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Bio A2 Level > 19 Gene tech + 16IV > Flashcards

19 Gene tech + 16IV Flashcards

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1
Q

Define term recombinant dna

A

DNA made by joining pieces from 2+ or more different sources

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2
Q

Name the enzymes used in these techniques

  • cutting DNA at specific base sequences
  • making ss DNA from mrna
  • joining pieces of DNA together e.g a gene or plasmid
A
  • restriction endonucleause
  • reverse transcriptase
  • DNA ligase
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3
Q

Describe one example other than desired gene of a section of DNA that can be added to a plasmid

A

Marker gene for floursence
- allows identification of cells that contain recombinant plasmid/transofrmed bacteria
- emits bright light when exposed to UV light
- gene of intrest can be inserted close to marker gene
- GFP/GUS 10
Promotor region
- allows RNA ployermase to bind/trasncription to occur

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4
Q

PCR

A
  • amplify DNA rapidly
  • only small sample of DNA needed

1) denaturation - the double-stranded DNA is heated to 95°C which breaks the hydrogen bonds between the two DNA strands together/seperate DNA strands

2) annealing - the temperature is decreased to 65°C so that primers added + can attach to the ends of ss DNA molecules and CBP

3) elongation - the temperature is increased to 72°C as this is the optimum temperature for Taq polymerase replicates/ form the complementary strands of DNA to produce the new identical double-stranded DNA molecules

  • TAQ polymerase doenst need to be replaced each cycle as heat stable/high opt temp
  • process repeated again
  • semi conservative rep
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5
Q

Method to carry out genetic fingerprinting/gel E

A
  • DNA extracted from a sample (blood, cheek cell)
  • DNA copied/amplified through PCR - VNTR sequence
  • DNA hydrolyzed/fragmented using RE
  • DNA fragments seperated using gel electrophorisis
  • DNa put into well in agarose gel at negative end + electric current passed through
  • buffer solution added
  • probe w floursecnt stain used to show how far DNA fragments travelled through gel
  • Pi groups in DNA neg charged so attracted towards positive electrode
  • Smaller fragments/lighter move further
  • Add flourscently labelled probes + wash of excess and expose to UV light
  • DNA bands matched w sample/compare banding pattern
  • Southern blotting w warm absorbance paper
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6
Q

Explain how a microarray can be used to analyze gene expression

A
  1. extract mRNA from organism
    microarray has ssDNA probes
  2. each probe from a diff gene
  3. reverse transcription of mRNA to produce cDNA
  4. add floursecnt label to cDNA
  5. CDNA added to microarray
  6. CDNA binds/hybridises to probes
  7. Excess cDNA washed off and exposed to UV light
  8. Floursecense shows expressd genes
  9. Intensity of flourscnce shows level of gene expression
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7
Q

explain how a base substitution can lead to production of a non functioning protein

A
  • missense mutation
  • diff trna bases
  • diff AA ss
  • tertiary ss changed
  • change shape of binding site
  • non sense mutation
  • early STOP codon
  • no matching tRNA coded
  • shortened polypeptide
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8
Q

Meisosis I

A

Prophase I:
- Spindle fibre formation
- Nucleur envelope breakdown
- Chromatin condense= chromosomes
Homoglous chromosomes paur up= bivalents form
- Crossing over at chiasmata formation between 2 non sister chrmatids of HC= recombinant chromosomes form (exchange diff combo of alleles)
- linkage groups break/synapsis

Metaphase I:
- Bivallents line up at ewuator
- Spindle fibres attatch to pull centromere
- indepent assortment of homologous pairs
- large number of combos

Anaphase I:
- Chromosomes pulled to opp ends of poles
- centromere divides first
- reductive division

Telophase 1:
- Chromosomes decondense
- Nucleur envelope reforms
- spindle fibres breakdown
- cleavage furrow
- cell ready for cytokinesis

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9
Q

Meisosis II:

A

Prophase II:
- Chromosomes pair up/condense
- Spindle formation fibre
- Nucleur enevlope breakdown

Metaphase II:
- Individual chromosomes line up at equator
- Spindle fibre attatch to centromere

Anaphase II:
- Chromatids seperate
- Centromere divides

Telophase II:
- Nucleur enevlope reforms
- Haploid/chromosome number halved
- 1 set of chromosomes

