Microm 302 Quiz 5

UW

How can bacteria acquire genetic material?

Conjugation, transduction, transformation

What is conjugation?

DNA transferred by direct cell to cell contact

What is transduction?

bacterial DNA is introduced by bacteriophage

What is transformation?

naked DNA taken up directly from environment

What is the term for a bacteria's ability to take up genetic content?

Genetic competence

What is acintobacter?

gram-neg, non-motile rod in soil/water and it is always naturally competent

What does naturally competent mean?

Capable of transformation at all stages of growth

When is bacillus competent?

During transition from exponential into stationary phase

When is E. coli competent?

Never

What is a genetic marker?

it is a gene encoding an observable trait thats absent in the recipient cell

What are prototrophs?

can grow on minimal media and contain only a single carbon source

What are auxotrophs?

Lack ability to synthesize one or more essential metabolites

Why do you heat a solution at 60C for 30 mins? Or just in heat?

To release DNA from cells -> naked DNA

What is DNase?

degrades DNA but doesnt harm cells

What is Trp+?

prototroph

What is Trp-?

Auxotroph

Will Trp- grow on minimal medium without tryptophan?

No

How can Trp- grow on a minimal medium?

If incorporates DNA from Trp+ donors, then will be able to make tryptophan and grow on minimal media

Will DNA grow on its own on TSY?

No

Will DNA, DNase, Trp- grow on minimal media?

Nope

Will DNase + Trp- grow on TSY?

ya since doesnt affect cells, affect free DNA

Will Trp- grow on TSY?

yeah

Will Trp+ grow on its own on either plate?

Yeah bc they are prototrophic

What causes cholera, typhoid fever, polio, dysentery

ingestion of fecally-contaminated water

How does fecally-contaminated media infect us?

colonize intestine and excreted and spread

What is an indicator organism?

indicate possibility of fecal contamination of water source

What are coliforms?

Gram-neg rods that ferment lactose w/ acid and gas within 48 hrs at 35C

How are coliform monitored?

MPN (most probable number) test. it gives a cell estimate if gas is produced. if results are high, it must be treated

What is Lauryl lactose broth?

Selective and differential medium with lactose, tryptone, lauryl sulfate (inhibits gram-neg cocci + gram-pos cocci/rods)

What is EMB agar?

selective and differential media with nutrient agar base (lactose+ eosin +methylene blue) and inhibits gram-pos anything and gram-neg cocci. So only gram-neg rods show. Lactose fermenting colonizers = pink/purple, bib-fermenters are colorless. E coli = green metallic sheen, Enterobacter aerogens dark center with no greeen sheen

How is luminescent bacteria working?

light produced thru chemical reaction, catalyzed by bacterial luciferace

What is quorum sensing?

Self-produced extracellular signal

What is autoinducer?

The self-produced extracellular signal used/produced in quorum.

why would double strength broth be used instead of normal?

If you put a sample with a lot of water in it, it will be diluted

What is IMViC?

indole, methyl red, Voges-proskaur and citrate biochemical tests