recombination conjugation transormation transduction

• eukaryotic occurs during meosis
• prokaryotic occurs when dna is transfered from donor to recepient cell

• donor dna alligns with recepient cell
• bases align and RecA catalyzes strands
• recipient chromosome contains new DNA

• requires direct cell to cell contact and opposite mating types
• donor cells carry plasmids
• recipient cells dont

• for gram - cells
• projections from the donor cell to get in direct contact with recipient cell
• for gram + cells
• produce sticky molecules to bring cells into direct contact

f+ cell (donor) - recombiation with chromosome produces a Hfr cell

f+ cell transfer plasmid to f- cell which results in a f+ cell

genes are transfered from one bacterium to another as naked DNA in a solution

• recipient cell takes up donor DNA
• bases align
• recombination occurs between donor and recipient DNA
• outcome is a genetically transformed cell

bacteria DNA is transferred from a donor cell to a recipeint cell inside a virus that infects bacteria; bacteriophage

• phage infect donor bacteria cell
• chromosome broken to peices so assembly of some bacterial DNAare packed and released after death of cell
• bacterial DNA phage infects new host cell
• recombination produces normally

gene always turned on

gene normall turned on but can be turned off in response to metabolic signal

gene is normally turned off but can be turned on in response to metabolic signal

regulatory mechanism that inhibits gene expression and decreases enzyme sysnthesis