Bios 260 Final Exam - –Answer Transfer of DNA from one bacterium to...

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Bios 260 Final Exam

• What is horizontal gene transfer? What are the 3 types of horizontal gene transfer?

–Answer Transfer of DNA from one bacterium to another. The 3 types of horizontal gene transfer are transformation, transduction, and conjugation.

• What is a replicon and why is it important for vertical gene transfer of traits gained by

recipient cells in horizontal gene transfer?–Answer A replicon has its own origin of replication, so it will be replicated by DNA pol.Both plasmids and chromosomes are replicons!This is important because is a DNA fragment is transferred from donor to recipient cell, that trait will only be passed on to cell progeny if that fragment is integrated into a plasmid or chromosome. AKA if the fragment ends up in the genome. Integration requires the process of homologous recombination.

• What is genotype?

–Answer the sequence of nucleotides in DNA

• Define

–Answer donor cell –Answer The cell donating DNA

• Define

–Answer recipient cell –Answer the cell receiving the DNA. The recipient cell must be in a physiological state called competence to take up exogenous DNA.

• Define

–Answer homologous recombination, non-homologous recombination 1 / 2

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–Answer Ho- mologous recombination is a process where a cell replaces a segment of DNA with another segment that has a similar sequence.Non-homologous recombination is the same as homologous except the dna seq- ment does not need to be very similar in sequence to the segment it replaces in the genome.

• Define

–Answer competent cell –Answer the specific physiological state wherein bacteria (recip- ient cell) can uptake DNA.Some bacteria can receive DNA from any source, while others will only take DNA from closely-related species, as its 'recognized' based on nucleotide sequences.Some bacteria are always competent, while other cells have competence under tight control; gaining competence only when population reaches critical density (quorum sensing) or when certain nutrients become scarce.

• Define

–Answer f+ cell and f- cell,

• coli most widely studied bacteria that exhibit these plasmids.

–Answer F=Fertility –Answer F+=has F plasmid, will act as donor in conjugation.F-=cell lacks F plasmid, will act as recipient in conjugation.The F plasmid ONLY codes for the traits required to transfer the F plasmid –Answer F pilus, enzymes

• What is transformation?

–Answer a form of horizontal gene transfer; the bacterial DNA is transferred as "naked" DNA when a recipient cell takes up this naked DNA from the environment.

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