Mini Exam 4

Question 1

Requirements for growth

Answer 1

• temperature
• pH
• osmotic pressure
• elements; CNOPS
• amino acids and nucleotides (if not made)
• trace elements (zinc, iron, copper)
• growth factors (vitamins not made by microbe)

Question 2

Extremophiles

Answer 2

prefer extreme environments; have adapted to survive and grow

Question 3

Optimal temperature

Answer 3

Temperature with highest growth

Question 4

Psychrophile

Answer 4

Cold, even below freezing, ~ -10 to 20 C

Question 5

Psychrotroph

Answer 5

Low temps, ~0-30 C

Question 6

Mesophile

Answer 6

Moderate temps, ~10-50 C

Question 7

Thermophile

Answer 7

Hot temps, ~40-72 C

Question 8

Hyperthermophile

Answer 8

Very hot temps, even over boiling, ~65-110 C

Question 9

Refrigeration, danger zone

Answer 9

• Danger zone is where bacteria grow quickly, ~60-130 F or ~15-50 C
• refrigeration; may allow slow growth of SPOILAGE but few pathogens, container size impacts cooling time, ~0-5 C

Question 10

pH

Answer 10

Affects protein charge (function)
- acidophile likes 1-5.5
- neutrophils likes 5.5-8.5
- alkaliphile likes 7.5-11.5

Question 11

Osmotic pressure

Answer 11

Aka salinity; describes concentration of solutes in a solution, most bacteria prefer ISOTONIC (outside and inside same)

Question 12

Hypertonic solutions

Answer 12

Cause water to rush OUT of a cell; outside concentration > than inside of cell

Question 13

Plasmolysis

Answer 13

Shriveling of bacteria cytoplasm, happens in hypertonic solutions

Question 14

Halophile

Answer 14

likes high salt environments

Question 15

Acidophile

Answer 15

likes acidic environments

Question 16

Akaliphile

Answer 16

likes basic environments

Question 17

Element requirements

Answer 17

Carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur

Question 18

Decompostiion

Answer 18

Microbes get CHNOPS by decomposing dead organisms

Question 19

Carbon fixing

Answer 19

CO2 (inorganic) —> organic carbon by photoautotrophs or chemoautotrophs (oxidize inorganic molecules)

Question 20

Nitrogen fixation

Answer 20

N2 —> organic molecules

Question 21

Fixing

Answer 21

Microbes get CHNOPS by fixing fas forms from atmosphere

Question 22

ROS

Answer 22

reactive oxygen species; since it is very electronegative
- unpaired electron make these forms of oxygen dangerous
- ex: peroxide, superoxide anion

Question 23

SOD & Catalase

Answer 23

Enzymes that revert ROS species to H2O; allows organisms that use oxygen to survive
- SOD = superoxide dismutase; handles superoxide (WORST) to hydrogen peroxide (LESS damaging than superoxide) and oxygen molecules
- Catalase convert hydrogen peroxide to water and oxygen

Question 24

Aerobes

Answer 24

require oxygen during ATP production (respiration)

Question 25

Anaerobes

Answer 25

doesn’t need oxygen during ATP production (fermentation)

Question 26

Obligate

Answer 26

Aerobes: oxygen required; SOD/Catalase +/+ Anaerobes: cant grow with oxygen present; SOD/Catalase -/- Growth pattern will either be all at TOP (aerobes) or all at BOTTOM (anaerobes)

Question 27

Facultative and growth in media

Answer 27

Aerobes: both with or without oxygen, greater growth WITH oxygen; SOD/Catalase +/+ Growth pattern at top and throughout

Question 28

Agar

Answer 28

solid media; aka plates

Question 29

Broth

Answer 29

Liquid media; aka tubes

Question 30

Complex media

Answer 30

Made from yeast, meat, or plant extracts; aka RICH media

Question 31

Defined media

Answer 31

Made from individual chemical mixed together

Question 32

Enrichment culture

Answer 32

culture containing MIXTURE of microbes but which promotes growth of a SPECIFIC TYPE of microbe

Question 33

Selective and differential media

Answer 33

Selective: grows SPECIFIC microbes Differential: CHANGES in response to DIFFERENT kinds of microbial growth (usually color change)

Question 34

Binary fission

Answer 34

How bacteria divide, NOT mitosis bc no spindles/metaphase plate/gap phases (G1, G2) - FitZ protein constricts membrane to separate cells.

Question 35

Logarithmic growth (calculating # of cells)

Answer 35

each generation DOUBLES the # of cells

Question 36

Salmonella

Answer 36

- gram negative bacillus bacterium - facultative anaerobe (ATP w oxygen or fermentation w/o) - intracellular pathogen, gut epithelium - causes food borne illness; typhoid for some species - fecal to oral route Steps to infect 1. Adhesion 2. Secretion and membrane ruffling 3. Internalization and membrane recovery

Question 37

C.diff

Answer 37

- gram positive, motile (flagella) , obligate anaerobe - forms endospores (how it survives near oxygen) - emerging pathogen, common HAI and nursing homes - kept at bay by host microbiome (antibiotics harm this) - disrupt gut cytoskeleton by toxin A & B - causes gut inflammation (colitis) and diarrhea - fecal transplant treatment