The flashcards below were created by user
on FreezingBlue Flashcards.
Explain the term aseptic techniques and sterile conditions and why they are important in microbiology
Proper aseptic technique prevents contamination of cultures from foreign bacteria inherent in the environment.
thus interfering with the lab results.
Essential for isolation of a single species of microorganism from a mixed culture to obtain a pure culture.
Prevents microbes used in the laboratory from accidentally being released into the environment and/ or infecting people working in the laboratory. This is especially relevant when pathogens are being handled.
Bacterial structure the gram stain is based on
Gram staining is based on the ability of bacteria cell wall to retaining the crystal violet dye during solvent treatment.
The cell walls for Gram-positive microorganisms have a higher peptidoglycan and lower lipid content than gram-negative bacteria. Bacteria cell walls are stained by the crystal violet.
Iodine mordant: to form the crystal violet-iodine complex so that the dye cannot be removed easily.
three differences between gram + and gram _ bacteria
Gram-positive cell walls contain a thick layer of peptidoglycan that encircles the cell. Gram-negative cell walls contain a thin layer of peptidoglycan between the cytoplasmic membrane and the outer membrane.
-: presence of outermembrane, high lipid content
key incubation conditions when culturing bacteria
Keep plates at room temperature or incubate at 20-25 °C for 2-3 days.
morphological features of bacteria seen on gram stained slide