Cells that are round have the following morphology:

Coccus

Cells that are rectangular in shape have the following morphology:

Bacillus

Long thing flexible cells shaped like a corkscrew, containing axial filaments, have the following morphology:

spirochete

Two round cells that are physically stuck together have teh following arrangement:

diplococcus

several rectangular cells that form a chain have the following arrangement:

Streptobacillus

Cells shaped like a comma have the following morphology:

Vibrio

A simple staining employs the use of a ___ charged dye to stain cells that are ___ charged:

Positively, Negatively

True/False:

The purpose of a heat-fixation is to kill the organisms, they will adhere to the slide, and it will stimulate motility by activating flagella

False

Smears should never be heat-fixed while they are still wet because

creates living aerosols

True/False:

Simple staining is not very useful for examining living organisms or for testing an organisms' motility.

True

True/False:

When performing negative staining, it is important to heat fix the microbial smear prior to staining.

False

Cells that are wavy, large, and rigid, with external flagella, have the following morphology:

Spirillum

After performing a negative stain, for the most part, how will the cells look?

colorless

Four or more bacilli shaped cells that are arranged in a long chain:

Streptobacillus

Multiple Choice:

Living cells have a net (negative OR positive) charge and will (attract OR repel) negatively charge stains.

Negative, Repel

True/False:

Gram negative cells have a thick cell wall and are surrounded by an additional layer of lipid.

False

When Gram-negative cells lyce in KOH test, what cellular material causes the characteristic "stringing"?

Chromosomal DNA

In the Gram stain, the primary stain is:

Crystal Violet

If the iodine step is missed, Gram positive cells will appear ___ at the completion of the protocol:

Red

True/False:

Gram-positive cells are susceptible to Vancomycin while most Gram-negative cells are resistance.

True

Bacterial cells that are actively undergoing metabolic processes and binary fission are referred to as:

Vegetative

the two clinically significant genera that are capable of producing endospores:

Bacillus, Clostridium

Why is steam used during endospore staining?

Heat i necessary for driving stain into the spore coat

In the capsule stain, what stain serves as the negative stain?

Congo Red

In the capsule stain, what stain serves as the positive stain?

Maneval's

Four chemical elements essential for comprising 98% all living things:

Carbon (C), Hydrogen (H), Oxygen (O) and Nitrogen (N)

• Phosphorus (P) and Sulfur (S) are also necessary

What are the optimum temperatures at which all living organisms grow?

Body temperature 37*C

Room temperature 20-27*C

Refrigerator temperature 4-10*C

Freezer temperature -20*C

Note: Some microbes grow above or below these temperatures

Members of Microbial world

Living Members:

Nonliving Members:

Living: bacteria, protozoa, fungi, algae, and parasitic worms

Nonliving: viruses, viroids, and prions

Media (singular: Medium)

the food that is used to culture microorganisms

Physical Factors that affect Growth of Microorganisms:

1. Temperature - there is an optimum temperature for all living organisms to grow

2. pH - reflects the relative acidity/alkalinity of a solution (0 [most acidic] to 14 [most alkaline]) all living organisms have an optimum pH
- Human Blood has a pH of 7.2-7.4

3. Oxygen gas: only 50% of all microorganisms require oxygen
- In fact, even trace amounts of oxygen can be deadly to some microbes

4. Salt concentration: Controls the amount of water available to a cell (also the same with sugar)

Isotonic

Define: Solute concentration is the same outside & inside the cell

What happens: Stays the same

Why: Equilibrium already reached

Hypertonic

Define: Solute concentration greater outside the cell than inside the cell

What happens: Crenates (shrinks)

Why: water rushes out of the cell

Hypotonic

Define: Solute concentration less outside the cell than inside

What happens: Lysis (swells)

Why: water rushes into the cell

Types of media

1. Solid: Agar

2. Liquid: Broth

3. Semisolid: contains lower % of agar than solid media (bit runny)

Agar

an algal extract that acts as a solidifying ingredient when added to microbial media

• no nutritional substance

the media is mixed , heated to boiling, & sterilized into an autoclave. Once sterile, molten media is put into sterile Petri dishes or test tubes.

Why not use gelatin instead of agar?

Gelatinized media turns to a liquid at 37* (room temperature) and agar does not. Aldo some organisms produce enzymes that turn gelatin into a liquid.

Most bacteria divide by a process called...

Binary fission

• Binary - 2
• Fision - to split

Generation time

the time it takes for a single cell to split into two new cells

When you start to see one little colony approximately how many cells need to be in the colony for you to be able to "see" it?

