chemical mutagens
Terms
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- early replication
- virus genetic material
- chemical mutagens
- combine with nitrogen base which alters them and causes them to mispair Ex: Nitrous acid --- combines with A and causes it to pair with cytosine
- replication in genetic engineering
- lytic cycle - productive increase in number of viruses
- Impersonating the nitrogen base will
- incorporate into the DNA and lead to faulty pairing Ex: 5-bromacil looks like thymine (5BU) pair with guanine instead of Adenine
- later replication
- viral structurtal protiens
- High frequency recombient (HFR)
- F plasmid --- chromosome cell becomes HFR HFR mate with F- cell
- shapes of genetic engineering
- icosahedral, helical, and complex
- pharmacuticals
- human growth hormone gene product -- treatment
- Lysogeny
- non productive no new virus particles
- Ionizing-radiations
- X-rays, gamma rays - DNA damage
- adsorption for lysogeny
- very specific to receptors on host cell and structures on the virus
- When occassionally a virus replicates
- it will pick up a piece of host DNA instead of virus DNA
- penetration
- virus or nucleic acid will enter the host cell
- Forward mutaion
- mutant can't make histadine requires histadine as a nutrient
- penetration of bacteria by injection
- 1. membrane fusion - enveloped viruses fuse with plasma membrane of the host (additional step - uncoating - viral nucleic acid released from capsid. 2. phagocytosis - enzyme brings virus in
- Radiations
- UV structural changes in the DNA
- penetration replication
- make more copies of itself often involves destruction of host DNA/ virus genetic materiak can control the metabolism of the cell
- gene therapy replacement of a faulty gene
- engineer virus -- remove pathogenic gene replace with foreign gene = infected host, microinjection, liposomes, gene guns -- DNA + gold particle -- shot with a gene gun
- burst size
- number of viruses that come out of the host cell 50-200 new viruses
- Transfer DNA donor
- recipient to move DNA into cell
- Lysozome - destruction of PTG
- envelope added to the virus leaves the host cell through the modified areas of the plasma membrane
- Conjogation
- donor cell F + = F plasmid genes sex pilus, genes transfer recipient F- = no F plasmid
- capsid protein coat functions
- protect the viral nucleic acid, shape - symettry, attachment to host cell, antigen, some bilayer lipid envelope surround capsid, envelope may contain glycoprotein -- spikes
- Applications for genetic engineering
- pharmacuticals, agriculture, gene therapy, and gene mapping
- burst time
- adsorption - relaese 20 mins for bacterial viruses
- Back mutation
- reverse of original mutation does not require histadine as a nutrient can make its own (less likely)
- adsorption attachment of viruses to host cell
- very specific receptors on host cell and specific structures on the virus
- agriculture
- frost ban -- gene from bacteria inserted into potatoes & strawberries makes them resistant to freezing
- penetration for lysogeny
- nucleic acid enters host cell, integrate onto host chromosomw --- repressor protein
- F+ plasmid transfers to F- cell genes for:
- making sex pilus, transfer gene, antibiotic resistant gene R = plasmids
- assembly and release for bacterial penetration
- assembly mature virus particle, release mature virus particles from host cell, usually lysis of host cell
- Basis for genetic engineering
- *Double stranded DNA - genetic materia in all living organisms * DNA replication same * genetic code is the same * segment of DNA, any source replicated any cell * DNA out, alter in lab - living cell replicates
- helical
- nucleic acid wound into helix, capsomeres atach to helix
- 2 events for gene exchange in bacteria
- donor DNA enters recipient cell and the donor DNA enters chromosome
- icosahedral
- cubic - 20 sided each side triangle (looks like a crystal)
-
Transformation Griffin - 1928
S = smooth strain
R = rough strain - released DNA fragments donor dead smooth, live R recipient must be in a state of competence log phase, to take up DNA fragments, complimentary base pairing can now make capsule by exposing to piece of DNA from the donor
- During virus replication
- virus released from cell --- will infect new cell; inject DNA into new cell host DNA --- integrate onto recipient chromosome
- Ames Test
- screening method to determine if a chemical is a carcinogen - cancer (most mutagens are carcinogens)
- Transduction DNA from donor recipient via bacterial virus
- virus will attach to host cell, host DNA virus enters host cell, host cell DNA degrades, virus replicates host cell lyses --- viruses
- Genetic Engineering
- intentional mixing of genes other species by artifical means
- 4 steps to transfer DNA
- 1. isolate plasmid and gene of interest 2. cut plasmid and gene of interest 3. mix cut plasmid and gene --- fusion 4. engineered plasmid --- replicate makes more copies of foreign gene gene product protein
- nucleic acid structure for genetic engineering
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single stranded DNA
single stranded RNA
double stranded DNA
double stranded RNA