Bi 311 Lab Cards

Front 1

Exercise 19:

What does the cultivation of microorganisms on an artificial growth medium require?

Back 1

Requires that the medium supply anll the nutritional and energy requirements necessary for growth.

Front 2

Exercise 19:

What is a complex medium?

Back 2

A medium using rich extracts of meat or plants that would supply all the amino acids, nucleotide bases, vitamins and other growth factors; most medium is complex.

Front 3

Exercise 19:

Why is it referred to as complex?

Back 3

Because the exact composition and amounts of the individual amino acids, vitamins, growth factors and other components that make up the medium are not exactly known.

Front 4

Exercise 19:

What is a defined medium?

Back 4

A medium where the specific chemical components are known and the individual components are weighed out exactly to make the medium.

Front 5

Exercise 19:

What are the basic nutritional requirements of bateria?

Back 5

carbon source, energy source, nitrogen, minerals, vitamins and growth factors, and water.

Front 6

Exercise 19: carbon source
-Organisms can be divided into 2 groups based on their carbon requirements, what is one of the groups?

Back 6

Heterotrophs: get carbon from organic compounds like polysac, carbs, a.a, peptides & protein; meat and plants extracts must be added to complex media to supply these nutrients.

Front 7

Exercise 19: carbon source
-Besides heterotrophs, name the other group of organisms:

Back 7

Autotrophs: get carbon by fixing carbon dioxide; must sythesize all complex molecules that make the bacterial cell.

Front 8

Exercise 19: energy source

-Define chemotroph

Back 8

Organisms that get their energy from the breakdown of organic molecules by fermentation or respiration; most bacteria belong to this group.

Front 9

Exercise 19: energy source

-Define Chemolithotrophs

Back 9

Organisms that oxidize inorganic ions such as nitrate or iron to obtain energy; include nitrifying and and iron bacteria.

Front 10

Exercise 19: energy source

-Define Photoautotrophs

Back 10

Organisms that contain photosynthetic pigments such as chlorophyll or bacteriochlorophyll that convert solar energy into chemical energy via photosyn.; no energy source in medium except light; eg. cyano, green and sulfur bacteria.

Front 11

Exercise 19: energy source

-Define Photoheterotrophs

Back 11

Organisms that get their energy from photosynthesis, but their carbon from growth on organic molecules like succinate or glutamate; not many bacteria but some purple nonsulfur.

Front 12

Exercise 19: energy source

-What's the difference b/w photoautotrophs and photoheterotrophs?

Back 12

-Photoautotrophs use their energy to fix CO2, for their carbon, while photoheterotrophs get their carbon needs from organic molecules.

Front 13

Exercise 19: nitrogen
-How do bacteria get their N?

Back 13

Some synthesize it, some gain it via organic molecules, others can fix atmospheric N like the bacteria Rhizobium and Azotobacter.

Front 14

Exercise 19: Minerals

-Why are they so important for bacteria>

Back 14

B/c metals are req. in bacterial metabolism as they are cofactors in enzymatic reactions and are integral parts of molecules like cytochromes;

Front 15

Exercise 19: Minerals

-What metals are required for growth?

Back 15

Sodium, potassium, calcium, magnesium, maganese, iron, zinc, copper, cobalt and phosphorous.

Front 16

Exercise 19: Vitamins & Growth Factors
-What do you need to add to the medium for these?

Back 16

Blood and serum.

Front 17

Exercise 19: Vitamins & growth Factors

-What do vitamins do for the bacteria?

Back 17

Serve as coenymes, eg. the vit niacin is part of the coenzyme NAD; some bacteria req vits b/c they can't synthesize them, others can, but its nec. to add growth factors for AMPLE growth of certain bacteria, like pathogens.

Front 18

Exercise 19: Water

-why do cells require an aqueous environment?

Back 18

Cells consist 70-80% of water; need aq. environ. b/c enzymatic reactions and transport only occur in the presence of water; (h20 also maintains copmonents in the cytoplasma)

Front 19

Exercise 19: Water

-Why do we need to use distilled water when preparing medias?

