Lecture 4 Basic Microbial Morphology Flashcards
Name the two types of prokaryotic cells
Bacteria
Archaea
Name the most important differential staining method in microbiology
The Gram Stain
Example of gram postive bacteria
Staphylococci
Example of gram negative bacteria
Escherichia coli
Explain the gram stain mechanism
Differential lipid content of G+ and G- cell envelopes
Crystal violet-iodine complex forms within the cells (Blue colour)
What effect does alcohol treatment for gram stain method have on gram negative cell envelope
G- cell envelope has a high lipid content which is extracted by alcohol to permeabilise the memberane
What effect does alcohol treatment for gram stain method have on gram positive cell envelope
G+ cell envelope has low lipid
content and is dehydrated by
alcohol - making it impermeable
Name the bacteria that doesn’t stain using the gram stain method
Mycobacteria
Why don’t Mycobacteria stain using the gram stain method
have a high wax content in their cell envelope
Name the method used to stain mycobacteria
Ziehl-Nielson stain
Name the smallest known bacteria
Mycoplasmas
Why can’t mycoplasma use the gram stain method
They have no cell wall to stain
Name the types of bacterial shapes
Cocci(Spherical)
Bacilli(Rod shaped)
Curved or spiral shaped
Name the structure in a bacterial cell containing the bacterial genetic information
Bacterial chromosome
Other than bacterial genetic information what else is found in the chromosome
Plasmids
Name the structure that surrounds the cytoplasm
Cytoplasmic membrane
Name the rigid layer surrounding the cytoplasmic membrane
Cell wall
Name the structure that cover the cell wall and acts as a molecular sieve for gram negative bacteria
Outer membrane