Lab Quiz 4 Flashcards

1
Q

How do you calculate Original Cell Density?

A

Colony Forming Units / (Dilution X Volume of sample)

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2
Q

What is Beta Hemolysis?

A

Complete lysis of blood cells

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3
Q

What is Alpha Hemolysis?

A

Partial lysis of blood cells, turns the agar green

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4
Q

What is Gamma Hemolysis?

A

Bacteria can grow on the plate, but can’t destroy any red blood cells

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5
Q

When is Blood Agar used in real life?

A

Strep tests

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6
Q

What is bacteriocidal?

A

Capable of killing bacteria

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7
Q

What is bacteriostatic?

A

Capable of stopping bacterial growth

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8
Q

Why doesn’t penicillin kill gram negative bacteria?

A

Gram negative bacteria have an outer membrane outside of the peptidoglycan that penicillin can not cross.

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9
Q

What is a Fomite?

A

Any object or substance capable of carrying and transferring an infectious disease. Ex: Skin, hair, clothing

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10
Q

What is a Vector?

A

Any agent or person capable of carrying and transferring an infectious disease. Ex: person, mosquito, animal, microorganism

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11
Q

What is a Common Source Epidemic?

A

All victims acquire the infection from the same source like water or ventiliation

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12
Q

What is an Index Case?

A

The first case. The first person to contract the disease.

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13
Q

What is Propagated Transmission?

A

The disease is transferred person to person

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14
Q

How do you calculate Incidence Rate?

A

new diseases in time period / size of at risk population

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15
Q

How do you calculate Point Prevalence?

A

existing cases at a point in time / size of at risk population

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16
Q

What is GYEA?

A

Glycerol Yeast Extract Agar

17
Q

What does GYEA grow?

A

Actinomycetes bacteria. Actinomycetes are soil decomposers

18
Q

What did the NA select for?

A

Broad range of bacteria but not fungi

19
Q

What was added to NA to inhibit fungal growth?

A

Cycloheximide. It blocks eukaryotic biosynthesis

20
Q

What is SDA?

A

Sobouraund Dextrose Agar

21
Q

What did SDA grow?

A

Fungi, no bacteria

22
Q

What was aded to SDA to inhibit bacterial growth?

A

Penicillin and streptomycin

23
Q

What are coliforms?

A

Lactose fermenting, rod shaped, gram negative bacteria

24
Q

How are coliforms detected on the membrane filter?

A

Metallic green color

25
Q

What is Endo Agar?

A

Encourages gram negative growth and inhibits gram positive growth.