Gene technology Flashcards
Gene definition
DNA base sequence which codes for either the amino acid sequence of a polypeptide or a functional RNA
Genome definition
All the DNA in a cell
Proteome definition
The range of proteins a cell can make
Intron definition
Non-coding DNA WITHIN a gene
Non-coding multiple repeats definition
Non-coding DNA BETWEEN genes
What kind of DNA is the DNA of chloroplasts and mitochondria the same as?
Prokaryotic
What do genome projects determine?
The DNA base sequence of an organism’s genome
How can genome projects be used to determine an organism’s proteome?
Allow the amino acid sequence of a protein to be determined
Why is it easier to determine the proteome of prokaryotic DNA?
No introns, shorter so faster
How can genome projects be used in medical research?
Can identify the antigens of microorganisms for use in vaccine production
What 2 features in eukaryotes makes it difficult to translate the genome into the proteome?
Non-coding DNA and regulatory genes
How is a DNA base sequence determined?
Chain termination sequencing
What 4 components are needed in chain termination sequencing?
- Sample of DNA
- 4 normal DNA nucleotides
- DNA polymerase
- Primer
What is added in chain termination sequencing that fluoresce a different colour?
Chain terminating nucleotides which can’t form a phosphodiester bond and so stop DNA replication
What are DNA fragments run on in chain termination sequencing?
Electrophoresis gel
Recombinant DNA definition
DNA made from 2 or more different species
What are the 3 methods of producing a DNA fragment in in vivo gene cloning?
- Reverse transcriptase
- Restriction enzymes
- Gene machine
What does reverse transcriptase do and how does this method produce a DNA fragment (3 steps)?
Forms DNA from mRNA
1. mRNA coding for (insulin) removed (from beta cells in human pancreas)
2. Reverse transcriptase makes cDNA from mRNA
3. DNA polymerase makes cDNA double-stranded
How do restriction enzymes produce a DNA fragment?
Hydrolyse phosphodiester bonds at recognition sites which forms sticky ends
Why is the gene machine more efficient in producing a DNA fragment than the other 2 methods?
- Very accurate
- Faster as no need to isolate DNA/RNA
- No introns so can be expressed by prokaryotes
- Any sequence of nucleotides can be made
What must be added to a DNA fragment before it is inserted?
Promoter and terminator
Vector definition
Carries the gene into the cell
How is a gene bound to a plasmid (3 steps)?
- Restriction enzymes cut open the plasmid
- Sticky ends of the plasmid are complementary to the sticky ends of the gene
- DNA ligase joins nucleotides of plasmid and inserted gene
How is a DNA fragment introduced to a host cell?
Heat shock makes the cell’s membrane more porous so the plasmid/gene can pass through more easily
What does a marker gene do?
Identifies which cells have taken up the plasmid/gene
How does an antibiotic resistance marker gene identify bacteria containing the plasmid?
Only cells containing the plasmid survive
Which process identifies which plasmids contain the recombinant DNA?
Replica plating (ampicillin, tetracycline, marker gene disruption etc.)