Microbiology Review for Quiz 3 samir

Biobag

A device used to cultivate anaerobic organisms by creating an oxygen-free environment.

Palladium

Acts as a catalyst to remove oxygen in anaerobic growth setups.

Resazurin

An oxygen indicator that turns clear in the absence of oxygen and purple in its presence.

Gas Generator

Produces gas to eliminate oxygen, ensuring anaerobic conditions.

Clostridium sporogenes

An anaerobic bacterium that can grow in the absence of oxygen.

E. coli

A bacterium that consumes oxygen, allowing anaerobes like Clostridium sporogenes to thrive.

Neutrophiles

Bacteria that thrive around neutral pH (6.5-7.5).

Acidophiles

Fungi that thrive in acidic environments (pH 0-5.5).

Staphylococcus epidermidis

A bacterium tested for growth at different pH levels.

Saccharomyces cerevisiae

A yeast tested for growth at different pH levels.

Commensalism

A relationship where one organism benefits while the other is unaffected.

Antiseptics

Substances used on living tissues to reduce microbial load (e.g., alcohol).

Disinfectants

Substances applied to inanimate objects to kill microorganisms (e.g., Lysol).

Sterilization

The process that destroys all forms of microbial life.

Disk-diffusion method

A technique used to test the effectiveness of antiseptics and disinfectants by observing clear zones around disks.

Kirby-Bauer Disk Diffusion

A method that measures the susceptibility of bacteria to antibiotics using the zone of inhibition.

E-test

A method that provides quantitative data on the minimum inhibitory concentration (MIC) required to prevent bacterial growth.

Catalase Test

A test to detect the presence of the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen.

Simple Stain

A staining technique used to observe cell morphology by applying a basic stain like methylene blue.

Negative Stain

A staining technique that uses an acidic stain to observe bacterial capsules and cell morphology.

Colisure Test

A qualitative test that detects E. coli and total coliforms in water using color and fluorescence under UV light.

Compact Dry EC Test

A quantitative test for counting E. coli and coliform colonies using chromogenic substrates.

Membrane Filtration

A method that uses a 0.45µm cellulose filter to trap bacteria from water samples.

Ultraviolet Radiation

A method used to observe the lethal effects of UV light on microorganisms.

Osmosis

The movement of water across a membrane from areas of low solute concentration to areas of high solute concentration.

Halobacterium salinarum

An organism tested for tolerance to high salt concentrations (halotolerance).

Which organisms benefit, are harmed, or are indifferent to the association?

Two organisms were used in the Microbiology labs for commensalism are E. coli and Clostridium sporogenes The growth of E. coli in NB and FTM is all over the media but no growth of C. sporogeneses in NB and growth in FTM is at the bottom.

Which organisms were used in this experiment and how was their growth affected by the different pHs we used?

Staphylococcus cerevisiae: pH 5,Staphylococcus epidermidis: pH 7

What is the mutagenic effect of UV light on organisms?

formation of pyrimidine dimers

Which wavelength is most damaging to bacterial DNA?

260 nm=short wave

osmosis

diffusion of water across a membrane

hypertonic solution

It will shrink because water is leaving the cell where there is a hypotonic solution and entering the solution outside in a hypertonic solution. - shriveled cell

hypotonic solution

It will swell/expand because water is coming into the cell where it is hypertonic and leaving the hypotonic solution on the outside. (Water is moving from high concentration to a low concentration. - lysed cell

Define halophile. Give an example of the ones used in lab

growth at high NaCl concentration; Halobacterium salinarum

Define Halotolerant, example

growth at intermediate NaCl; Staphylococcus saprophyticus

Sterilization vs sanitization

sterilization is destruction of all life. Sanitization lower the amount of count.

Alcohol as a degerming agent, why

Dissolve the lipids on skin; expose microorganisms Denature the microorganism's proteins.

Bactericidal

Killing the bacteria.

Bacteriostatic

inhibits bacterial growth

Antiseptics

Solutions that destroy microorganisms or inhibit their growth on living tissue.

Disinfection

destruction of vegetative pathogens

Kirby-Bauer Disc-Diffusion method determines the

determines the MIC of the antibiotic by measuring the zone of inhibition.

What does MIC stand for?

minimum inhibitory concentration

What is zone of inhibition?

Area of clearing surrounding the antibiotic disc. No bacterial growth

The larger the zone

the greater the sensitivity to the antibiotic

If the zone of inhibition is large

You will only need a small amount of the antibiotic to prevent bacteria growth