manipulating genomes Flashcards
DNA sequencing definition
working out the sequence of bases
Explain how DNA sequencing allows the sequence of amino acids in a polypeptide to be
predicted
- identify the order of bases
- code for one amino acid
Outline how to use DNA sequencing and bioinformatics to increase effectiveness of vaccination of X disease
DNA sequencing
- many strains
- predict the antigen
- make sure vaccine contains that antigen
Bioinformatics
- access large amounts of data
- identify the source of disease outbreak
Suggest how the interdisciplinary field of bioinformatics may be useful in determining whether a
newly-sequenced allele causes a genetic disease
- base sequence of gene is already known
- use computational analysis to make rapid comparisons of new gene sequence
The West Highland Terrier develops CPF more often than other breeds of dog
Explain how the high occurrence of CPF in West Highland Terriers could have been a result of
artificial selection
- inbreeding
- reduces genetic variation
- increased susceptibility for CPF
Explain how DNA sequencing could help scientists understand how the West Highland Terrier’s
genes affect its probability of developing CPF
- identify the sequence of bases that code for the amino acid for CPF
- compare genomes of different dog breeds
Explain why a booster vaccination is needed
- the conc. of memory cells decrease
Explain why only selected sections of non-coding DNA are used when profiling a human
- genome is most people are similar
- using the coding sequence does not create unique profiles
- non-coding DNA has a variable n.o of short tandem repeats
Why can you not be able to accurately calculate the n.o of DNA fragments in PCR?
- primers fail to anneal
- temp damages the DNA strand completely
iv. State the name of the enzyme used in PCR to synthesise new DNA strands
Taq polymerase
In electrophoresis, what does the buffer solution do?
- carry the charge to separate the fragments
Modern PCR technique uses DNA polymerase from the bacterium Thermus aquaticus. Why is this enzyme chosen?
- denatures at high temperatures
- the PCR can cycle continuously without stopping
Describe how DNA can be visualised after electrophoresis has been completed
- UV light
- fluorescent labelled bases
Suggest why proteins are heated before being placed in the electrophoresis gel
- denature protein
- expose charges
What technique would you plan to use, to compare digested and amplified fragments from the two DNA samples
electrophoresis
‘Genetically modified plants and animals should be classed as new species’.
Outline one experiment or investigation that would provide evidence to support or contradict the
statement
- compare DNA using electrophoresis
- if they same pattern = same species
3 differences between TLC and electrophoresis
TLC - separates via solubility
E - via size
E - uses electricity
TLC - x
TLC - dyes
E - fluorescent labelled bases
Scientists carry out gene silencing by inserting small sequences of RNA into potato cells. These RNA
sequences are complementary to mRNA from genes responsible for bruising.
Use this information to suggest why the technique is called ‘gene silencing’
- base sequence is unchanged
- mRNA is inhibited therefore translcation doesnt occur
- gene is not expressed
What needs to be done with the mRNA in order for the rest of the genetic modification to be
completed?
DNA to cDNA using reverse transriptionase
Suggest why there are very few ethical concerns about the genetic engineering of E. coli.
- safe
- few animal rights issues to consider
State one valid concern that people have about the genetic modification of bacteria.
- antibiotic resistance
3 differences between somatic and germ line therapy
S - mutation not passed onto offspring
- only affects parts of body cells
- short term
G - does pass on
- sex cells
- long term
Explain how inserting a new gene into a chromosome could affect the functioning of other
genes in that chromosome.
Insertion causes a frameshift mutation and changes the triple sequence
