Microbiology Lab Test 3

Handwashing

According to the CDC, this is the single most important means of preventing infection.

Transient Microbiota

The members of your normal microbiota that come and go and can be removed by washing with soap.

Resident Microbiota

Members of your normal microbiota that live on or in your body long-term, such as organisms in your hair follicles or sebaceous glands.

Emulsification

Process that soaps and detergents use to break up oils and fats into tiny droplets that can be washed away with water.

Saponification

Process of making soap, which involves heating fats or oils with a base like sodium hydroxide.

Antiseptics

A substance that prevents bacterial growth that is meant to be applied to living tissue.

Yes

Can soaps remove microbes without chemicals like triclosan added to them?

Genetics

Type of identification approach that involves analyzing the microbe’s DNA or RNA, such as real-time PCR or DNA microarrays

Immunologic

Type of approach that uses antigen-antibody reactions.

Phenotypic

Type of approach that looks at the microbe’s morphology and physiology.

Morphology Characteristics

Type of characteristics that involve cell shape, size, arrangement, gram-reactions, and presence of structures such as endospores, capsules, or flagella.

Cultural Characteristics

Type of characteristics that involve colony appearance, oxygen requirements, and temperature preference.

Physiological Characteristics

Type of characteristics involve the microbe’s ability to ferment certain sugars, enzymatic actions, and other by-products of metabolism.

Cytochrome Oxidase

Enzyme that the oxidase test looks for.

Cellular Respiration (Electron Transport Chain)

Aerobic process that cytochrome oxidase enzyme is a part of.

H2O

Product of oxidase.

Oxygen and Hydrogen

Substrate of oxidase.

Dark Purple/ Maroon

Color the disk turns into if the microbes is positive for oxidase.

Hydrogen Peroxide

Substrate for catalase.

Oxygen and H2O

Products of catalase.

Hydrogen Peroxide

Reagent that we add to the bacteria to test for catalase.

Bubbles

What the catalase reaction does when positive.

No effervescence

What the catalase reaction does when negative.

Uses nitrate as final electron acceptor

What bacteria that can reduce nitrate uses it for.

Nitrogen Gas

What does nitrate reductase reduce nitrate to?

Nitrate Broth

What is the media for the nitrate reduction test?

Nitrate A and Nitrate B

What the first two reagents that we add to test for nitrate reductase?

Red Color

What color the broth will turn if it is positive for nitrate reductase?

Denitrification

Some bacteria further reduce nitrite into nitrogen gas, in a process called what?

Zinc

To catch false negatives what chemical is added if the tubes don’t turn red with nitrate A and B?

Nitrite

What does the zinc change nitrate into?

Negative

If the tube turns red after adding zinc, what is the result for nitrate reductase?

Positive

If the tube still does not turn red after adding zinc, what does that mean?

Monosaccharides, Disaccharides, Polysaccharides

3 main forms of carbohydrates

Glucose, Fructose

Monosaccharides

Sucrose, lactose

Disaccharides

Starch, Cellulose

Polysaccharides

Ability to ferment a specific carbohydrate that is added to the media

What do we use phenol red broths to test for?

pH Indicator

Purpose of phenol red.

Collects Gas

Purpose of Durham tube in phenol red broth.

Positive for acid, yellow no gas; positive for acid and gas, yellow and gas; negative, red

Three possible results that may occur in phenol red broths.

Gram-Negative

Adding bile salts and crystal violet to MacConkey agar makes it selective for what type of bacteria?

Lactose

How is MacConkey agar differential, (what does it show the fermentation of)?

Lactose Fermentor, Red; Non Fermenter, Yellow

A positive and negative result for MacConkey agar.