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10
Q

How gene expression controlled in eukaroyotes

A
  • TF binds to DNA/promotor
  • switches gene on + gene expressed
  • binds to RNA polymerase
  • mRNA made/transcription occurs
  • gene expressed in correct order at correct time in celly cycle
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11
Q

missesne vs nonsene mutation

A
  • M= diff AA ss
  • N= early STOP codon
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12
Q

Explain how an insertion mutation in TYR leads to lack of melanin/albbinism

A
  • Frameshift mutation
  • normal gene is tryosinase
  • tyrosine converted to DOPA
  • melanin made in melanocytes
  • mutant allele is recessive/ Hz recessive
  • tyrosinase not produced
  • change in AA ss
  • change in tertiary ss/ 3d shape/ folding of protein
  • early STOP codon
  • shortened polypeptide
  • loss/lack of function of protein
  • tyrosine not converted to DOPA–> dopaquinoine
  • so dopaquinone cant make melanin via melanocytes
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13
Q

Genetic variation ways

A
  • indepent assortment= random
  • crossing over in Prophase 1/metaphase 1= new combo of alleles
  • gametes unique
  • random mating
  • random fertelisation
  • mutation
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14
Q

explain why meiosis is impt in life cycle of organisms apart from genetic variation of gametes

A
  • reductive division
  • halves choromosomes number
  • so fusion of gametes. (haploid) to diploid
  • prevents chromosome number doubling
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15
Q

Explain how giberellin acts on della proteins to stimulate production on amylase in a germinating seed

A
  • DELLA protein inhibits PIF/TF
  • giberellin binds to receptor
  • DELLA protein break down
  • PIF/TF binds to promotor region
  • Transcription of gene coding for amylase
  • Translation–> amylase produced
  • growth genes switched on/expressed
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16
Q

Explain how diff types of genes can affect phenotype and outline effects of mutatnt alelle that cause HD in person
- gene mutation

A
  • base subst
  • silent mutation of HTT gene/no sig effect on phenotype
  • frameshift due to inversion/deletion of base
  • so sig effect on phenotype
  • CAG repeats- polyglutamine chain
  • each generation, CAG/stutter repeats get longer so onset earlier
  • if over 20 repeats= have condition
  • change in AA sequence/primary ss
  • change in tertiary ss/3D shape of protein
  • loss of function of protein
  • Early STOP codon
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17
Q

Explain how diff types of genes can affect phenotype and outline effects of mutatnt alelle that cause HD in person
- Huntingtons disease

A
  • Mutant allele is dominant- HTT gene, chromosme 4
  • HD allele has more/35 repeats of CAG stutter triplet base repeats= if more than 35 repeats earlier onset
  • Hz will have disease
  • brain degeneration/neurons die
  • tremors/involuntary movements
  • onset in middle age
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18
Q

outline phenotype affects of having abnormal Hb in person w ss anemia

A
  • Hz for mutant allele/Hbs
  • Hb is less soluable in low O2 conc
  • Hb mol stick together
  • RBC sickle shaped
  • RBC poor at transporting O2
  • less O2 transported to cells
  • RBC stuck in capillaries/arteries/veins blocking BF
  • fatigue/and pain
  • Sickle cell crisis
  • protected againt malaria
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19
Q

codominance means

A
  • both alelles expressed in phenotype
  • e.g in blood types
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20
Q

recessive+dominant definition

A

Recessive:
- expressed in phenotype only when dominant absnet
- when homozygous

Dominant:
- expressed if Hz

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21
Q

define gene, locus, allele

A

gene= length of DNA coding for polypeptide/protein

Allele= diff versions of a gene

Locus= position of gene/allele on chromosome

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22
Q

Sickle cell anemia

A
  • HBB gene
  • Hz for mutant allele/Hbs
  • subst mutation
  • GAG to GTG on sense DNA strand
  • GAG to GUG mRNA
  • CAC to CUC on tRNA anticodon
  • glutamic acid (hydrophillic/sol) -> valine (hydrophobic/insol)
    -6/ Beta polypeptide chain
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23
Q

