Module 2 Flashcards
What is a monoploid?
One copy of the genome
What is diploid?
Twi copies of the genome
What is haploid?
Number of chromosomes in sperm and egg
What is a prototrophs?
Bacteria that produce everything it needs to live
What is auxotroph?
Mutant bacteria that requires additional needs
How do bacteria swap DNA?
Transformation, conjugations, transduction and horizontal tranfer
What is transformation?
one bacterium takes up DNA expelled from a dead bacterium
What is conjugation?
direct transfer of a DNA strand from one bacterium to anotherWh
What is transduction?
virus transfers bacterial genes from one bacterium to another
What is horizontal transfer?
DNA is transferred between two different bacteria
How did they figure out transformation of DNA?
Deadly bacteria added to mice (kills mice, heat-killed added (alive), good bacteria added (alive) and then heatkilled bad and alive good (mouse died)
How did they determine that DNA was the cause of the swap?
Heatkilled and bacteria and DNAase and RNAase etc added together. To see what colonies grow.
How did they discover conjugation?
Two rich cultures, placed onto minimal medium, no growth. When incubated together, growth. DNA was swapped.
How does conjugation occur?
Homologous recombination
How do viruses reproduce?
Have to infect living host
What is the life cycle of bacteriophage T4?
Injects DNA into cell, synthesis begins, replication begin and host cell degrades, tails , heads appear and then breaks out of cell.
How was transduction discovered?
Two cultures were placed on minimal media, didn’t expect anything, some grew, transfer was unidirectional
What is the difference between specialised and generalised transduction?
Generalised is caused by phage DNA and specialized is caused by DNA shared between bacteria that already had phage DNA.
How to distinguish 3 parasexual using a u-tube?
Difference between lytic and lysogenic?
Lytic creates many bacteriophage lambda which results in them being released into the cell, lysogenic bacteriophage lambda is incorporated into the cell DNA via site-specific recombination. They can switch any time.
How does site-specific recombination work?
bacteriophage lambda breaks both DNA circular and straight bacteria creating an X, This results in the genes linking and X leaving.
U-tube experiment: is cell contact required for transformation, conjugation or transduction?
No, yes, no
U-tube experiment: is it sensitive to DNAase: transformation, conjugation or transduction?
yes, no, no
How does bacteriophage lambda DNA remove itself from DNA to create circular DNA?
attBP genes line up, creating a loop still connected to the bacterial DNA, circular breaks off the create phages to infect other cells.
How can bacteria DNA can be swapped via phages?q
When circular DNA is trying to remove itself, the loop can incorporate some DNA which can be incorporated in the next cell during site-specific recombination.
What are the three types of transposition and how do they do it?
Cut and paste (self-explanatory), transposition (mRNA to DNA) replication (replicated and inseted into new spot)
Can transposition occur in bacteria?
No
What are the IS elements?
Terminal inverted repeats q
How is DNA inserted during transposition?
DNA is cleaved, DNA inserted and filled creating duplicate of the target site.
How can transposition near each other create drug resistance (composite transposition?
IS elements are near each other, DNA is moved and inserted/
What are tn3 elements?
Larger than IS elements, multiple of them and create replicative transpose.
What does conjugative R plasmid?
Create antibiotic resistance through conjugative transfer
