Micro smear quiz 7

Select the statements that represent goals in correct smear preparation.

- The cells must be heat fixed to the slide to prevent removal when stain is washed off the slide. - It is important to minimize any artifacts or distortion of the cells for accurate viewing after staining. - Smears must be thin to allow for observation of single cells.

Order these statements to indicate correct aseptic procedure for removing organisms from a culture for application to a slide.

1. Heat inoculating loop and wire to red-hot. 2. Remove the cap of the culture tube and flame the mouth of the tube. 3. Remove a loopful of organisms from the culture. 4. Flame the mouth of the culture tube. 5. Return the cap to the culture tube. 6. Place organisms onto the slide in the center of the target circle. 7. Flame the loop red-hot before setting aside.

If heat fixation step is skipped in the smear preparation process, what might occur?

Cells may wash off during staining.

It is important that the smear is thick in order to ensure that the stain will be retained on the slide.

False

It is important that the smear is thick in order to ensure that the stain will be retained on the slide. T/F

False

When removing a sample from the plate, you should make sure that you remove an entire colony with your loop to make sure you have enough to spread across the slide

False

What should be done first when creating any new smear slide?

Label the slide with the name of the organism

Why is it important that the cells are not distorted during the smear preparation and staining process?

Microscopic examination can show their true shape and arrangement if done correctly.

What is heat fixation?

Passing the slide through the flame of a burner several times after the smear has completely dried

What may occur if you did not dissipate heat prior to removing your sample?

The cells may be distorted on the slide.

If smears are too thick, what might happen?

The smear might stain incorrectly.

How long should a slide be exposed to the heat for the fixation step?

Three brief passes through the flame

What is the purpose of heat fixation?

To kill and adhere cells to the slide

A sample from a liquid medium would not require the initial water drop.

True

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

Water is applied to the slide before emulsifying cells from a solid medium.

Before heat fixation, a wet smear of bacterial cells on a slide must first be

air dried