Name protein coded for by lac Y, Z, A ,I and their roles

A

LAC I:
- codes for repressor which binds to operator
- made all the time
- controls gene expression
- (Lac repressor acts as a regulatory mechanism. By binding to the operator in the absence of lactose, it prevents the machinery that copies gene sfrom accessing the lac operon gene//off switch)
- repressor bound to operator + blocks RNA polymerase binding to promotor/gene expression
- in prescene of lactose/allocaatse binds to repressor
- allows transcription of lac operon genes/ repressor conformational change of allosteric site+ RNA polymerase binding to promotor

LAC Z:
- Codes for b-galactosidase enzyme
- digests lactose into glucose + galactose

LAC Y:
- codes for b- galactosidase permease
- allows lactose to enter cell, makes CSM more permeable to lactose

LAC A:
- Codes for b- galactosidase transacetylase gene
- role unknown

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24
Q

Inducible enyzme definition

A
  • not made all the time/constitutive
  • genes switched on/protein made when needed
  • synthesis only occurs when substrate/inducer is present and binds to repressor/transcription factor, e.g. lactose permease
  • triggered by stimulus
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25
Q

explain why male w hemophillia cannot pass conition to male offspring

A
  • males are XY/only 1 X chrosome
  • father passes Y to son
  • father doesnt pass X to son
  • only mother/female passes X to son
  • father passes X/recessive allele to daughter
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26
Q

explain how lele genotype results in dwarf phenotype in sweet peas

A
  • lele codes for non functional enzyme–> 3 beta hydroxylase
  • alanine replaced w theronina at AS
  • inactive giberllin
  • less giberellin bind to receptor
  • less giberellin receptor DELLA complex formed
  • DELLA not broken down
  • DELLA binds to PIF
  • TF/PIF cannot bind to promotor
  • Growth gene not transcribed/expressed
  • STEM doesnt elongate
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27
Q

how a repressor works

A
  • production of repressor protein
  • repressor binds to operator
  • prevents RNA polymerase binding to promotor
  • Structural genes not transcribed
  • repressors are regulatory genes
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28
Q

operon

A
  • length of DNA
  • genes bind together to make specific protein
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29
Q

structure and control of lac operon

A
  • regulartoy gene–> codes for active repressor
  • lac operon has 3 ss genes
  • lac operon uses an inducer
  • Without lactose, repressor protein bound to operator
  • lactose present/ inducer binds + changes shape of allosteric site on repressor protein mol
  • repressor unable to bind to operator/lactose repressor breaks away
  • RNA polymerase binds at promotor
  • genes to be transcribed/expressed/switched on
  • production of beta galactosidase
  • glucose and galactose produced
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30
Q

structural vs regulatory gene

A

SS:
- codes for strucrural proteins/polypeptides e.g lac A, Z,Y
- tRNA, rRNA

Reg:
- codes for proteins that control transcription/gene expression/TF’s
- codes for TF
- binds to promotor
- produced continuously
- synthesis can be prevented by binding of repressor protein to specific site/operator
- TF protein binds to promotor

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31
Q

Repressible enzyme

A
  • End product inhibition
  • X binds to activate repressor to allow binding to operator
  • X stops gene transcription/expression
  • genes coding for protein always on/always made untill subst present
32
Q

why offspring wouldn’t be in a 1:1:1 ratio?

A
  • austosomal linkage
  • no independent assortment
  • recombinance due to crossing over
  • during prophase 1
33
Q

suggest why gene editing/crispr is better gene tech method than vectors for treating dominant conditions compared to recessive ones

A
  • both do insertion of healthy gene
  • healthy gene would be dominant allele allowing normal cell functioning (recessive)
  • faulty gene cannot be removed by vector
  • vectors used for recessive condition/cannot do gene deletion
  • crispr allows for gene deletion for dominant conditions
  • cripsr can work on genes w longer base sequence up to 20 bp, vectors only on up to 10bp
34
Q

adv of crispr over viral vectors

A
  • no risk of immune response when using crispr
  • no risk of infection that may occur w virus if it reverts
  • less side effects, will not switch gene on in regularoy sequence which happens w retrovirus
  • more precise whe targeting DNA because of CBP w cRNA
  • CRISPR gene deletion edits are permanent and can be passed to future generations of cells when the edited cell divides
  • low probability of intergation for viral vector into the cell
35
Q

similarities between cas9 and RE

A
  • part cas9 and RE are endonuscluease
  • both specific to DNA sequences
  • cut both DNA strands
  • present in bacteria and arcahea
  • both hydrolyze PDB
36
Q

diffrences between cas9 and RE

A
  • RE works on palindromic sequence
  • RE form sticky ends + blunt ends, CAS9 only blunt ends
  • RE works on short DNA sequence of 10 bases, cas9 work on up to 20bp
  • CAS9 needs guide RNA to locate specific sequence in DNA strand but RE functions alone
  • cas 9 is more precise
  • cas9 can delete genes/acts on 2 target sites
  • RE only cuts one target site
37
Q

explain why antibodies are not made in babies wo are born w SCID + how to rectify

