ethical issues surrounding gene cloning?
A
- could be used in other ways other than medical treatment - treating the cosmetic effects of aging.
- People worry that it can do more harm than good - risk of over expression or it going wrong.
14
Q
How is electrophoresis carried out in four steps?
A
- DNA fragments are injected into wells of the gel and covered with a buffer solution that conducts electricity.
- An electric current is applied along the gel.
- DNA is negatively charged so attracted to the positive end of the gel.
4 Short fragments move faster than longer fragments and so they are separated according to length.
15
Q
How can you use genetic fingerprinting in genetic science?
A
You can compare sample of DNA collected from crime scenes to DNA from possible suspects to link them to the crime.
16
Q
What method can be used to make transformed micro organisms?
A
Invivo cloning.
17
Q
Why do more people suffer from sickle cell anaemia where malaria is more common?
A
Carriers are partially protected meaning they are more likely to survive so there is an increase frequency of the sickle call allele in the areas where malaria is common which increases the likelihood of someone carrying two copies of the allele and so there will be more sufferers.
18
Q
What are four advantages of invivo cloning?
A
- It can produce mRNA and protein as well as DNA because it is done in the living cell.
- It can produce modified RNA, modified mRNA or modified proteins.
- Larger fragments of DNA can be cloned.
- Relatively cheap method.
19
Q
How do you identify transformed cell?
A
Host cells are grown on agar plates and each cell divides and replicates its DNA creating a colony of cloned cells. Transformed cells will produce colonies where all the cells contain the cloned gene and the marker gene so you can use the marker gene to identify the transformed cells.
20
Q
What is genetic engineering also known as?
A
Recombinant DNA technology.
21
Q
What is the place called that restrictive endonuclease cuts the DNA at?
A
Recognition site.
22
Q
What is recombinant DNA?
A
DNA made by joining together DNA from different sources.
23
Q
What does a band at the same location during genetic fingerprinting show?
A
The same number of nucleotides in the fragment.
24
Q
What are the two different types of screening you can do using DNA probes?
A
Screening for single genes and screening for multiple genes.
25
What are four advantages of gene therapy?
1, Prolong the life of people with life threatening disorders and cancer.
2. Give people with genetic disorders and cancer a better quality of life by easing their symptoms.
3. Germ line therapy will allow the carriers of a genetic disorder to conceive a baby without the disease.
4. Germ Line therapy will also decrease the number of people that suffer from the genetic disorder or cancer.
26
What is a primer?
A short piece of DNA that is complimentary to the bases at the start of the fragment you want to copy.
27
Name five uses of genetic fingerprinting.
1. Determine genetic relationships
2. Determine genetic variability within a population.
3. Forensic Science
4. Medical diagnosis
5. Animal and Plant breeding.
28
How can you make transformed animals?
By inserting the gene that codes for a desirable characteristic into an animal embryo.
29
What are antiglobalisation activists against?
Large bio technology companies who control the use of genetic engineering becoming bigger and more powerful.
30
What is invivo cloning?
Where the gene copies are made within a living organism, as the organism grows and divides it replicates it's DNA creating multiple copies of the gene.
31
What are the two types of gene therapy?
Somatic therapy and germ line therapy.
32
How do you read the DNA base sequence from the gel produced at the end of the chain termination method?
Read the bands from the bottom up, each band represents one more base you have added.
33
What is the advantageous effect of sickle cell anaemia?
The carriers are partially protected from malaria.
34
How do you make a DNA probe to screen for clinically important genes?
The gene you want to screen is sequenced. PCR is then used to make multiple copies of part of the gene and these are the probes.
35
What are the host cells during invivo cloning?
Bacteria cells
36
When are marker genes inserted into the vectors?
At the same time as the gene to be cloned.
37
What is a DNA microarray?
A glass slide with microscopic spots of different DNA probes attached to it.
38
Which method of gene therapy you use depends on?
