A2C2 - Chapter 11 - Application of Reproduction and Genetics Flashcards

(50 cards)

1
Q

What is the human genome project?

A

A group of scientists used sanger sequencing to successfully map the entire human genome.

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2
Q

What is DNA sequencing?

A

Identifying the base sequence of a DNA fragment.

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3
Q

What is sanger sequencing?

A

A method of DNA sequening in which requires relatively short sections of DNA at a time.
It takes ages tho.

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4
Q

Outline the potential benefits of the Human Genome Project.

A

Allows for development of targeted medicine with greater accuracy of diagnosis.

Early detection of disease.

Enables the study of whether mutation has occured of different genes.

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5
Q

What is the 100K genome project?

A

UK Govt project that aims to study variation in the human genome amongst 100,000 UK citizens.
This uses Next Generation Sequencers (NGS)

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6
Q

Describe next generation sequencing (ngs)

A

A faster, cheaper method of dna sequencing that only takes a few hours to map out an entire human genome.

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7
Q

Describe genetic counselling.

A

Service aiming to provide information and advice to those affected by or at risk of genetic disease.

Helps affected individuals or familes to make an informed decision.

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8
Q

What is genetic screening?

A

Testing individuals for faulty genes.

Used to detect disorders such as cystic fibrosis, huntington’s disease and haemophillia.

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9
Q

Outline potential disadvantages to genetic screening.

A

Screening for issues like cancer only shows an increased risk therefore can cause unneccesary stress and anxiety.

Risk of false positives or negatives.

Misuse of information/what if people like health insurance discriminates?

Who should actually be screened?

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10
Q

Give some examples of organisms other than humans which have been genetically screened.

A

Chimpanzees and other primates
Anopheles Gambiae (mosquito)
Plasomodium Parasite

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11
Q

How has sequencing Anopheles Gambiae been useful to humans?

A

The anopheles was able to have insecticide resistance

Hence, with the sequencing humans were able to produce insecticide that anopheles are susceptible to.

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12
Q

Outline the advantage of sequencing the genome of Plasmodium sp. to humans.

A

Plasmodium has developed drug resistance.

Enables drugs that are being developed to be more effective.

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13
Q

What is genetic fingerprinting?

A

A technique used to genetically identify an organism

Used in forensics, screening for hereditary disease, paternity testing, selection for clinical trials.

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14
Q

What are exons?

A

Region of DNA coding for amino acid sequence.

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15
Q

What are introns?

A

Non-coding regions of DNA.

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16
Q

What are STRs?

A

Short tandem repeats

Sections of repeated nucleotides in introns that produces variation in individuals.

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17
Q

What techniques can be used to produce a genetic fingerprint?

A

PCR
Gel electrophoresis

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18
Q

What is PCR?

A

Polymerase Chain Reaction

Used to amplify fragments of DNA.

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19
Q

Describe the reaction mixture in the first stage of PCR. (4)

A

Contains fragment to be amplified.

Primers that are complimentary to the start of the fragment.

Free nucleotides to match up to exposed bases.

Taq polymerase to create the new DNA.

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20
Q

What is Taq polymerase?

A

A thermally stable enzyme that synthesises a double stranded molecule of DNA from a single strand template strand using complimentary nucleotides.

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21
Q

Summarise the process of amplifying DNA fragments in PCR.

A

Heated (90C) to break hydrogen bonds between DNA strands.

Cooled (55C) to allow primers to bind (annealing)

Heated (70C) to activate Taq Polymerase and allow free nucleotides to join.

New DNA acts as a template for the next cycle.

22
Q

What is gel electrophoresis?

A

A technique that separates nucleic acid fragments or proteins by size via electric current.

23
Q

How does gel electrophoresis work?

A

DNA fragments of varying lengths are placed into one end agarose gel.

Electric current is applied. DNA fragments move towards the positive end of the gel.

Shorter fragments travel further. The pattern of bands created is unique to every individual.

24
Q

What is genetic engineering?

A

Modification of a genome of an organism by the insertion of a desired gene from another organism.
This enables the creation of organisms with desirable characteristics.

