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Microbiology > Chapter 9 Study Guide > Flashcards

Chapter 9 Study Guide Flashcards

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Biology 101 flashcards
1
Q

They do not use oxygen because they usually have a fermentative metabolism

Does not use oxygen but tolerates it’s presence; grows anaerobically regardless of oxygen levels.

A

Aerotolerant anaerobes

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2
Q

Grow via fermentation or anaerobic respiration when oxygen is not available

Also, thrive in the presence of oxygen

Can grow with or without oxygen; prefers oxygen but can switch to anaerobic metabolism is oxygen is absent

A

Facultative anaerobes

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3
Q

Require oxygen concentration lower than air

A

Microaerophiles

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4
Q

Microorganisms that grow optimally at pH less than 5.55

Examples: sulfur oxidizing sulfolobus spp, ferroplasma, lacobacillis

Have optimal growth at ph of 3

A

Acidophile

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5
Q

Lactobacillus bacteria which are an important part of the normal microbiota of the vagina are

A

Acidophile

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6
Q

Most bacteria are _____, meaning they grow optimally at a ph within one or two ph units of the neutral ph of 7

A

Neutrophile

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7
Q

Prokaryotes reproduce asexually using

All daughter cells are genetically identical

Genetic variability is achieved by horizontal gene transfer

A

Binary fission

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8
Q

Are microbial communities attached to surfaces

Living
Non living

They may contain different species
An extracellular matrix of polysaccharides holds them together

Benefits include shared nutrients
Resistance to mechanical stress
Protection from immune system
Protection from drugs

A

Biofilms

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9
Q

Another curious example of cell division in prokaryotes, reminiscent of the live birth in animals, is exhibited by the giant bacterium epulopiscium. Several daughter cells grow fully in the parent cell, which eventually disintegrates, releasing the new cells to the enviorment

A

Budding

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10
Q

In some Cyanobacteria, many nucleoids may accumulate in an enlarged round cell or along a filament, leading to the generation of many new cells at once. The new cells often split from the parent filament and float away in a process called

A

Fragmentation

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11
Q

Organisms that cannot make certain nutrients and require them to be added to the medium

A

Fastidious organisms

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12
Q

The _____ is the time between the same points of the life cycle in two successive generations
Only in eukaryotes

Also called the doubling time

A

Generation time

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13
Q

Generation time for tuberculosis

A

15 to 20 hours

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14
Q

Bacterial growth curve

A

Lag phrase
Log phase
Stationary phase
Death or decline phase

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15
Q

No increase in number of living cells

A

Lag phase

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16
Q

Exponential increase in number of living bacterial cells

A

Log phase

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17
Q

Plateau in number of living bacterial cells rate of cell division and death roughly equal

A

Stationary phase

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18
Q

Exponential decrease in number of living bacterial cells

A

Death phase

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19
Q

Are microorganisms, typically archea, that thrive in extremely hot environments, with optimal growth temperatures above 80 degrees

A

Hyperthermophiles

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20
Q

Are adapted to moderate temperatures, with optimal growth temperatures ranging from room temperature (20 degrees Celsius) to about 45 degrees Celsius.

Examples : humans, E. coli, salmonella, lactobacillus

A

Mesophiles

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21
Q

Prefer cooler temperatures, from a high temp of 25 degrees Celsius to refrigeration temps of about 4 degrees Celsius. Responsible for food spoilage in refrigerated foods

A

Psychrotrophs

22
Q

Require oxygen

A

Obligate aerobes

23
Q

Do not require oxygen and are killed by oxygen

Only grows in oxygen free environments

A

Obligate anaerobes

24
Q

A bio film forms when _____ bacteria of one or more species adhere to the surface, produce slime, and form a colony

A

Planktonic

25
Q

In biofilm formation _____ cells are present in the first and last step of biofilm formation

A

Planktonic

26
Q

Are organisms that can grow at 0 degrees and below and have an optimal growth temperatures close to 15 degrees Celsius

A

Psychrophiles

27
Q

Involve a stepwise dilution of a substance, to reduce its concentration gradually.

A

Serial dilution

28
Q

Refers to counting the cells in a liquid culture or colonies on a plate. It is a direct way of estimating how organisms are present in a sample.

A

Direct cell count

29
Q

Can be used to differentiate between viable and dead bacterial cells in a sample

A

Fluorescence staining

30
Q

Why must serial dilutions be made before doing a direct plate count ?

A

To reduce the concentration of bacteria, if the concentration is to high, the colonies on the plate will be to numerous to count (TNTC) leading to inaccurate results.

31
Q

What range of colonies is ideal for direct plate count ?

A

30-300 colonies

32
Q

The _____ involves mixing the diluted sample with molten agar, allowing colonies to grow both inside and on the surface of the agar. It’s suitable for aerobic and anaerobic organisms.

A

Pour plate method

33
Q

The ______ involves spreading the diluted sample on the surface of solidified agar, allowing colonies to grow on its surface. It only supports aerobic growth

A

Spread plate

34
Q

A statistical procedure for estimating of the number of viable microorganisms in a sample

Estimation of the number of coliforms in a sample of pond water

A

MPN most probable number

35
Q

Reflects bacterial growth because as bacteria multiply in a liquid culture, they scatter light, making the solution cloudy.

A

Turbidity

36
Q

The higher the ______, the more bacterial cells are present, indicating increased growth.

A

Turbidity

37
Q

The most common form of bacterial reproduction, where a single cell divides into two identical daughter cells of equal size

The parent cell splits into several smaller pieces, each of which can grow into a new organism

A small growth, forms on the parent cell, grows, and eventually detaches to become a new organism

A

Binary fission

Fragmentation

Budding

38
Q

A _____ is a complex community of microorganisms that adhere to surfaces and are embedded in a protective extracellular matrix

A

Biofilm

39
Q

Where do biofilms form ?

A

Any surface, including medical devices, teeth, natural environments, plaque, rocks, water, and tissues in the body

40
Q

Do biofilms only contain a single species

A

No, they contain multiple species of organisms including bacteria, fungi, and Protozoa

41
Q

What advantages do microbes in biofilm enjoy ?

A

Protection from environmental stresses, antibiotics, and the immune system, as well as enhanced nutrient availability

42
Q

Can contribute to chronic infections as the protective matrix makes microbes more resistant to antibiotics and immune responses.

A

Biofilms

43
Q

Obligate anaerobic bacteria must be grown under conditions devoid of oxygen. The most common approach is culture in an

They include chemical packs that remove oxygen and release carbon dioxide.

A

Anaerobic jar

44
Q

Each species has a range of temperatures in which it will grow.

The range is expressed as

A

Minimum - no growth below temperature

Optimal - most rapid growth

Maximum - no growth above this temp

45
Q

Human pathogens you typically belong to the _______ group. They thrive in moderate temps, typically between 20c and 45c which includes the human body.

A

Mesophiles

46
Q

Contains extracts or digests of plants, animals, or yeast.

Ex. Nutrient broth, tyrptic soy broth, brain heart infusion

A

Complex media

47
Q

Is prepared by measuring out each individual chemical components

A

Defined media

48
Q

_____Contains growth factors, vitamins, and other essential nutrients to promote the growth of______

A

Enriched media

Fastidious organisms

49
Q

Media that inhibit the growth of unwanted microorganisms and support the growth of the organism of interest by supplying nutrients and reducing competition are called

A

Selective media

50
Q

The _____ make it easy to distinguish colonies of different bacteria by a change in the color of the colonies or the color of the medium

A

Differential media

Microbiology (30 decks)

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