Topic Eight - DNA Technology Flashcards
what effect does deletion have on DNA?
frame shift to left
what effect does addition have on DNA?
frame shift to right
what effect does duplication have on DNA?
frame shift to right
what effect does inversion have on DNA?
makes a different/ non-functional protein
what effect does substitution have on DNA?
- makes a stop codeon = protein cut short
- codes for a different a.a = different/non-functional protein
- no effect (degenerate code)
what does translocation do to the DNA?
cuts one chromosome short and adds the gene onto another chromosome
what effect does translocation have on DNA?
changes gene expression
what cell types can totipotent stem cells differentiate into?
any cell type
what cell types can pluripotent stem cells differentiate into?
many cell types
what cell types can multipotent stem cells differentiate into?
limited cell types
what cell types can unipotent stem cells differentiate into?
1 cell type
where are pluripotent cells found, and what is the ethical issue?
embryo - destroyed
foetus - aborted/miscarried
where are multipotent cells found, and what is the ethical issue?
adult bone marrow - painful + risky
umbilical cord - naturally detaches
what are iPS cells?
unipotent cells that are genetically altered to have characteristics of embryonic cells (pluripotent)
what does an active binding site on a transcription factor do?
stimulates transcription
what does an inactive binding site on a transcription factor do?
inhibits transcription
how does oestrogen initate transcription?
- binds to receptor on transcription factor
- TF’s tertiary structure changes = complementary to DNA
- Tf moves to nucleus
- binds to a specific DNA sequence
- imitates transcription
how is oestrogen linked to breast cancer?
- after menopause more oestrogen produced
- more transcription
- tumour
- increase in oestrogen conc.
- increases tumour development
definition: epigenetics
heritable changes in gene function without changes to the base sequence of DNA
what does the epigenome do?
determines the shape of the DNA-histone complex
what is the epigenome?
the layer of tags that covers DNA + histones
what can effect the epigenome?
stress, diet, exercise
what happens when the DNA is tightly packed?
Tf + RNA polymerase can’t reach genes
= transcription is inhibited = gene is inactive
what happens when the DNA is lossley packed?
Tf + RNA polymerase can reach genes
= transcription is stimulated = gene is active
where are tags found on the DNA?
methyl groups - bind to DNA
acetyl groups - bind to histones
what is acetylation?
addition of an acetyl molecule
that is donated from Acetyl CoA
what is methylation?
addition of CH3
its added to the C base of DNA
what causes translation to be inhibited?
increased methylation
decreased acetlyation
what causes translation to be stimulated?
decreased methylation
increased acetylation
how does gestational diabetes occur?
- fetus is exposed to high conc. of glucose
- = epigenetic changes in daughter’s DNA
- increases chance she gets it
what are the two types of RNAi, and their diffrences?
miRNA (single stranded)
SiRNA (double stranded)
how does RNAi stop translation?
miRNA / 1 strand of SiRNA, binds w a protein complex = RNA induced silencing complex (RISC)
RISC binds with mRNA, stoping translation by:
breaking mRNA OR prevents ribosomes from attaching to mRNA
what are the diffrences between benign and malignant tumours?
benign:
- localised effect
- less life threatening
- removed by surgery
- rarely reoccur
malignant:
- systemic effect
- more life threatening
- removed by surgery and treatment
- more likely to reoccur
what do tumour suppressor genes do?
- slow/prevent cell division
- repair DNA mistakes
- apoptosis
what happens when a tumour suppressor gene is inactive?
HUGE increase in cell division = tumour
how do tumour suppressor genes become inactive?
- gene mutation
- increased methylation
what do proto-oncogenes do?
increase cell division
what are oncogenes?
mutated proto-oncogenes
what do oncogenes do?
HUGE increase in cell division = tumour
what is gel electrophoresis used for?
to seperate
DNA - by mass
RNA - by mass
proteins - by mass or charge
what are the three ways a protein fragment is produced?
restriction endonuclease
reverse transcriptase
gene machine
what are the three ways a DNA fragment is produced?
restriction endonuclease
reverse transcriptase
gene machine
how do restriction endonuclease create DNA fragments?
they cut DNA @ recognition sites
= blunt ends or sticky ends
how does reverse transcriptase create DNA fragements?
- adds nucleotides to mRNA molecule = new strand called cDNA
- enzyme destroys mRNA strands
- 2nd strand is built by DNA polymerase = complete DNA fragment
how does the gene machine create DNA fragements?
- sequence is generated from the database
- safety check
- computer designs oligonucleotides
- oligonucleotides join to make a gene
what happens in in vivo cloning?
- DNA fragment is prepared
- insert fragment into the vector, using DNA ligase
- place into host cell (use Ca2+ & heat shock)
- identify bacteria with recombinant DNA (enzyme, fluorescence, antibiotic resistance)
- multiply bacteria
what is replica plating?
- taking sample of bacteria into a new plate with the antibiotic, bacteria is at the same place
- bacteria that dies = has the recombinant DNA
what is the process in in vitro cloning?
PCR
1) heated to 95°C -> breaks all the H bonds
2) cooled + DNA primers attach
3) heated, taq polymerase + nucleotides attach to each strand
what are the two ways of labeling DNA probes?
radioactive and fluorescent
how do you screen for genetic disorders?
- multiply the DNA probe (PCR)
- heat the DNA sample
- Add probes + cool mixture
- wash DNA sample
- check for attachment
what are VNTRs?
repetitive, non-coding DNA sequences that are directly next to each other
how is genetic fingerprinting done?
- collect DNA sample
- use PCR to multiply DNA
- restriction enzymes are used to produce VNTR DNA fragments
- use gel electrophoresis to separate VNTRs
- add alkali to separate VNTRs into single strands
- add complementary DNA probes to identify VNTRs
- Compare VNTR patterns