25
What is recombinant DNA?
A combination of DNA from two different organisms.
26
Summarise the process of using restriction enzymes to produce DNA fragments.
Gene identified using gene probe Restriction endonucleases cut the DNA at specific sequences producing sticky ends.
27
Summarise the process of using reverse transcriptase to produce DNA fragments.
mRNA is complementary to target gene (used as a template) Reverse transcriptase synthesises cDNA (complementary) Mixed with free nucleotides which match up their base pairs. DNA polymerase joins nucleotides forming the second strand.
28
Outline the advantages of using Reverse Transcriptase to produce cDNA.
Do not have to locate the gene. Gene is not cut into nonfunctional fragments by restriction enzymes. Introns not present in cDNA. Doesn't require post-transcriptional processing to produce mRNA.
29
Summarise the process of inserting a DNA fragment into a vector.
Plasmid (circular ring of DNA from bacteria) used as vector. Plasmid is cut using the same restriction enzymes as DNA to produce complimentary sticky ends. DNA ligase joins the fragment and plasmid together.
30
Describe how antibiotic resistance genes are used in the identification of recombinant bacteria.
Antibiotic resistance genes can be inserted into plasmids at the same time as DNA fragments. The transformed cells are then placed onto a plate with antibiotics. Only cells that took up the vector will grow.
31
Give an application for genetic modification of bacterial cells.
Human gene for insulin production can be inserted into the vector, so that the bacterial cell will produce insulin. Useful in medicine eg: treatment of diabetes.
32
Outline the disadvantages of using Recombinant DNA to make human products.
Identifying the required gene may be difficult. Some eukaryotic genes cannot be expressed in prokaryotic bacteria. Antibiotic resistance genes could be passed onto pathogenic bacteria. Expensive
33
What are GM organisms?
Organisms that have had their genome altered.
34
Outline the benefits of GM crop production.
Improves nutritional value of foods. Longer shelf life of products Greater crop yields Reduced need for pesticides
35
Outline the risks of GM crop production.
Reduction in biodiversity Unknown effects on health Cross pollination could result in herbicide resistant weeds May increase the cost for farmers Transferred gene may transfer into wild populations and cause problems.
36
What is gene therapy?
A therapeutic technique in which a faulty allele is replaced with a functional allele in order to prevent disease.
37
Name the two types of gene therapy.
Somatic Cell Therapy Germ Line Therapy
38
Differentiate between somatic cell therapy and germ line therapy.
Somatic = Allele is introduced to target cells only, it is short term and must be repeated. Germ Line Therapy = allele introduced to embryonic cells so it is in all resultant cells, this means it would be permanent and passed onto offspring.
39
What is a vector?
A carrier used to transfer a gene from one organism to another eg: plasmid or virus
40
What is Duchenne Muscular Dystrophy?
X-linked recessive gene Characterised by weaker muscles and muscle degeneration.
41
What is the cause of DMD?
Caused by one or more mutations in the Dystrophin gene that prevent the production of dystrophin.
42
Outline how DMD can be treated using gene therapy.
1. Heathly gene inserted into a vector 2. Vector inserted into muscle tissue 3. Virus delivers gene to muscle cells 4. New gene incorporated into DNA of cell. 5. Transcription and translation of gene produces normal dystrophin protein. 6. Symptoms of DMD alleviated.
43
What is drisapersen?
An experimental drug that aims to fix DMD via exon skipping.
44
Explain how Drisapersen works.
Introduces a molecular patch over the mutated exon, enabling the gene to be read. A shorter, more functional type of Dystrophin is then synthesised.
45
Discuss the ethical issues surrounding the use of gene therapy.
Is it right to alter the genotype of an unborn child? Health implications eg: immune response Could lead to healthcare inequalities Expensive - money could be used elsewhere
46
What are stem cells?
Cells that are undifferentiated and retain the ability to differentiate into a range of cell types.
47
What is tissue engineering?
An extension of gene therapy that aims to replace, repair or improve biological function by replacing organs and tissues.
48
What is the main advantage of using stem cells?
Rapid production of genetically identical cells and organisms.
49
Outline the disadvantage of stem cells.
Expensive and unreliable in mammals. In plants, disease and pathogens can cause issues. Inadvertent selection of disadvantageous alleles which could have unknown long-term effects.
50
What are the ethical issues surrounding the use of stem cells from embryos? (3)
Embryos are destroyed which is seen as unethical and a waste of potential human life. Could lead to the farming of embryos for stem cells (ie exploitation) May lead to reproductive cloning of humans