A
  • ADA not made due to mutation in T lymph
  • chromsome 20
  • deoxyadenosine accumulates in T lymph cells to toxic levels = die
  • deoxyinosine not made/non toxic
  • no clonal exoansion
  • no cytokines form Th/less Th
  • no cloning of B plasma
  • B plasma cannot make antibodies
  • immunocopromised/immodieficent
  • vector is retrovirus
  • Ex vivo
38
Q

Uses of gene editing

A
  • editing mutations that cause cystic fibrosis located in a gene called CFTR
  • make crops more nutritious, able to resist disease or grow in difficult conditions
  • make animals more disease resistant
  • designer babies – choosing/hair, colour, or gender
  • genetic modification of embryos would be passed onto descendants
  • designer pets
  • more virulent strains of disease for biological weapons
  • superhuman race, no disease in the wealthy
39
Q

Outline the advantages of screening for genetic conditions

A
  • reduces stress
  • identifies carriers/increased risk of person having disease e.g BRACA 1 gene BC so can do IVF
  • genetic counselling
  • lifestyle changes
  • make a will
  • allows ppl to prepare for late onset genetic condition e.g Dementia
  • choose to have children or not- if fetus will develop genetic condition give tretament when born
  • prepare for birth of child who will need tratment long term/lifelong
  • provides early diagnosis
  • preventative treatment e.g masectomy
  • theraphutic abortion
40
Q

Discuss the social and ethical implications of using gene tech -adv

A

ETHICAL SOCIAL FOR GENE TECH:
advantage:
- cheaper
- more effective medicine
- can prolong lives of people with genetic disorders
- only wealthy can use

41
Q

ADV of screening for genetic conditions:

A
  • know about increased risk of genetic conditions, e.g. breast cancer
  • allows people to prepare for late onset genetic conditions e.g HD
  • identify whether fetus will develop genetic condition so can give early treatment when born
  • allows parents to prepare for birth of child =treatment for long time or throughout life
  • identifies carriers of genetic condition
  • helps to provide early diagnosis
  • allows couples who are both carriers of genetic condition to make decisions about starting family e.g IVF or terminaation
42
Q

Disadv of gene theraphy

A
  • cause antibiotics to become less useful as more bacteria become resistant
  • cause, allergic reactions or disease
  • effects of treatment may be short-lived
  • patient may have to undergo multiple treatments
  • maybe difficult to get the allele into specific body cell
  • body could identify vectors as foreign bodies and immune response against them
  • could be inserted in the wrong place and DNA causing cancer
  • expensive ;
  • cultural / religious, objections ;
  • stressful ;
43
Q

Discuss the ethical implications of IVF

A
  • not natural, technological process e.g multiple births
  • possible birth defects
  • only wealthy can access IVF
  • some embryos discarded
  • unknown effects of freezing embryos for storage
  • issues regarding selection of gender
    -issues regarding regarding egg donations/surrogate, mothers
44
Q

Ethical/social ADVANTAGES for embryo pre-selection and therapeutic abortion (disadv same as IVF)

A
  • better quality of life
  • less anxiety
  • less expensive to keep healthy baby than diseased
  • noGene therapy/medicines for certain medical conditions, so better to choose embryo that doesn’t have those diseased alleles
45
Q

Discuss the potential advantages of growing genetically modified crops

A
  • increase food production/crop yield
  • improve food, quality/taste/shelf life
  • add nutrients to crop e.g. vitamin A in golden rice
  • crops, more tolerant to climate change
  • crops do not need as much fertiliser
  • pesticide, pest/insect/fungal resistant
  • cost-effective to farmer
  • less effect on food chains
  • herbicide resistance reduces competition from weeds as weeds killed
  • GM crops increase a country’s wealth;
  • GM crops relieve, hunger/ starvation ;
46
Q

