Microbial Nutrition and Growth

Question 1

Which of the following culture methods must be done for an organism that cannot exist in the presence of oxygen?

Answer 1

Reducing media in an airtight jar

Question 2

Organisms that preferentially grow in the ice sheets of Antarctica are described as

Answer 2

psychrophiles

Question 3

Quorum sensing is

Answer 3

the ability to respond to changes in population density

Question 4

Why is optimal temperature important to maintain in regard to proteins?

Answer 4

It keeps proteins from denaturing.

Question 5

Microorganisms requiring a large number of growth factors for their optimal growth are referred as

Answer 5

Fastidious Organisms

Question 6

In a defined medium

Answer 6

the exact chemical composition of the medium is known

Question 7

Why is NADH an important growth factor for microorganisms?

Answer 7

It serves as an electron carrier in energy-producing pathways.

Question 8

What is the role of oxygen in aerobic metabolism?

Answer 8

It serves as a final electron acceptor in electron transport.

Question 9

For an organism to be pathogenic to humans it would likely need to be a

Answer 9

neutrophile

Question 10

An organism that uses CO2 and acquires energy from hydrogen would be classified as a

Answer 10

chemoautotroph

Question 11

Barophiles

Answer 11

cannot cause diseases in humans

Question 12

A media that can grow only certain types of microbes is best defined as

Answer 12

selective

Question 13

A microbe that can tolerate high salt concentration is known as a

Answer 13

facultative halophile

Question 14

In a microbiology laboratory, what does culturing mean?

Answer 14

Culturing is the act of growing microbes in a scientific setting.

Question 15

Colony (genetic material same)

Answer 15

An aggregation of cells arising from a single parent cell

Question 16

Biofilm (form interactions within organism)

Answer 16

Collection of microbes living on a surface in a complex community

Question 17

Nutrients necessary for growth

Answer 17

Carbon, oxygen, nitrogen, and hydrogen are necessary for cell growth and cell production)

Question 18

Organism based on used of carbon

Answer 18

Autotrophs and heterotrophs

Question 19

Organism based source of energy

Answer 19

Chemotrophs (anaerobic and aerobic respiration or fermentation will be on this one) and phototrophs

Question 20

Oxygen is essential for obligate aerobes

Answer 20

Oxygen is deadly for obligate anaerobes

Question 21

Aerobes

Answer 21

requires oxygen to survive must be able to handle the toxic fermentation of oxygen
Ex:Bacillus

Question 22

Anaerobes

Answer 22

Doesn’t require oxygen to survive
Ex: Clostridium sporogenes

Question 23

Facultative anaerobes

Answer 23

Prefer oxygen but they can survive without it
Ex: Escherichia Coli and Staphylococcus

Question 24

Aerotolerant Anaerobes

Answer 24

Do not have a preference for oxygen where there’s less competition is streptococci an streptococci pneumonia
Ex:Streptococcus pyogenes

Question 25

Microaerophiles

Answer 25

Requires low levels of oxygen even lower than the atmosphere

Question 26

Chemical and energy requirements for growth

Answer 26

-Nitrogen levels need to be 70 to 80% of the atmosphere made of nitrogen -Nitrogen fixation -Trace elements molecules needed -Growth factors (fastidious organisms really difficult to grow syphilis can growth on the human body unique organisms can't grow in any other medias) -Temperature - If too low, membranes become rigid and fragile. – If too high, membranes become too fluid. (Death of cell both can cause this) Thriving and Surviving is different

Question 27

Five categories of Microbes

Answer 27

-Psycholophiles can trive in the refrigerator can't survive human temperature like algae -Psycholtolerants can survive in the refrigerator and can survive the human body temperature -Mesophiles boil time becomes important -Thermophiles can trive in hot temperatures but wil not survive the human body -Hyperthernophiles organisms like archae that survive in really hot temerpatures

Question 28

Physical requirements from growth

Answer 28

-Neutrophiles the human neutral pH -Acidophikes vagina yeast infection candida albicans -Alkaliphiles cholera molds prefer sugar and acid organims -Baraphiles live under extreme pressure like organims that live under the ocean Osmotic pressure(limiting to kills them with water) -Hypotonic lower osmotic pressure which causes water to enter cell – Hypertonic higher osmotic pressure which causes water to leave the cell -Hydrostatic pressure organism that can survive the pressure from the ocean

Question 29

Synergistic relationships

Answer 29

cooperative relationships both of the organisms are going to benefit but relationships are required to survive Ex: Biofilms organisms will benefit when attached to biofilms ocean rocks green stuff. Complex relationships among numerous microorganism and many organisms are more harmful as a part of a biofilm

Question 30

Symbiotic relationships

Answer 30

Need a relationship to survive

Question 31

Quorum sensing

Answer 31

Increase has density of the environment increases

Question 32

Insolation techniques to obtain CFU a coloning forming unit

Answer 32

-Streak plates culture will grow only in the media -Pour plates culture will grow through the media

Question 33

Complex Media

Answer 33

Nutrients commonly derived from breakdown of yeast, beef ,soy and proteins

Question 34

Selective media

Answer 34

Contain substances that favor or inhibit growth of particular microorganisms Ex: Fungi thrives in acidic environments with acidophilus

Question 35

Differential media

Answer 35

Different bacteria growing on the media are distinguished by Presence of visible changes in the medium like from red to yellow Differences in the appearance of colonies Blood Agar hemolysis is not selective anything can grow in different media physical changes will appear different in colors from yellow to red when bacteria grow

Question 36

A typical growth curve number of live cells and time

Answer 36

at the starting there's 1. Lag phase 2. Log phase 3. Stationary phase 4.Death decline phase

Question 37

Direct Methods not requiring incubation

Answer 37

Coulter counter -counts cells as they interrupts an electrical current Flow cytometry -detects changes in light transmission as cells pass a detector Microscopic counts

Question 38

Direct methods requiring incubation

Answer 38

Serial dilution and viable plate counts Membrane filtration Estimating the number of microorganisms is useful * Determine severity of certain infections * Determine effectiveness of food preservation techniques * Measure the degree of contamination of water supplies Evaluate disinfectants and antibiotics

Question 39

Indirect methods

Answer 39

Turbidity Often the more turbid a culture, the greater the bacterial population -Measuring Microbial Growth -Metabolic activity -Dry weight -Molecular methods -Isolate D N A sequences of unculturable prokaryotes