gene technologies Flashcards
(24 cards)
What is a vector?
- A vector is a carrier used to
transfer DNA into a host cell - Common vectors include:
→ Plasmids (circular DNA in bacteria)
→ Viruses
→ Liposomes
RNA
interference
- inhibition of the translation of
mRNA - the mRNA gets destroyed so it
cannot be translated - occurs in eukaryotes and some
prokaryotes
siRNA
- small interfering RNA
- siRNA binds to complementary
mRNA and causes enzymes to
degrade the mRNA, preventing
translation.
Recombinant
DNA technology
- combining different organisms’
DNA - enable scientists to manipulate
and alter genes to improve
industrial processes and
medical treatment
Sequencing
projects
- Reading the full genome of
organisms - provides opportunities to
screen DNA to identify potential
medical problems
How can you
create a DNA
fragment?
- Reverse transcription with
reverse transcriptase - restriction endonucleases
- gene machine
Gene machine
creates DNA fragments using a
computerised machine
Reverse
transcriptase
- An enzyme that makes single-
stranded complementary DNA
(cDNA) from an mRNA template
Restriction
endonucleases
- Enzymes that cut up DNA to
create fragments - cut at specific
recognition/restriction
sequences - results in sticky ends
In vivo cloning
- Involves inserting DNA fragments into vectors (e.g. plasmids), which are
introduced into host cells. - involves restriction endonucleases
enzymes
In vitro cloning
Using PCR to create a large
number of identical copies of a
DNA fragment
Uses of PCR
- Used widely in gene technology
to make large numbers of
copies of DNA fragments - e.g. forensics, genotyping,
cloning, paternity tests,
microarrays
Describe the PCR
process
- increase temperature to 95C to
break hydrogen bonds & split DNA
into single strands - temperature is decreased to 55C so
primers can anneal to template DNA strand - DNA polymerase joins new
nucleotides, forming phosphodister
bonds & makes a new strand
temperature increased to 72C
(optimum for Taq DNA polymerase)
Uses of genetic
fingerprinting
- Forensic science
- medical diagnosis
- plant/animal breeding
- paternity tests
What is gel
electrophoresis
- Separation of DNA fragments using an
electrical voltage - DNA is negatively charged, so it moves
towards the positive electrode - DNA fragments are separated based on
length
→ Shorter fragments move further and
faster through the gel than longer ones
Why does the
DNA move in gel
electrophoresis?
- DNA is negatively charged and
moves towards the positive end
of the gel - the shorter the piece of DNA, the
faster and further it moves
What is genetic
screening?
Testing DNA to identify the
presence of alleles that can
cause/increase the risk of
developing a disease
What is genetic
counselling?
- a type of social work giving people
advice and information following
the screening of disease causing
alleles - provides individuals and families
with information and support after
genetic screening to help make
informed decisions
What is cDNA?
Complementary, single-
stranded DNA strands
created by reverse transcriptase
What are the
advantages of
using the gene
machine?
- Very quick
- accurate
- create intron-free DNA
What are the
advantages of using
reverse
transcription?
Creates intron-free cDNA
What are the
advantages of using
restriction
endonucleases?
Creates sticky ends on DNA to
enable the DNA fragments to
join with complementary base
pairs
Oligonucleotides
- Short DNA molecules
- used in gene machines to create
DNA fragments
