transformation Flashcards
what is this the definition for? a virus infects a bacterium and some bacterial DNA is entrapped in the viral capside; this virus infects another bacterium and transfers the DNA of the previous bacterium
transduction
what is transformation?
the bacteria gains a trait by taking in DNA from its environment
what is conjugation?
Transfer of DNA from one bacterium (F+) to other (F-) through sex pilus and with the help of F factor plasmid is
are bacteria diploid?
no
what is the impact of bacteria being haploid? are they easy to grow?
yes easy to grow and test traits, also show no dominance or recessivity
how is there bacterial variation?
from errors e.g DNAP
what is an auxotroph?
a mutant organism, especially a microorganism, that has a nutritional requirement not shared by the parent organism. (it cannot synthesize compound needed for growth)
what is a prototroph?
an organism able to grow and survive on minimum conditions (it provides its own compounds needed for growth)
when did Griffith perform his experiments?
1928
what were griffiths observations?
virulen strain=smooth non virulent=rough then in mice experiments mix of heat killed smooth and non virulent still caused mice to die –> discovered transformation
what did Frederick Griffith discover in 1928
transformation
what did Avery,Macleod and McCarty demonstrate?
they showed the ‘transforming principle’ was DNA
how did Avery,Macleod and McCArty demonstrate DNA was the transforming principle?
added RNAse,protease and DNAase to the same mix(heat killed virulent and non virulent strain) and only the one without DNA stayed non virulent
in transformation what type of DNA attached onto the cell and what type is taken up?
dsDNA binds to cell,endonucleases mean only ssDNA is actually moved into the cell and this ssDNA is inserted into the bacterial chromosome by recombination
what 3 problems can occur in transformation?
1)dsDNA may not attach to cell 2)ssDNA may not be taken up into cell 3)ssDNA may not be incorporated into the chromosome by recombination
which process allows ssDNA to get into the bacterial chromosome in transformation?
recombination
in transformation is the cell the info is being picked up from dead?
yes
why undergo transformation? (3)
nutrition,repair and variety (adaptation)
if two donor genes are located closely on the chromosome what is there a greater chance of?
they will be carried on the same piece of transforming dna and therefore greater chance of double transformation
what can transformation be used for?
to assess linkage (test for a departure from the product rule)
in transformation does the donor DNA replace a large percent of the recipients chromosome?
no, only a small percent (cotransformation is because thE genes are in close proximity to one another)
What are PLQ?
pores that allow DNA to reach import system
what is ComEA protein responsible for?
reception of dsDNA on cell surface which is then nucked by endonucleases to become ssDNA
what do endonucleases in a competent bacterial cell do?
nick the dsDNA to make it ssDNA
