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Microbio > Chapter 6 (EXAM 2) > Flashcards

Chapter 6 (EXAM 2) Flashcards

1
Q

Viable count

A

The number of microorganisms in a particular media that are alive

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2
Q

Total count

A

The number of microorganisms in a media that are both living and dead`

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3
Q

Generation time

A

The time for a cell to divide and population to double; species specific
The rate is always constant \

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4
Q

What is the growth curve and its phases

A

The curve of microorganisms in unnatural environment, not soil or water
Phases are lag, log, stationary and death

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5
Q

Lag phase

A

Little to no division of growth in bacteria
Turn genes on that were silences
Once they’ve gotten enough food they move to next phase

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6
Q

Log phase

A

Exponential increase in population

Industrial producers will create a condition of hemostatic environment(constant)

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7
Q

Stationary phase

A

When resources become scarce, the number of dying cells dont equal the number of cells dividing
At the end you see less growth, organisms are smaller then normal

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8
Q

Death phase

A

Organisms planning for death of population and produce endospores if the bacteria is able to

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9
Q

What phases are exponential

A

Log and death

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10
Q

What are plasmids

A

What bacteria pick up at later stationary phase and beginning of death phase in desperation to survive.
Tiny circles of genetic material that contain genes of resistance

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11
Q

What are growth influences of cells

A

Cells require water bc it aids in diffusion of materials
Like less then 1% salt, about .85 NacI
Applies to most bacteria except staph and hydrophilic archer bacteria can tolerate higher salt solutions

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12
Q

what does it mean to be phacotactive

A

Be on a needs basis with or without salt

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13
Q

Isotonic

A

Same on the outside as it is on the inside

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14
Q

Hypertonic

A

Enviroment is more concentrated in solutes on the outside

Water goes out cell then what’s inside the cell

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15
Q

Hypotonic

A

Solution cell is in is more watery compared to what’s inside of the cell. Cells take more water in

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16
Q

Describe psychrophiles

A

Cold organisms that can live btwn -10 & 20

15 being optimum temp

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17
Q

Describe psychrotrophs

A

Cold loving organism that can go in fridge range in 0-30

25 being optimum temp

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18
Q

Describe mesophils

A

Live within 10-50 range

37 being their fav temp ( body temp)

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19
Q

Describe thermophils

A

Like warm temp. Live in compost piles, dump, heat resistance
Live in 40-72 range, 62 being their fav temp

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20
Q

Describe hyperthermophils

A

Type of archer, extreme bacteria

Like temperature of 67-110, 94 being fav temp

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21
Q

Media: broth

A

Test tubes filled with liquid

22
Q

media: slant

A

Test tubes with agar at an angle, cuts down contamination

23
Q

media: deep

A

Test tube with media that goes straight across. You use a needle to push bacteria down under the surface to activate anaerobic enzymes

24
Q

media: buffer

A

Added to medias to counteract the effect of acids

25
Q

synthetic media

A

made of pure chemicals

26
Q

complex media

A

contain foods, peptones

27
Q

What is Agar

A

Polysaccharide from algae, jelly

Used in media to mountain moisture to prevent dehydrating and freezing at certain temps

28
Q

selective media

A

Allows the growth of 1 microorganism over the other

Examples are EMB, Pea agar and Maconkey

29
Q

What is an EMB

A

selective media, that allows gram - to grow over gram+

30
Q

What is a PEA agar

A

Comes with or without blood, selective for gram +

31
Q

Why is counting microbes important

A

It helps determine how bad food is or how intense an infection may be
Ways to count include direct: streak plate, pour plate, spread plate, serial dilutions, filtration, MPN, chambers and culture counter
indirect: spectrophotometer, metabolic

32
Q

What are colonies

A

Time mounds of bacteria that contain 100’s of bacteria that create a colony. Have special characteristics
Plate has to be streaked tp create the colonies

33
Q

What is a streak plate

A

When small amount of bacteria is placed on a plate
Create 4 quadrants but bacteria is only aseptically applied once.
IT is not a direct count, more of a ball park guess of number of colonies

34
Q

What is the pour plate method

A

Bacterial dilution 1.0-0.1 ml
The disadvantage of this is that bacteria can be destroyed and appear different under than they do above. Hard to identify
1. inoculate an empty plate
2. Add melted agar
3. Swirl to mix
4. Colonies grow underneath(facultative anaerobe) or onto of the agar

35
Q

What is the spread plate method

A

Same as the put plate method except you spread out the organisms on the surface with beads and colonies grow only on the surface

36
Q

What are serial dilutions

A

Goal is 30-300 colonies on a plate, to do this dilutions need to be done
1:100= 1 ml added to the 9 ml of broth
The number of colonies will get lower the more the inoculum is diluted but easier to count bacteria in those

37
Q

What is filtration

A

When filters are placed to trap bacteria flowingg in air or water
The filters that trap bacteria are placed on Petri dish to get food to grow, they are then counted and identified

38
Q

What is MPN

A

Method that fives you a very wide range of possible number of microbes that can grow in combinations of test tubes containing nutrient agar
10ml= 5 bacteria
1 ml= 3 bacteria
0.1= 1 bacteria
Gives us a number of positive tubes and most possible number of bacteria
Not done often

39
Q

What is the petfroff houser chambers

A

A specified volume under a coverslip on top is a grid to count the number of bacteria
The disadvantage is that it counts living and dead bacteria, and any bacteria with tails can swim underneath the surface and not be counted

40
Q

What is the Coulter counter

A

Is used if you don’t want to plate out bacteria
Fluids can pass through and instruments are used to count the number of bacteria. Is useful in research labs and hospitals when you want to know immediately the bacteria count
Disadvantage is that other particles that aren’t bacteria can be counted aswell

41
Q

What is a spectrophotometer

A

Indirect count
Measures the % of light that passes through a solution and tells you the approximate amount of particles that may be in the solution
It is important to dry and weigh so you can get an accurate number when it come to fungi bc they are masses of fibrous particles

42
Q

What is metabolic counting

A

indirect count
Where you measure inout and output. You can take a guess of how many microbe may be there if you know how much food you fed and what kind of organisms it may be
Can also count carbon dioxide and acids

43
Q

How do salts and sugars preserve food

A

They create a hypertonic enviroment

44
Q

What is facultative anaerobe on a graph

A

Has a with and without line, v shape facing north east

45
Q

In the bacterial growth curve, which phases are logarithmic

A

Log and death phase

46
Q

Most bacteria grow In what ph

A

7, neutral

47
Q

What is the generation time in bacteria

A

The time it takes for a cell to divide

48
Q

What phase are antibiotics effective

A

Log phase

49
Q

3 cells and ended with 192 cells, how many generations

A

6

50
Q

What do you call an organism that can live with or without salt

A

facultative halophile

51
Q

What do you call an organism killed by oxygen

A

obligate anaerobe

Microbio (16 decks)

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