BIO 205 Dr. Raymond Genetic Recombination

mutation

a permanent change in an organism's DNA

mutagen

A chemical or physical agent that causes a permanent change in an organism's DNA

point mutation

a change in one nucleotide of an organism's DNA

genetic recombination

an event in which one bacterium (the donor) donates DNA to another bacterium (the recipient) after which the recipient adds the donor bacterium DNA to its own, creating a new genetic combination.

carinogen

a cancer causing agent in humans

transformation

transfer and integration of DNA from a lysed donor bacterium to a recipient bacterium

transduction

transfer and integration of donor bacterium DNA to a recipient bacterium using a bacteriophage.

operon

a section of DNA that contains one or more structural genes and a regulatory gene that controls the transcription/translation of the structural genes.

operator site

where the repressor molecule binds to the operon

promotor site

region of DNA where RNA polymerase acts to begin transcription.

active repressor protein

attaches to operator to stop RNA polymerase from transcribing a set of genes.

Ames test

Test used to determine whether a particular substance is a mutagen of salmonella.

conjugation

transfer and integration of donor bacterium DNA to recipient bacterium DNA via cell to cell contact through a sex pilus

regulatory gene

The boss gene. It is always transcribed and translated

structural gene

a gene that codes for a product. Their transduction and translation is controlled by the regulatory gene.

inactive repressor protein

repressor protein of a regulatory gene that does not bind to the operator and allows RNA polymerase to transcribe and translate the structural genes.

lac operon

this operon is inducible and has an active repressor protein

tryp operon

this operon is repressible and has an inactive repressor protein

false

The structural genes on a lac operon are usually transcribed and translated. True or false?

true

The structural genes on a tryp operon are usually transcribed and translated. True or false?

1. Bacteriophage attaches to surface of bacterium

2. Phage injects it DNA into donor bacterium and donor bacterium DNA is broken apart

3. Phage DNA uses donor bacterium machinery to produce progeny phages

4. Packaging error occur creating some progeny (transducing phages) with donor DNA

5. Donor bacterium is lysed to release progeny. Transducing phage injects its DNA into recipient bacterium

What are the steps in transduction?

Only competent recipient bacteria can take up donor DNA

What is the limiting factor of transformation?

bacteriophage must be capable of infection both the donor and the recipient bacteria

What is the limiting factor of transduction?

requires 2 live bacteria, the bacteria have to stay together long enough via the sex pilus to complete the process

What are the limitations of conjugation?

F+

Bacterium with the fertility plasmid

F-

Bacterium without the fertility plasmid

Hfr (high frequency of recombination) bacterium

bacterium with fertility plasmid integrated into its DNA

Both are F+ (have the fertility plasmid)

What are the 2 resulting bacterium in an F+ with F- conjugation

HFR and F-

What are the 2 resulting bacterium in an HFR with F- conjugation

1. F+ donor connects to F- recipient via the sex pilus and the 2 bacterium are drawn closer together.

2. 1 strand of the F+ plasmid DNA is transferred to the recipient through the pilus

3. The donor and recipient each synthesize a complimentary DNA strand for the fertility plasmid

4. Both bacteria are now F+ and can produce a sex pilus

What are the steps in an F+ with F- conjugation

1. HFR and F- bacterium connect and are drawn closer via a sex pilus

2. DNA transfer begins in the middle of the F plasmid DNA but the connection is broken before all the F plasmid DNA can be transferred

3. The recipient bacterium gets some F plasmid DNA (but not the gene for the sex pilus) and some donor bacterium DNA and integrates it into its own DNA. F- recipient is still F-

What are the steps in an HFR with F- conjugation

true

True or false, transformation, transduction and conjugation increase antibiotic resistance