Outline the disadvantages of using plants that have been genetically modified

A
  • GM seeds could be difficult for farmers in developing countries to obtain
  • high cost of buying GM seeds
  • might reduce efforts to relieve poverty
  • possible, allergic reactions in humans/toxicity of more herbicide left after use
  • loss of genetic diversity/biodiversity
  • Harm to other species effect on rest of food chain
  • GM crop may be invasive
47
Q

Role of transcription factors

A
  • binds to DNA/promoter
  • RNA polymerase binds to promoter
  • transcription begins/genes, express/genes switched on
  • activates genes, incorrect order/time/cells
  • regulate cell cycle/role in cell cycle, checkpoints/apoptosis
48
Q

Explain what is meant by bioinformatics and the role of it

A

– Analysis of biological data, using computer software
- LARGE amount of data/databases of gene/DNA/amino acid sequences
- fast accurate efficient data/access quickly
- Data can be shared
- can predict amino acid, sequences/protein structure
- BLAST (search tool for DNA nucloetides sequences) , uni prot (AA sequences), ENSEMBLE (nucletode sequences) = analytic tool
- make comparisons
- share data / access data quickly ;
- compare (amino acid / nucleotide / base / DNA) sequences ;
- predict / visualise / model, the ss of proteins ;
- identify X to use, find new X
- looj at species biodiveristy/new species
- vaccines for malaria
- perosnalised medicine
- idenitify new disease
- workout common ancestor

49
Q

Describe how haemophilia occurs and vector of choice in gene tech

A
  • chromosome X, 23
  • Factor VIII glycoprotein is faulty
  • extract mRNA usuing RE to cut DNA sequence at specific restron sites = complinetry stick eynds
  • cut plasmid to form complimnetry sticky ends
  • use DNA ligase to form PDB between SPB and plamsid
  • insert DNA in host cell = hamster kidney ovary cell/kidney
  • synthesize from RT, cDNA
  • electric shock = make the membrane more fluid so plamid can enter/ Ca2+ ions make it non polar
  • prothrombin cannot be converted to thrombin
  • thrombin cannot convert fibrinogen to fibrin
  • no blood clot and uncontrollable bleeding
  • recessive inherited disease
  • because contains RER and Golgi needed for translation and modification to make glycoprotein
  • contains and exons
  • bacteria have no double membrane, bound organelle
50
Q

Describe cystic fibrosis and vector of choice

A
  • CFTR protein acts as a Cl- channel in CSM of epithelial cells e.g respiroty tract, reproductive tract
  • blocks digestive tract, pancreatic duct SO malabsorption of nutrients, insulin not relased= diabetic –> take digestive enzymes + inject insulin
  • sperm duct blocked if want kids/infertile + oviduct blocked = do IVF
  • faulty, CFTR gene protein produced
  • Cl- ions cannot move out of cell by AT = lowers WP, as Cl- buildup
  • so less water passes out of EP cell down WPG ,by osmosis
  • mucus secreted w less water = thick and sticky
  • use liposomes, which are modified to become positively charged
  • surrounds the plasmid -
  • insert CFTR into plasmid using RE and DNA ligase
  • liposome w gene enters cell by endocytosis using in vivo method,trancription/translation + makes CFTR protein channel
  • placed in nebuliser/inhale and enters respiratory tract
51
Q

properties of plasmids that allow them to be used in gene cloning

A

1)easy to extract from bacteria
2)can be cut using RE
3)gene/DNA can be inserted + taken up by bacteria
2) can be transferred between different bacterial species
3) can be produced artificially
4)can carry marker genes
5)acts as vector
6)may carry promotor
5) replicate independently in bacteria
6) - small and ciruclar piece of DNA
7) high copy number

52
Q

disadvantages of using antibiotic-resistant genes as marker genes

A

1) risk of antibiotic resistance genes spreading to other bacteria, producing pathogenic (disease-causing) strains that can’t be killed by antibiotics
2) if the resistance spread to other bacteria this could make antibiotics less effective

53
Q

restriction endonucleases

A

an enzyme that binds to a specific target area on DNA and cuts it at the site

54
Q

plasmid + vector

A

small, circular pieces of double-stranded DNA

used to deliver genes into a plasmid

55
Q

advantage of using fluorescent genes as markers instead of AntiR gene markers

A

1) they are easier to identify (all that is required is the ultraviolet light)