Back 19

B/C tap water can contain minerals like calcium that could react with the peptones and meat extracts to cause unwanted precipitates and cloudiness.

Front 20

Exercise 19:

-What id a selective medium?

Back 20

Media made with components (like antibiotics, dyes) that will allow certain bacteria to grow but will inhibit others from growing

Front 21

Exercise 19:

-What is differential medium?

Back 21

Contains substances that cause some bacteria to take on an appearance that distinguishes them from other bacteria, eg: Staphylococcus aureus

Front 22

Exercise 19:

-What is agar?

Back 22

A complex polysaccharide from sea weed, added to liquid media to solidify it; first used in Koch's lab; melts at 100*C and solidifies at 45*C (temp that bacteria can be innoculated @ w/o killing cells

Front 23

Exercise 19:

-what do you add to media if the pH is too high?

Back 23

HCL

Front 24

Exercise 19:

-what do you add to media if the pH is too low?

Back 24

NaOh

Front 25

Exercise 19:

-When filling the test tubes with agar, what do you need to make sure you do to maintain the agar in solution?

Back 25

Keep the medium on a stirring hot plate, usually a magnetic stirrer is used.

Front 26

Exercise 19:

-When medium is to be used for fermentation, what do you need to add to the test tube?

Back 26

You need to add a Durham tube, open end down, BEFORE adding the medium.

Front 27

Exercise 19:

-Why do we use an autoclave for sterilization?

Back 27

B/C it can achieve the complete sterilization temperature of 250*C, by developing 15lbs/square inch of steam.

Front 28

Exercise 21:

-How are bacteria classified?

Back 28

Based on their requirement for air that contains 20% oxygen.

Front 29

Exercise 21:

-What are Obligate Strict Aerobes?

Back 29

Organisms that require oxygen for growth - primarily carry out respiratory metabolism where oxygen acts as a terminal electron acceptor.

Front 30

Exercise 21:

-What are Obligate Strict Anaerobes

Back 30

Bacteria that can't tolerate oxygen; carry out fermentation aka anaerobic respiration for growth; sensitivity is to the by products of oxygen like peroxide.

Front 31

Exercise 21:

-what is the diff b/w aerobes and anaerobes?

Back 31

Aerobic bacteria have enzyme systems that convert O2 by products so that they don't destroy their cells, anaerobes lack these enzymnes.

Front 32

Exercise 21:

-what is a facultative anaerobe?

Back 32

bacteria that can grow by respiratory means if O2 is present, if there's no )2 can grow via fermentation, eg. E.coli

Front 33

Exercise 21:

-what are microaerophiles?

Back 33

organisms that require O2 on amounts lower that the atmosphere; growth can be done in a candle jar

Front 34

Exercise 21:

-what are aerotolerant bacteria?

Back 34

Bacteria that can grow in O2, but that don't use it as terminal electron acceptor, hence they are indifferent to the presence of O2; carry out fermentation; grow better with little O2, eg. Streptococcus

Front 35

Exercise 21:

-What's a TGYA shake?

Back 35

A solid medium used to prepare shake tubes to det the O2 req of diff. bacteria

Front 36

Exercise 21:

-What's FTM?

Back 36

Fluid thioglycollate medium is a rich liquid medium that supports the browth of aerobic and anaerobic bacteria; conatins resazurin dye that turns pink when there's O2.

Front 37

Exercise 21:

-What is Brewer's Anaerobic agar?

Back 37

A solid medium used for culturing anaerobic bacteria in petri dishes, contains thioglycollate, a reducer and resazuirn O/R reducer

Front 38

Exercise 21:

-How do you incubate anaerboic bacteria in an O2 free environment?

Back 38

In FasPak anaerobic jars, where hydrogen is generated to remove the oxygen by forming water; palladium pellets catalyze the reaction at room temperature; indicator strip of methblue used, will be colorless if no O2.