Smear Preparation

goals for good smears:

adherence, no shrinkage, and thin smear

why is it important to limit the quantity of cells used to prepare a smear?

can't distinguish individual cell shapes, arrangements, and microstructures. Staining do not work well on clumped and layered cells in a smear because it becomes entrapped in clumps and prevents removal

for preparation of a smear on a slide, what is the purpose of heat fixation? what problems can arise when the slide is heated on the flame?

causes organisms to adhere to the glass so that they do not get washed off during staining. overheating can damage and dehydrate the cells causing them to distort in shape or shrink AND the glass can crack or shatter

how does smear preparations of cells from a liquid medium differ from preparation of cells from a solid medium?

cells from a solid medium are placed in a drop of water on the slide then smeared. this is not necessary for a loop of cells from a liquid culture

good smears are critical for discerning:

morphology of cells, arrangement, and internal structures

internal structures could include what time of structure found in Corynebacterium diphtheriae?

polyphosphate granules