19:mutations, transformations, plasmids Flashcards
What are the types of mutation?
silent: genotype change but no phenotype change
missense: change in phenotype that changes the amino acid
frameshift: insertions/deletions that change reading team
How can enzyme mutation impact amino acid synthesis
if an amino acid changes in the active site of an enzyme, substrate cannot properly bind. Phenotype is not noticeable in large group but is noticeable in a small group
what is spontaneous mutations
mutation that occur via normal cell rep, requires 2 rounds of replication to become legit bc need base pairing of wrong NT
How do enol forms cause mutation?
enroll forms have alternate base pairing abilities, when thymine at low concentration, may bp with guanine and from 3 HB instead of 2
How does H2O cause mutation?
DNA bases may react with water. cytosine can be deaminated and react with uracil
deprivation: loss of base from backbone
How does O2 cause mutation?
ROS may form and oxidize DNA bases to change their properties
DNA pol matches w wrong base
only anaerobic organisms
What are mobile genetic elements/jumping genes?
Transposable elements encode for transposes which can bind to genome sequence with inverted repeats, excise the DNA, then insert itself into new DNA at specific insertion sequence
how can jumping genes be used in lab?
deliver sequence specific transposed to bacteria pool, mutate any gene within organisms and disrupt that gene, can pass gene through animal, recover bacteria and determine where transposon was inserted
what are the types of environmental mutagen?
UV light: causes crosslinks between neighboring rings
ROS: phagocytes in body produce ROS to kill pathogen->oxidize DNA
ionizing radiation: ds breaks in DNA
What happened with deinococcus radiodurans?
canned meat blasted w radiation, gained resistance to UV light
What us homologous recombination?
ds break occurs in DNA, nuclease looks for homologs sequences, chews back strands to make single strands, recA binds ssDNA and searches for other complimentary DNA to bp. Polymerase copies and extends DNA, DNA sealed with ligase. When strands exchanged, this is called homologs recombination
What is horizontal gene transfer
genes transferred between unrelated bacteria too cause a phenotypic change. traducing particle is inserted into new host with correct homology to cause homologous recombination
What is transformation?
ability of cells to take up extracellular DNA and and pull it into the cytoplasm, recA binds ssDNA and finds homologous region
What is the Griffiths experiment?
capsular polysaccharide dead cell and non capsular polysaccharide alive cells combined to make capsular polysaccharide alive cells
What are plasmids?
nonchromosomal genetic mutations, heritable with origin of replication
can be single or multicopy
do not contain essential genes, can have antibiotic resistance, virulence, toxins, immunity
