Aseptic Technique, Streak Plate, & Simple Stain

These flashcards focus on key concepts and procedures related to aseptic technique, streak plating, and simple staining in microbiology, which are essential for understanding proper laboratory practices and microscopy.

What is the goal of aseptic technique?

To transfer a bacterial sample without introducing any contaminating microorganisms.

What method is used to obtain a pure culture from a mixture of microorganisms?

The streak plate method.

What does streaking create on the agar surface?

A serial dilution of the sample where individual cells are deposited.

What can arise from a single bacterial cell on an agar plate?

A colony.

What three characteristics can be used to describe colonies?

Whole colony, Margin, and Elevation.

What are two forms used to describe the whole colony?

Circular and Irregular.

How can the margin of a colony be described?

Entire or Undulate.

What are the two types of elevation of colonies?

Umbonate and Convex.

What is a simple stain?

A technique that uses a single stain to observe basic features of bacteria.

What staining agent is commonly used in simple stains?

Crystal Violet.

What characteristics can be determined using simple stains?

Morphology, arrangement, and size.

What materials are needed for the streak plate exercise?

Nutrient agar plates, broth culture of S. aureus, broth culture of B. subtilis, water blanks, and toothpicks.

What should be labeled on the bottom of the nutrient agar plate?

Your name, bacteria name, and initials.

What is the first step in the streak plate method?

Sterilize your loop and obtain a loopful from the bacterial stock.

What direction should you drag your loop in the streak plate method?

Across the bacteria into the next quadrant, zig-zagging down.

At what temperature is the agar plate incubated?

37°C.

What is the difference between form and margin in describing a colony?

Form refers to the overall shape, while margin describes the outer edge appearance.

What should be drawn on the microscope slide for the simple stain exercise?

A large rectangle, circle, and triangle.

When scraping your mouth for the smear, where should you focus your scraping?

Where your teeth meet your gumline.

What is the purpose of heating the slide during the simple stain procedure?

To heat fix the sample.

What should be done after the Crystal Violet stains the slide?

Gently wash off the excess stain with tap water.

What should be used to observe bacterial specimens on a microscope?

A microscope, starting at 4x and going up to 100x.

What is observed at 100x magnification?

Using oil immersion.

What is the gram classification of Staphylococcus aureus?

Gram positive.

What should be done with the microscope slide before adding the stain?

Allow the smears to air dry.

What is the outcome of observing teeth scrapings with a simple stain?

Identify the morphology and arrangement of bacteria.

How do you properly sterilize a loop in the laboratory?

Pass it through the flame of a Bunsen burner.

What shape is the area designated for S. aureus on the slide?

A circle.

What shape is the area designated for B. subtilis on the slide?

A triangle.

How long should Crystal Violet stain the specimens?

For 1 minute.

What supplies are used to clean the microscope slide after staining?

Kimwipes.

What does the streak plate method help to ensure about the culture?

That it is pure, with single colonies arising from isolated cells.

What is the appearance of colonies observed for morphology?

Varies based on the type of bacteria and conditions.

What should be done after spreading the bacteria in the first quadrant?

Re-sterilize your loop.

What is meant by 'umbonate' in terms of colony elevation?

A raised, dome-like elevation.

What are the visual characteristics of a colony that can be described under 'margin'?

Sharp or scalloped edges.

What should you do with your agar plate after the streaking process?

Place it upside down in the incubation pan.

Why is it necessary to re-sterilize your loop after each quadrant?

To avoid cross-contamination between quadrants.

What characteristics make Crystal Violet a useful stain?

It binds to cellular structures, allowing morphological observation.

In which part of the cytological preparation do you apply the heat fixing?

After air drying the smears.

What does the term 'irregular' refer to in colony morphology?

An asymmetrical, uneven shape.

How are arrangements of bacterial cells classified?

Based on how cells group together.

What is indicated by the term 'gram positive'?

Bacteria that retain the crystal violet stain and appear purple.

How can colony morphology help in identifying bacteria?

By analyzing shape, texture, and color.

What technique should you use to take a loop full of bacteria?

Aseptic technique.

What is the purpose of the labeling on the agar plate?

To keep track of which bacteria is being used.

What tool is used to spread bacteria on a microscope slide?

A sterile loop or a toothpick.

What is important to note about all microbes with a simple stain?

They will all appear the same color.

How does one obtain a loopful of water for the slides?

By adding a loop full of water to the slide.