Term
| How do you convert millimeters to microns or microns to millimeters? |
|
Definition
Microns to millimeters: move decimal 3 to left.
Milliliters to microns: move decimal 3 to right.
Ex. 0.02 milliliters= 20µ |
|
|
Term
| What are 3 basic types of morphology? |
|
Definition
Cocci: never motile
Bacilli: often motile
Spirilla: always motile |
|
|
Term
| What are basic types of arrangement? |
|
Definition
| diplococci, streptococci, staphylococci, streptobacilli |
|
|
Term
| What is the purpose of a differential white count? |
|
Definition
| determines percentage of each type of white blood cells present in the blood |
|
|
Term
| How is a differential white count performed? |
|
Definition
| choose portion of smear with close proximity but little overlapping of red cells, use 100x with oil |
|
|
Term
| What is an artifact as it relates to microscopy? |
|
Definition
| a product (as a structure on a prepared microscope slide of artificial character due to extraneous (as in human) agency |
|
|
Term
| What is aseptic technique? |
|
Definition
| using practices/procedures to prevent contamination from pathogens |
|
|
Term
| How would you take a sample of bacteria from an agar slant using aseptic technique? |
|
Definition
| heat your loop, heat fix neck of tube, slant and collect from surface, transfer onto slide, reheat loop |
|
|
Term
| What is a benefit of heat fixing a smear? |
|
Definition
| enhances adherence of bacterial cells to the slide |
|
|
Term
| What are differential stains and how do they differ from simple stains? |
|
Definition
| differential stains allows us to tell the difference between microbes based on physiochemical characteristics, simple stains only show shape and size |
|
|
Term
| Which chemicals are used in the Gram stain and what is the sequence of steps? |
|
Definition
| Primary stain (crystal violet) reacts for 30 sec. and pour off, cover with iodine (mordant solution)-intensifier of primary stain- react for 30 sec., decolorize (95% ethyl alcohol) for 2-3 sec., rinse with distilled water, counter stain (safranin) for 1 min., rinse and blot dry |
|
|
Term
| What is an endospore and when would it be produced? |
|
Definition
| Endospores are usually triggered by lack of nutrients (gram positive bacteria) |
|
|
Term
| What chemicals are used in the endospore stain and what is the sequence of steps? |
|
Definition
| Primary stain (malachite green) and steam for 5 min., cool, decolorize (distilled water), counterstain (safranin) 45 sec., rinse with distilled water |
|
|
Term
| Which two genus of bacteria can have endospores? |
|
Definition
| aerobic bacillus, anaerobic clostridium |
|
|
Term
| Why can’t capsules be stained with conventional stains? |
|
Definition
| Capsular materials are water soluble and non ionic, negative staining needs acidic stain like india ink |
|
|
Term
| What is the benefit to a bacterium in having a capsule? |
|
Definition
| capsule provides microbial resistance to host phagocytosis |
|
|
Term
| What makes acid-fast bacteria different? |
|
Definition
| Mycobacteria is gram non-reactive and contains wax D (mycolic acid) cell wall that makes penetration by stains extremely difficult |
|
|
Term
| What chemicals are used and what is the sequence of steps of the acid-fast stain? |
|
Definition
| cover smear with primary stain (carbol fucshin) for 2 min., briefly decolorize by running acid-alcohol over, rinse with water but not directly on smear, counterstain with methylene blue for 30 sec., rinse, blot dry |
|
|
Term
| What is the function of the methylene blue? |
|
Definition
| counterstain, decolorized non acid fast cells will stain blue |
|
|
Term
| What are two diseases caused by mycobacteria? |
|
Definition
|
|
Term
|
Definition
| only one species, transferred pure colony by sterile loop into a broth or nutrient agar |
|
|
Term
| Define the terms sediment, turbidity and pellicle with respect to a nutrient broth culture |
|
Definition
Sediment- bacteria settles at bottom
Turbidity- (cloudy) bacteria throughout tube
Pellicle- thin, on top |
|
|
Term
| What is the purpose of agar? |
|
Definition
| agar is a nutrient medium used for the cultivation of microbes supporting growth of wide range of non-fastidious organisms |
|
|
Term
| What is the purpose of streak plating? |
|
Definition
| isolates bacteria, decreases amount of bacteria in culture |
|
|
Term
|
Definition
Gram positive retain primary stain (crystal violet)
Alcohol not decolorized, purple/pink
Bacilli- large, rod shaped, some form spores
Cocci- clusters of grapes (staphylococci) |
|
|
Term
|
Definition
Gram negative retain red counterstain (sanfranin)
Alcohol decolorized due to difference in cell wall structure, will be colorless.
Bacilli- tend to be short and single rod shaped
Cocci- individual short rods (coccobacilli) |
|
|