Whether the disorder is caused by a mutated dominant allele or two mutated recessive alleles.
39
What are six disadvantages of gene therapy?
1. The body could identify the vector as foreign bodies and start an immune response against them.
2. An allele could be inserted into the wrong place in the DNA causing more problems.
3. An inserted allele could be over expressed producing too much of a missing protein.
4. Disorders caused by multiple genes will be difficult to treat with this technique.
5. Somatic therapy may have a short term effect
6. People may have to undergo multiple treatments with somatic therapy.
40
If a gene is too long to be sequenced what can you use first to make smaller fragments?
Restriction mapping
41
What are the three ways that DNA fragments can be produced?
Reverse transcriptase, Restriction endonuclease and PCR.
42
How many primers do you need for one cycle of PCR and why?
Two , one for each strand.
43
Why can gene technologies now be done on a larger scale?
The techniques are often automated and more cost effective.
44
What is the two main uses of genetic screening in medicine?
Diagnosing genetic disorders and deciding treatment options.
45
How can an antibiotic gene act as a marker gene?
If the host cells are grown on agar plates containing the specific antibiotic, only transformed cells which have the marker gene will survive and grow.
46
What is a vector DNA?
Something that is used to transfer DNA into a cell.
47
What is invitro cloning?
Where the gene copies are made outside of a living organism using PCR.
48
What enzyme can be used to join the sticky ends of two fragments together if the sequences are complimentary?
DNA ligase
49
What does reverse transcriptase do?
Makes cDNA that is complimentary to the mRNA sample.
50
What does restriction endonuclease do?
It is an enzyme that recognises specific palindromic sequences and cuts the DNA at these places leaving sticky end.
51
How can genetic fingerprinting prevent animals and plants inbreeding?
You can identify the least related individuals in a population and breed them together.
52
What are the four steps in the chain termination method that lets you sequence small fragments of DNA?
1. A mixture of the following is added to the four separate tubes: single stranded DNA template, DNA polymerase, DNA primers and Free nucleotides and a fluorescently labelled modified nucleotide.
2. The tubes undergo PCR which produces many strands of DNA, that are of different lengths because each one has been terminated at a certain point.
3. DNA fragments are separated by electrophoresis are placed under UV light.
4. You can then read the complimentary base sequence from the gel.
53
Why is it easier to find mRNA molecules complimentary to the gene you want than it is to find the gene?
Many cells only contain two copies of each gene so it makes it difficult to obtain the DNA fragment containing the target gene however there are many mRNA molecules complimenary to the gene so mRNA is easier to obtain.
54
How can you use genetic fingerprinting in medical diagnosis?
Genetic fingerprinting can look at the unique pattern of several alleles and can be used to diagnose genetic disorders and cancer.
55
Give an example where a mutated gene is useful.
Sickle Cell anaemia.
56
How can genetic fingerprinting be used to determine genetic relationships?
The more bands that match the more closely related two people are.
57
What is somatic therapy?
Altering the alleles in the body's cells that are most affected by the disorder.
58
What can mutated genes cause?
Cancer, genetic disorders or they sometimes can be useful.
59
What are four advantages of invitro cloning?
1. It can produce lots of DNA
2. The DNA produced isn't modified
3. The technique only replicates the DNA fragment of interest meaning you don't have to isolate the DNA fragment
4. It is a very fast process and can be used to produce millions of copies of DNA.
60
What does inbreeding cause?
It decreases the gene pool which can lea to an increased risk of genetic disorders leading to health problems.
61
What are the three main steps in invivo cloning?
1. Making recombinate DNA
2. Transforming cells
3. Identifying transformed cells.
62
What are the four steps in how DNA probes can be used to locate a gene?
1. A sample of DNA is digested into fragments using restriction enzymes and separated using electrophoresis.
2. The separated DNA fragments are transferred to a nylon membrane and incubated with a fluorescently labelled DNA probe.