2) more economical (do not need to grow the bacteria on plates of agar infused with antibiotics)

3) no risk of antibiotic resistance being passed onto other bacteria

4) there are antibiotics that are no longer effective and therefore would not stop any bacteria from growing

56
Q

role of promoters

A
  • region of DNA that determines which gene will be expressed as it’s the region of DNA to which RNA polymerase binds as it starts transcription
  • 1) ensures that RNA polymerase recognises the template strand
    2) transcription start-point
    3) the promoter is used to regulate gene expression because only if it is present will transcription and therefore the expression of the gene occur
57
Q

(DNA) ligase

A

formation of PDB in the DNA sugar-phosphate backbone

58
Q

producing recombinant insulin + placed in plasmid vector

A
  • obtain mRNA from B cells of iselts of langerhans of pancreas
  • reverse trans make cDNA
  • DNA polym used to make DNA double ss, sticky ends created
  • obtain plasmid from bacteria
  • cut w RE at specific Rs
  • Complimentry stick eynds
  • cDNA/insulin gene mixed w plasmid usuing DNA ligase forms PDB between SPB
59
Q

cystic fibrosis

A
  • CF is an autosomal recessive genetic disorder caused by a deletion mutation of 3 bases (AAA) of the gene that codes for a transporter protein- CFTR on chormome number 7
    ‣ it is a progressive disease in which abnormally thick mucus is produced in the lungs/pancreatic duct, ducts in the reproductive system)
    ‣ the faulty CFTR protein no longer transports Cl- ions across the CSM so water does not move by osmosis across the membrane
    ‣ there is no cure for cystic fibrosis, although there are many different treatments that help alleviate symptoms
60
Q

genetically modified oil seed rape

A
  • a source of vegetable oil which is used as a biodiesel fuel and lubricant
  • natural rape seed oil has toxic erucic acid and glucosinolates
  • when growing oil seed rape, weeds competing w it, so yield decreases so sparyaed w herbicide
  • so weeds and OSR not grown
  • take enzyme making these 3 AA from Agrobacterium + the gene transferred into OSR plants so can continue to grow not weeds
  • modified oil seed rape is resistant to the herbicide glyphosphate inhibits 3 AA:tysroine, tryptophan and phenoalinine and contains lower concentrations of erucic acid glucosinolates

\

61
Q

outline how to do GE to give trait of insect resistance

A
  • gene(s) from, another species/ (soil) bacterium/ B.(acillusJ thuringiensis;
  • restriction, enzyme I endonuclease ;
  • plasmidI vector/ virus/ liposome
  • (DNA) ligase ;
  • (forms) recombinant, DNA/ plasmid /vector;
  • new gene I rDNA / plasmid, enters, maize I MON810, embryos I cells I genome I DNA ;
  • gene, expressed /transcribed (and translated), to make, protein /toxin;
  • ref to marker genes/ insert promoter ;
62
Q

TF vs Promotor chem diffrences

A

Protein vs DNA
AA vs nucleotide
Peptide bond vs PDB
CHONS vs CHONP

63
Q

describe how crossing over produces GV in a pop

A
  • (crossing over is) between non-sister chromatids ;
    -(non-sister chromatids have) different combinations of alleles
    -exchange alleles ;
    -(chromatids have) new combinations of alleles ;
    -linkage groups broken ;
  • gametes have unique combination of alleles ;
    -random fusion of gametes (during fertilisation) ;
64
Q

explain F1 generation

A
  • (first) gen of offspring (from parental cross) ;
    -true bred / pure bred / pure breeding ;
  • if parents homozygous then F1 generation will be heterozygous
65
Q

outline 2 sources other than messanger RNA which genes can be obtained from

A
  • genes extracted from donor DNA
  • genes synthesised from nucleotide
66
Q

suggest 2 reaosn why phenotypic rations in F2 gens dont always match expected ratio

A

1 epistasis ;
2 linkage ;
3 lethal allele ;
4 chance deviations ;
5 environmental effects ;
6 mutations ;
7 small sample size ;

