gene expression Flashcards
what are the 4 types of stem cell🧪
totipotent, pluripotent, multipotent, unipotent
to what extent can these stem cells differentiate?
totipotent, pluripotent, multipotent and unipotent
🦜🛤️🌱🐉🧪🌴💓
totipotent- any cell
pluripotent- most cells
multipotent- some cells
unipotent- one cell
Induced Pluripotent Stem Cells are a Future Stem Cell Therapy.
what can iPSCs be used for?💞
they can regrow damaged tissues
what is DNA polymerase?🫧💕
an enzyme which manufactures DNA by joining nucleotides (using a complementary strand as a blueprint)
what’s a gene machine?🎀
a computer controlled device that can be programmed to produce short sequences of DNA
what is DNA ligase? 🧬
an enzyme which can join the phosphate-sugar framework of two sections of DNA eg joining sticky ends
what’s a primer?💐
a short sequence of nucleotides with a set of bases complementary to those at one end of each of the two DNA fragments
what is restriction endonucleases?🧚🏼
an enzyme that can recognise specific base sequences in DNA and cut the DNA at that site (the restriction site)
what are the 3 ways to obtain a copy of a gene sequence?💓
-using reverse transcriptase
-using restriction endonucleases
-using a gene machine
what is recombinant DNA?🪷
where DNA from different organisms or sources is combined together
how do you make DNA from mRNA?
which 2 enzymes are used?
what has to be made first?
🛤️🛖🌿🦎🌱💓
mRNA ———> cDNA ———> DNA
reverse DNA
transcriptase polymerase
what’s a palindrome?☀️
when the sequence reads the same backwards as forwards
what are sticky ends?
what can they do?🌊
small tails of unpaired bases
they can hydrogen bond to complementary sequences
what do these enzymes catalyse?💞
-restriction endonuclease
-DNA polymerase
-reverse transcriptase
-DNA ligase
-recognition and cutting of DNA at specific base sequences
-formation of a new DNA strand during DNA replication
-production of a cDNA fragment from an mRNA strand
-binding of DNA fragments
what is gel electrophoresis?🧪
a process used to seperate the DNA fragments and proteins according to their size using an electric current
what is genetic fingerprinting?💞🧬
a technique that can detect differences in people DNA using short repeating bases (VNTRs)
what is in-vivo cloning?💞💝💕
example?
how long is the process?
takes place inside a living organism.
eg. DNA fragments can be transferred to a host cells where they’re amplified
long
what are proto-oncogenes?
what are oncogenes?
🪼🦎💓
proto-group of genes involved in promoting cell division
oncogene-mutated proto-oncogenes, they’re permanently switched on which overstimulates cell division
what’s in-vitro cloning?🐠🐋🐟
example?
how long?
takes place outside of a living organism, in a controlled environment eg test tube
eg DNA is amplified using a PCR in a thermonuclear
makes millions of copies of DNA in hours
what does siRNA do?
how does it do this?
🧬🧪💓
it interferes with translation
it binds to mRNA which prevents it from being translated in the cytoplasm
therefore the gene it codes for isn’t expressed
what are 4 types of mutation?💓
additional, deletion, substitution, duplication
what are dna probes?🏄🏼♀️
short single stranded dna labelled fluorescently or radioactively
they’re complementary to the allele being screened for
whats hybridisation?😊
what’s detection?😴
when probes bind to the sequence
when probes are tagged so we can detect and count them
pros and cons of genetic fingerprinting?🏝️
+ high specificity
- needs prior knowledge of sequence, can get false pos or negs,
uses of genetic fingerprinting?🌊
genetic screening, personalised medicine (targets ur genes), genetic counselling (risk of conditions), cancer management
what type of bases does gel electrophoresis need in order to work☀️
non-coding bases (VNTRs)
describe the process of gel electrophoresis💗
extract DNA
cut fragments with restriction endonucleases
DNA is placed on agar and voltage is applied
small fragments at the top and larger stay at bottom due to gel resistance
DNA samples labelled with probes bind with the comp VNTRs
xray film placed over the membrane shows position of the fragments
shows the bars which is diff for everyone
making DNA fragments
how does genetic engineering and restriction enzymes work?🩷
genetic engineering- taking a gene from one species and putting it in another
restriction enzymes- cut double stranded DNA at specific sites-produces sticky ends
making DNA fragments
how does reverse transcriptase work?🌆
extract mRNA (not DNA as there’s more copies)
then mix if with free nucleotides and use reverse transcriptase to form cDNA- can then form DNA or something
making DNA fragments
how does a gene machine work?🫶
fix nucleotides onto a support
protecting groups prevent branching of the chain
oligonucleotides are synthesised, protecting groups removed and larger fragment is made
making DNA fragments
how to make a transgenic organism?☀️☀️
deliver fragment into organism using a vector eg plasmid
plasmid cut using the same restriction enzymes- makes comp sticky ends
fragment inserted to plasmid using DNA ligase
modified plasmid is recombinant DNA
what are sticky and blunt ends?🪸
sticky-still had single stranded areas at the end
blunt-straight cut