3. This means if the gene is present DNA will hybridise to the target gene.
4. The membrane is then exposed to the UV light and the location of the gene is shown by a fluorescent band.
63
What are the six steps in PCR?
1. A reaction mixture is set up of the DNA sample, free nucleotides, primers and DNA polymerase.
2. The DNA mixture is heated to 95 degs to break the hydrogen bonds between the two strands of DNA
3. The mixture is then cooled to around 50 - 65 degs so the primers can anneal to the strands.
4. The reaction mixture is heated to 72 degs so DNA polymerase can work.
5. DNA polymerase lines up free nucleotides alongside the template strand and specific base pairing means new complimentary strands are formed.
6. Two copies of the fragment DNA are formed.
64
What is an advantage of using transformed organisms in industry.
Industrial processes often use biological catalysts, they can be produced from transformed organisms in large quantities for less money reducing costs.
65
What is reverse transcriptase the opposite to?
Transcription
66
What is germ line therapy?
Altering the alleles in the sex cells so that every cell of any offspring produced from these cells will be affected by the gene therapy and wont suffer from the disease.
67
What is gene technology?
All the techniques that can be used to study and alter genes and their functions?
68
What can you compare from two different people to identify them and why?
The number of times a sequence is repeated at different loci in a genome because the probability of two individuals having the same number of repeats at each locus is very low.
69
What is sickle cell anaemia?
A recessive disorder caused by mutation in the haemoglobin gene, this makes the red blood cells sickle shaped which blocks capillaries and restricts blood flow causing organ damage and periods of acute pain.
70
Why can fluorescent act as a marker gene?
When the agar plate is placed under UV light only transformed cells will fluoresce.
71
What DNA do you look if you want to trace only the male line of descent?
DNA on the Y chromosome.
72
What are the three steps in how recombinant DNA made?
1. The vector's DNA is isolated and then cut open using the same restriction endonuclease that was used to isolate the DNA fragment containing the target gene.
2. DNA ligase is used to stick the sticky ends of the DNA fragment and the vector DNA together.
3. The new combination of bases in the DNA is called recombinant DNA.
73
What does genetic screening mean?
Analysing a person's DNA to see whether they have any mutations.
74
Does somatic therapy affect the sex cells?
No
75
What are two disadvantages of using transformed crops in agriculture.
1. Mono culture this could make the whole crop vulnerable to disease because the plants are genetically identical it also reduces biodiversity.
2. If transformed crops interbreed with wild plants it can spread the recombinant DNA and lead to the formation of superweeds.
76
What are two disadvantages of using transformed organisms in medicine?
1. Companies who own genetic engineering technology may limit the use of technologies that could be saving lives.
2. People worry that the technology could be used unethically to create designer babies.
77
What does diagnosis and genetic counselling involve?
Advising patients and their relatives about genetic disorders, advising them about screening and explaining the results of screening.
78
How does gene therapy work is the disorder is caused by a mutated dominant allele?
You can silence the dominant allele by sticking a bit of DNA in the middle so it doesn't work anymore.
79
What are three disadvantages of invivo cloning?
1. The DNA fragment has to be isolated from other cell components.
2. You may not want modified DNA
3. It can be quite a slow process as sometimes the bacteria can grow quite slowly.
80
What are organisms that have had their DNA altered by genetic engineering called?
Transformed organisms.
81
In four steps how are DNA probes used to screen for multiple genes?
1. The probe is used is part of the DNA microarray
2. a sample of human DNA with fluorescent tags is washed over the array.
3. If it contains any complimentary DNA sequences to the probes it will stick to the array.
4. You then place it under a UV light and any spot that fluoresces means the person's DNA contains that specific gene.
82
What are three disadvantages of invitro cloning?
1. Only replicates a small amount of DNA
2. You may want modified RNA, modified mRNA or modified protein.
3. Can be expensive if you want to produce a lot of DNA.
83
Name three advantages of transformed organisms being used in agriculture.