About 1 million

Descriptive terms for colonies grown on a solid surface

1. Whole colony shape
2.Margin (edge of the colony): Swarm - leaving an opaque pattern of waves across the medium (sometimes they do this)
3. Elevations: What the colony looks like from the side (how high off media
4. Size: measured in millimeter (mm) Punctiform- colonies of enormous size
5.Texture: wet, mucoid, erose (dry, crusty) granular, opaque (almost see through them), shiny, and dull
6. Pigment: may be within the colony or diffusing away from the colony

NA Agar

Bacterial

SDA agar

Fungal

Bacterial Configurations:

1 Round,
2 Round with scalloped margin,
3 Round with raised margin,
4 Wrinkled,
5 Concentric,
6 Irregular and spreding

Fungal Configurations

1 Filamentous,
2 L-Form (darker mass in middle)
3 Round with radiating margin
4 Filiform
5 Rhiziod
6 Complex

Bacterial Margins:

1. Smooth (entire)
2. Wavy (undulated)
3. Lobate
4. Irregular (erose)

Fungal Margins:

1. Ciliate
2. Branching
3. Wooly
4. Thread-like
5."Hair-Lock"-like

Bacterial Elevations:

1. flat
2. raised
3. convex
4. Drop-like

(5.) Umbonate ??

Fungal Elevations:

1. Hilly
2. Ingrowing into medium
3. Crateriform

(4.) Umbonate ??

Ring

Film of growth clinging to the test tube at the liquid-air interface

Pellicle

A membrane or scum-like structure that floats on the top of the liquid media

Sediment

Organisms may settle and grow, forming a layer at the bottom of the tube.

Folcculent

Visible chunks/flakes/broken particles supended throughout the broth medium

Uniform Fine Tubridity

Turbidity means "cloudy"

Why might an organism fail to grow?

bad culture, loop was too hot when trying to transfer, or the nutrients weren't right for the the organism

Why might two different organisms show exactly the same growth features even if they are not supposed to?

Cross contamination

Why is it necessary to use a negative control?

It make it easier for a base-line comparison

What is meniscus?

When water beads or pools up on a surface

what growth patterns are similar or different among the organisms tested?

Bacillus subtilius - Pellicle (the only one that had it)

Everything had sediment

Is it possible for an organism to produce more than one growth pattern in the same tube?

Yes

A film of growth on teh surface:

Pellicle

Even cloudiness

Uniform fine turbidity

Growth adhering to the glass at the liquid/air interface:

ring

Suspended flakes or particles:

Flocculent

A layer of growth at the bottom of the broth

Sediment

#A is the Ocular

#B is the rotating nosepiece

# 3, 4, 5 are the objectives

#11 is the mechanical stage

#I is the stage adjustment knobs

#8 is the Substage light

#14 is the Base

#10 is the Arm

#G is the Coarse adjustment knob

#H is the Fine adjustment knob

#K is the power switch

#7 Condenser

• Connected to the condenser is the iris diaphragm lever which controls the light that filters through

Working distance

The distance between the slide and the objective lens

Calculating total magnification:

Ocular 10X 10X 10X 10X
Objective (4X) (10X) (40X) (100X)
Total: 40X 100X 400X 1000X

Refraction:

The bending of light as it passes from one medium to the next

• The amount of available light decreases w/ magnification because the field of view becomes smaller and smaller
• At 1000X, there is not enough light available to see the specimen clearly w/o the use of immersion oil. Therefore, immersion oil must be used w/ the 100X objective

what happens to the field of view as the magnification increases?

it decreases

What happens to the light when the iris diaphragm lever is moved to the left (increases or decreases)? Moved to the right (increases or decreases)?

Increases, Decreaes

What happens to the contrast when the iris diaphragm lever is moved the left (increases or decreases)? Moved to the right (increases or decreases)?

Decreases, Increases

True/False:

The Coarse adjustment knob may be used with all 4 objective lenses.

False

True/False:

The fine adjustment knob may be used with all 4 objective lenses

True

What part of the microscope should be used to center the speciment in the field of view?

Stage adjustment knobs

What part of the microscope can be adjustment to increase or decrease the contrast?

iris diaphragm lever

True/False:

Immersion oil helps to increase the refraction of light as it passes through the glass specimen slide

False

If the power of the ocular is 5X and the total magnification is 200X, what is the power f the objective? Justify your answer by showing your work.

200/5 = 40

40X

If the power of the ovular is 10X and the power of the objective lens is 45X, what is the total magnification? Justify your answer by showing your work

45X*10X=450X