Exam 2

Plasmid

100

Where is the Rep protein encoded?

Plasmid

200

What is the purpose of alpha-complementation?

To see if a transformed bacterial colony has plasmid+ insert of not

300

What is a replicon?

DNA molecules that can replicate autonomously in the cell (plasmids, phages DNA and chromosomes)

400

What does it mean to cure the plasmid?

Bacteria loses plasmid during replication.

500

Functions of the Ori regions?

1) Host range: narrow and braod 2) Regulation of copy number 3) Incompatibility 4) Plasmid replication and control mechanism

Transfer of Genetic Information

100

Name some ways that can result in heritable changes in the genome of bacteria

1) genetic transfer 2) recombination 3) plasmids 4) transposons

200

Name three ways of genetic transfer:

1) Conjugation – F’ fertility factor 2) Transduction/Transfection – virus vector 3) Transformation – direct uptake of naked DNA by cell

300

Significance of oriT (origin of transfer) in bacteria?

This is where the F’ is nicked to start rolling circle replication

400

What is prophage?

state of the phage in a lysogen in which the phage DNA is integrated into the chromosomal DNA of the bacterium or replicates as plasmid

500

2 ways to help transformation?

1) Electrocompetence: strip cations and run electric current which results in holes in the cell membrance allowing DNA to leak in 2) Calcium competence: destabilize cell membrane by flooding outer membrane with calcium and inducing heat shock, causing DNA to leak in

Regulation of Gene Expression (1)

100

Presence of glucose will result in expression of genes for lactose T/F?

False - presence of glucose will result in suppression of genes for lactose

200

Lac operon has how many binding sites?

2 binding sites: DNA & Protein

300

What happens to Adenylate cyclase (AC) activity and cAMP levels when glucose is NOT present?

AC is expressed which means it synthesizes cyclic AMP (cAMP) from ATP, resulting in HIGH levels of cAMP

400

Difference between the functions of AraC and Lac repressor?

AraC can act as a repressor and an activator, whereas Lac repressor only inhibits the expression of the lac operon

500

Difference between trans-acting and cis-acting sites?

trans-acting sites: if a DNA sequence can act from afar on another DNA sequence. If it can, then it is a diffusible protein since they act from afar cis-acting sites: if a DNA binding site needs to be near other DNA sites (such as coding sequences) in order to function, since they need to be next to another DNA to work.

Regulation of Gene Expression (2)

100

What is CAP responsible for?

CAP is responsible for the global regulation of carbon utilization

200

Define catabolic repression

Mechanism for ensuring that the cell will preferentially use the best carbon and energy source

300

What happens to sigma 32 when there isn’t enough DnaK?

Sigma 32 will increase because it is not being degraded by DnaK

400

Difference between major and minor regulon?

Major regulon: sigma-32 regulon - consists of about 30 genes. Minor regulon: sigma-E regulon - consists of about 3 genes.

500

Where is the CAP binding site located in CLASS II CAP-activated promoters?

CAP binding site overlaps the promoter

Miscellaneous

100

2 types of plasmid replication?

1) Theta replication 2) Rolling circle replication

200

What is a selectable marker?

Gives the bacteria with plasmids a selective advantage in specific media

300

What does lacI code for?

Regulatory protein, lactose repressor

400

Specialized transduction requires a phage that uses the lysogenic cycle for reproduction. T/F?

True

500

Which of the two are subject to catabolite repression? a) Ara b) Lac operon c) both

c) both