CTE review unit 4

which bacterial wall contains teichoic acids

Gram positive bacteria

which includes an outer membrane?

Gram negative bacteria

Which is more resistant to antibiotics?

Gram negative bacteria

Which contains peptidoglycan

Both, gram positive has significantly more

Which of the following is NOT a chemical component of a bacterial cell wall?

Cellulose

Primary Stain: Crystal Violet, Color of Gram + cells

Purple

Primary Stain: Crystal Violet, Color of Gram - cells

Purple

Mordant: Iodine, color of Gram + cells

Purple

Mordant: Iodine, color of Gram - cells

Purple

Decolorizing agent: Alcohol-acetone, color of Gram + cells

Purple

Decolorizing agent: Alcohol-acetone, color of Gram - cells

Colorless (clear)

Counterstain: Safranin, color of Gram + cells

Purple

Counterstain: Safranin, color of Gram - cells

Red/pink

3 Parts of a microscope

Eyepiece objective lens, diaphragm

What is resolution

The ability to distinguish something. Higher magnification, the better resolution

what is the need for immersion oil

To see things more clearly

What’s brightfield microscopy

Observing an object in light. We use brightfield in class

What is darkfeild microscopy

Observing an object in darkness. Helpful when wanting to see unstained or transparent specimens (and not potentially dead too)

What is phase contrast microscopy (PCM)

Uses phase shifts to make dense areas darker or brighter

What is differential interface contrast microscopy (dicm)

It eliminates phase halos with converting refractive index gradients into amplitude (brightness). Gives a 3D color image.

What type of microscopy uses UV light

Fluorescence Microscopy

what is electron microscopy

it uses electrons for higher resolutions because of their shorter wave length, to see bacteria.

What is scanning electron microscope

it gives electron microscopy info about the surface of the specimen

what is transmission electron microscopy

It uses ultra-thin sections of samples

In Escheichia coli, escheichia is the

Genus

In Escheichia coli, coli is the

Specific epithet

three most common bacterial shapes

coccus (spherical), bacillus (rod-shaped), spiral (curved)

What bacterial shapes do we observe in the lab?

Coccus (spherical) and bacillus (rod-shaped)

What is the purpose of an isolation streak

To form single colony bacteria

What is confocal laser scanning microscopy

It uses laser light to illuminate one plane of a specimen at a time and produces a 3D image.

What is agar

jelly like substance used in culture bacteria

What is colony

group (like a bacteria colony)

What is LB

Growing culture (like LB agar, LB broth)

What is media

Substances (like liquid media)

Purpose of primary stain

Dye all bacterial cells

purpose of mordant

keep the stain dye trapped in petidoglycan layer

purpose of decolori

zing agent washes primary stain out. Mordant (aka Iodine) stays in pos. cell wall. Decolorizes neg. cell wall

purpose of counterstain

make cells visible. Turns neg pink, red, or orange. Pos. stays purple.

advantage of gram staining over simple staining

gram stain shows if the bacteria is + or -, simple just shows bacteria shape

potential pitfalls of gram staining

incorrect smear prep, over/under decolorizing, culture age, old reagents used, excessive washing/ drying

What is Lipopolysaccharides

A endotoxin

Which part of of negative cell walls are endotoxins

Lipopolysaccharides

Where are Lipopolysaccharides found

Outer membrane

which part of cell walls provide antigenic activity

Lipopolysaccharides

What diseases are typically found using acid fast staining

Tuberculosis and leprosy

Two bacterial genera that are acid fast include

microbacterium and norcandia

What are endospores

Structures that can survive extreme conditions

What genus of bacteria tend to form endospores

Bacillus

What special condition is required to push a stain into an endospore

Heat (steaming)