BISC310 Ex2 Commom Methods to Control Microbial Growth

your health

mental state

life expectancy

your microbiome can have drastic effects on what 3 things?

soap's amphipathic molecules

What molecule makes soap effectivee

an amphipathic molecule

Each molecule has a hydrophilic polar head region and a hydrophobic tail region

repelled by water

attracted to oils

in an amphipathic molecule, the tail is repelled by what? But attracted to what?

micelles

when introduced to an aqueous environment, soap molecules will create spherical structures called ____________

oils, dirt, microbes

What 3 things do micelles trap?

Get washed away (done the drain)

After the micelles trap the 3 components inside, where do they go when introduced to aqueous envrionment?

No, soap simply remove them from the skin's surface by washing the micelles away

Do basic soaps lyse or kill bacteria?

due to their adverse affects on human health, the environment, and their propensity for creating drug-resistant bacteria

what 3 things caused for antibacterial soaps to be banned by the FDA

No

Are there conclusive results that say additives to soap are more beneficial than plain soap?

hand sanitizers lyse or kill microbes from skin, instead of removing

How are hand sanitizers different then handwashing?

Gram-positive bacteria

Gram-negative bacteria

Enveloped viruses

Alcohol-based hand sanitizers are bactericidal or viricidal toward what 3 things.

denaturation and coagulation of proteins

hand sanitizers betweeen concentrations of 60-90% alcohol cause cells to lysis through ____________ and ____________ of proteins

90%

alcohol concentration higher than what % have decreased efficiency?

only active against vegetative cells

unable to destroy spores

alcohol is only active against what cells? Therefore, what are they unable to destroy

30 seconds or longer

To use hand sanitizer effectively you should leave a large enough quantity to leave the skin wet for how long?

60%

Alcohols are only effective of they contain at least how much alcohol?

Tryptic Soy Agar (TSA)

General-purpose nutritive medium used to support the growth of a wide range of non-fastidious and fastidious bacteria, as well as some fungi.

Soybean and casein *provide peptides, amino acids, and other nitrogen-containing compounds* to support growth.

Sodium chloride helps *maintain* the cells' *osmotic balance*

In TSA plastes how do soybean and casein digests support microbial growth, and what role does sodium chloride play in the medium?

TSA

Due to rich nutritive compositions, this is commonly used as a basal medium for enriched media, such as sheep blood agar (SBA)

Fastidious bacteria

These types of bacteria require additional growth factors or specific nutrients to support growth and therefore require supplemented media.

Whether they are *chemically defined or complex*

What is another important way to describe microbiological media?

Chemically defined media

Media where all the chemical components and their exact concentrations are known

Complex media

Media where some ingredients are naturally derived (extracts and digests) and their chemical composition is unknown

TSA and NA

What are 2 examples of complex media?

microbial growth,

types of organisms cultivated,

colony appearance (size, margin, texture, and pigmentation)

Choice of media can affect what 3 things?

hydrophilic polar head

and

hydrophobic tail

What's the makeup of the tail and head regions of an amphipathic molecules?

False

handwashing removes them with micelles

hand sanitizers lyse them

True of False: handwashing and hand sanitizers both removes microbes, oils, and dirt from skin

60-90%

What % concentration of alcohol in hand sanitizer is necessary to cause cell lysis?

False --> decrease efficiency

True or False: Hand sanitizers with >90% are more efficient.