Microbiology and Microscopy Review

These flashcards cover important concepts related to microscopy, microbial characteristics, and staining techniques from the provided lecture notes.

What is a compound light microscope primarily used to view?

Living or stained specimens such as bacteria, protozoa, fungi, and cells.

What is the maximum magnification of a compound light microscope?

About 1000 to 2000 times.

What type of microscope uses beams of electrons?

Electron microscope.

What is the magnification used with an ocular lens in a microscope?

10×.

What is the role of the stage in a microscope?

Holds the slide.

How does an iris diaphragm function in a microscope?

Controls light intensity.

Calculate the total magnification using a 40× objective lens and a 10× ocular lens.

400× total magnification.

What does the term 'parfocal' mean in microscopy?

The image remains nearly in focus when switching objectives.

Define resolution in the context of microscopy.

The ability to distinguish two points as separate.

What does resolving power measure?

Clarity of the image; higher means more detail.

What does a higher numerical aperture indicate?

Better resolution.

What is the first step in basic microscope use?

Start at 4× magnification.

What is the benefit of using oil immersion with a microscope?

Reduces light refraction and increases resolution.

What type of organisms are eukaryotes?

Organisms with a nucleus.

What type of organisms are prokaryotes?

Organisms without a nucleus.

Name the three common shapes of bacteria.

Coccus (spherical), Bacillus (rod-shaped), Spirillum/spirochete (spiral).

What are characteristics of protozoa?

Unicellular, heterotrophic, motile, no cell wall.

How do flagellates move?

Using flagella.

What kind of organisms are green algae?

Eukaryotic and photosynthetic.

What color results from chlorophyll in cyanobacteria?

Often blue-green.

What are the cell wall components of fungi?

Chitin.

What does Brownian movement refer to?

Random vibration of cells due to water molecule collisions.

How is a hay infusion prepared?

By soaking hay or plant material in water for several days.

What are the two main types of wet preparations?

Wet mount and hanging drop.

What is an advantage of wet preparations?

They allow observation of live cells.

What is the main difference between Brownian movement and true motility?

Brownian is random vibration; true motility is directed movement.

Describe the process for preparing a wet mount.

Place a drop of specimen on slide, lower coverslip gently, observe under the microscope.

What are key points of aseptic technique?

Work near flame, disinfect bench, wash hands.

What is a culture medium?

Nutrient solution for growing microbes.

Define inoculation in microbiology.

Adding microbes to media.

What does pellicle refer to in broth culture?

Surface growth.

What is the purpose of the quadrant streak plate method?

To isolate pure colonies from a mixed culture.

Identify one characteristic of bacterial colonies.

Shape, margin, elevation, size, texture, color, opacity, or odor.

What is a positive control in media?

Shows expected growth.

Why is agar considered an ideal medium?

It is not digested by most microbes.

What is the autoclave used for in sterilization?

To sterilize media by using high temperature and pressure.

What is the primary stain in acid-fast staining?

Carbol fuchsin.

What component of acid-fast bacteria is responsible for its characteristic properties?

Mycolic acids.

What distinguishes Gram-positive from Gram-negative bacteria in staining?

Gram-positive retains crystal violet; Gram-negative does not.

What color do Gram-positive bacteria appear after staining?

Purple.

What is the most critical step in the Gram staining process?

Decolorization.