1. Crops can be transformed so they give higher yields and more nutrition - this means the plant can reduce the risk of famine and malnutrition.
2. Crops can be transformed to have resistance to pests so you need fewer pesticides which reduces cost and any environmental problems associated with using chemicals.
3 Crops can be transformed to be resistant to droughts so they can survive with little water
84
How can you use genetic fingerprinting to determine genetic variability within a population?
The greater the number of bands that don't match the more genetically different people are, this means you can compare the number of repeats in several places in the genome of the population to find out how genetically varied the population is.
85
What are DNA probes?
Short, single strands of DNA that have a specific base sequence that is complimentary to the base sequence of part of the target gene. They have a label attached so that they can be located (same as a marker gene).
86
What are the two main uses of DNA probes?
Used to locate genes or see if a person's DNA contains a mutated gene.
87
Give two examples of vectors?
Plasmids or Bacteriophages
88
How does restriction mapping come at the end of base sequencing?
You cut the DNA by using restriction enzymes so you can stick all the chunks back together in the right order by looking at the restriction map.
89
How are some of the nucleotides modified in the chain termination method?
Once it has been added no more bases are added after it.
90
What does PCR stand for?
Polymerase Chain Reaction
91
What is meant by palindromic sequence?
One that is read the same in opposite directions.
92
What is the main use of PCR?
Do make millions of copies of a fragment of DNA
93
What is another use of restriction mapping?
To work out if a piece of vector DNA contains your added DNA fragment.
94
When does the sickle cell anaemia gene become useful?
If you are just a carrier.
95
What gene is added to identify the transformed cells.
Marker genes
96
Give two examples of marker genes?
Antibiotic resistant gene and fluorescent
97
What is genetic engineering?
The manipulation of an organsims DNA.
98
How is genetic fingerprinting carried out in four steps?
1. Cells are broken down to release DNA and then amplified by PCR.
2. The DNA is cut into fragments using restriction enzymes.
3. The fragments are separated out on basis of size using a process called gel electrophoresis.
4. A Radioactive material is added which combines with the DNA fragments and a photographic copy of the DNA bands is obtained on xray film.
99
What is ligation?
It is when DNA ligase is used to stick the sticky ends of two DNA fragments together.
100
What is a sticky end?
Small tails of unpaired bases at the end of each fragment.
101
Why do different restriction endonucleases cut DNA at different recognition sites?
The shape of the recognition sequence is complimentary to the enzymes active site.
102
What are the four steps for restriction mapping?
1. Different restriction endonuclease enzymes are used to cut labelled DNA fragments.
2. DNA fragments are then separated by electrophoresis.
3. The length of the fragments produced are used to determine the relative locations of the cut sites.
4. Once these are know the restriction map of the DNA can be made.
103
What are the benefits of carrying out DNA base sequencing in an automated base sequencer?
It allows whole genomes to be sequenced for relatively little money and time.
104
How do you make cDNA using reverse transcriptase?
mRNA is isolated from cells then it is mixed with DNA nucleotides and reverse transcriptase and the reverse transcriptase makes the DNA.
105
How do you transform cells during invivo cloning?
The vector with the recombinant DNA is used to transfer the gene into host cells, if the cells take up vectors contain the gene they are said to be transformed.
106
How does gene therapy work is the disorder is caused by two mutated recessive alleles?
Add a working dominant to supplement the faulty ones.
107
Why is genetic screening used to decide treatment options?
Different mutations cause different cancers which respond to treatments in different ways so it helps you to choose the best course of treatment.
108
What does cDNA stand for?
Complimentary DNA
109
What can DNA base sequencing be used for?
To determine the order of bases in a section of DNA.
110
What is the name of the method used in DNA base sequencing?
Chain termination method.
111
How can transformed plants be made?
By inserting the gene that codes for a desirable characteristic into a plasmid. The plasmid is then added to the bacterium and the bacterium is used as a vector to get the gene into the plant cells.