67
Q

explain why cattle SB is harder than crop SB

A
  • longer time to, grow / mature ;
  • fewer offspring (per cross / AW) ;
  • feature can only be measured in, about 50% of offspring / females ;
    -milk yield must be measured over period of time ;
  • to ethical issues ;
  • difficulty in identifying suitable males for use in crosses ;
  • cattle require more, care / support/ more expensive ;
    -more dangerous to carry out breeding of large cattle
68
Q

state 2 examples of crop features that may be imrpoved by SB to increase crop yield

A
  • mass / quantity / size ;
  • disease resistance ;
  • resistance to, insects / pests ;
  • increased rate of growth ;
    -drought resistance ;
    -resistance to herbicides ;
    -; e.g. resistance to, flooding / wind/ethanol
69
Q

how to use genetic enginneing/GM to produce specific RE

A
  • obtain RE/gene
  • gene extracted from the, DNA / genome of bacteria
  • PCR to make more copies of, gene/DNA
  • cut a plasmid, with RE / to give sticky ends ;
  • combine / join, gene with plasmid using ligase ;
  • add plasmid to, E. coli / bacteria
  • use marker genes to, select / identify, bacteria / E. coli, with recombinant plasmids ;
  • use fermenter ;
  • heat shock add calcium ions
  • complementary sticky ends anneal / make PDB
70
Q

outline main features of lac operon

A
  • promoter ;
  • operator ;
  • 3 structural genes
    lacZ = b galactosidase gene
  • lacA =b galactoside, permease gene
  • lacY = transacetylase gene
71
Q

outline procedure of gene theraphy for ADA

A
  • given a drug to increase number of stem cells
  • virus / vector, containing, normal / healthy, allele ;
  • ADA mRNA is extracted from cabbage looper moth catepillar
  • use reverse T to make cDNA of healthy ADA gene
  • remove, bone marrow / stem cells ;
  • mix stem cells with, viral / vector (to allow transfer of normal allele) ;
  • radiotherapy / drug, to make space in bone marrow / to kill stem cells
  • cells, infused / injected, into blood ;
  • (lymphocytes) produce functioning ADA ;
  • adeno-associated virus
  • tissue from bone marrow, purified / sorted, to obtain stem cells
72
Q

adv. of gene theraphy

A
  • cure / long term treatment / no longer chronically ill / better quality of life ;
  • no need for regular, injections / treatments
  • only a single treatment ;
  • no donor needed ;
73
Q

Types of vector

A

Naked DNA
- fewer side effects
- cheaper
- injected directly in target cell
- low efficeny of cellular uptake = need to inject MORE of gene
- rapidly broken down
- no risk of immune reponse= no capsid
- low risk of cancer/mutation

Liposomes:
- Low ability to add DNA/gene into target cell
- low transductional efficeny
- In vivo doenst neccesarily have to do endocystosis to target cell
- low risk of immune response/no capsid/antigen s
- low risk of affecting reg sequence
- high packaging capapcity

Viruses:
- Retro/Lenti/AAv
- small packing capaocty so small amounts of DNA
- low probability of intergartion into host geome
- causes mutations in host DNA
- Retro= RNA virus, use Ex vivo, RT, specifc cells targted, used in dividing cells, cancer/HIV if reverts to be infectious
- LentiV= modified Retrovirus (ssRNA) so doesnt intergarte within chromome and switch gene on in reg sequence, self inactivated, ex vivo, HIV if reverts
- AAV= DNA virus, ssDNA so delayed expression when making double ss, non dividing cells e.g retinal cells and neurones, long term, use in Vivo, no risk of cancer/regularoyt seuqnec effect as stays in cytoplasm, small packaing capacity.

74
Q

explain how genetic diseases may be treated using gene theraphy

A
  • normal genes/allele, insert into vector
  • liposomes as vectors in inhaler
  • liposomes fuse with host cell
  • short term effect
  • repeat treatment needed
  • side effects
  • symptomatic treatment
75
Q

explain how bacteria can be GMO and identified usuing Anyibiotic resistant gene

A

-R plasmid mixed with bacteria
- bacteria, transformed/plasmid
- heat, shock/calcium ions for permebeaility of membrane
- grown on agar/medium containing antibiotic/ampicillin
- bacteria with plasmid survive
- absorbent paper onto agar With second antibiotic
- resistant, gene inactivated
- colonies from first plate that do not grow on second plate extracted

Bio A2 Level (8 decks)

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