Lab Week 05: Differential Stains II

A set of vocabulary flashcards covering essential terms and concepts related to differential staining techniques, including Gram Staining and Endospore Staining.

Gram Staining

A differential staining technique that classifies bacteria into Gram positive and Gram negative based on their cell wall structure.

Gram Positive

Bacteria that resist decolorization by 95% ethanol due to their thick peptidoglycan layer.

Gram Negative

Bacteria that do not resist decolorization by 95% ethanol and have a thin peptidoglycan layer.

Peptidoglycan

The characteristic compound found in bacterial cell walls that affects Gram staining.

Decolorizer

In Gram staining, this is usually 95% ethanol, which removes the stain from Gram negative bacteria.

Safranin

The counterstain used in Gram staining to make Gram negative bacteria visible.

Endospore

A dormant, highly resistant cell formed by some bacteria as a survival mechanism in nutrient-poor conditions.

Acid-fast Staining

A technique used to identify bacteria that do not stain well with Gram staining, particularly Mycobacteria.

Carbolfuchsin

The primary stain used in acid-fast staining to visualize Mycobacteria.

Thin Smear

A preparation technique for microscopy that ensures even staining and visibility of bacteria.

Control Cultures

Known bacterial strains used to validate Gram staining results, such as S.aureus and E.coli.

Vegetative Cell

The active form of a bacterial cell that can reproduce and grow, as opposed to its dormant endospore form.

Mordant

A chemical (like iodine in Gram staining) that helps to fix the dye on the cell wall of bacteria.

Mycolic Acid

A waxy substance found in the cell walls of acid-fast bacteria, such as Mycobacterium.

Waxy Outer Covering

A characteristic feature of acid-fast bacteria that makes them resistant to staining.