module 3 Flashcards
compare prokaryotes and eukaryotes
Prokaryotes:
-Mostly circular chromosomes, no nucleus
-No organelles
-Peptidoglycan cell walls
-Binary fission
Eukaryotes:
-Mostly linear chromosomes
-Orgnaelles
-Polysaccharide cell walls (if present) chitin, cellulose
-Mitosis
What are common bacterial shapes, arrangements and groupings
bacilli cant cluster, always dividing along shortest side
Describe cell wall structure
Describe gram positive cells
Describe gram negative cells
glycocalyx
What are bacterial smears and stains
What is the gram stain process
What are gram staining difficulties?
-Older cultures have weak cell walls (lose crystal violet)
-Older solutions may not work properly (especially iodine)
-Decolorization timing is critical
-Excessive counter stain can displace crystal violet
-Some bacteria are gram variable (cells may stain partially)
What is aseptic technique?
-Prevention of contamination when cultivating microorganisms
-Requires diligence as bacteria, yeasts, molds and otehr organisms are virtually everywhere
Describe acid-fast stain
Positive = pink, negative = blue/purple
Describe glycocalyx
Describe negative stain
Describe flagella
Describe endospores
Describe endospore staining
What are the physical factors affecting bacterial growth
-Temperature
-Salinity
-pH
-Nutrients
What are the temperatures in which certain bacteria grow
What are the salinity and pH in which certain bacteria grow
What are the chemical nutrients required for certain bacteria to grow
why is oxygen toxic
What are the O2 requirements/sensitivities of bacteria
What is a complex media
Not aware of every chemical in the media
-partially digested beef
-Ground up dried yeast
What is a defined media
Every chemical in the media is known and quantified
-Sugars, amino acids and inorganic nutrients
-Can be tailored to requirements of one species
-Can even add or control presence of trace elements
What are the different types of media?
