Bacterial Growth

Question 1

growth characteristics may determine disease site example

Answer 1

bacteria requiring oxygen unlikely to be found in enteric tract

Question 2

bacteria are identified by _

Answer 2

their metabolic characteristics

Question 3

What is the first step in examining and identifying bacteria?

Answer 3

isolating and growing them in the lab in pure culture

Question 4

complex media

Answer 4

contains uncharacterized mixtures of compounds; used for routine growth

Question 5

defined media

Answer 5

contains specific chemical mixture; used for nutritional study and requires knowledge of bacterial growth requirements

Question 6

liquid media

Answer 6

used for growing larger amounts of bacteria

Question 7

solid media

Answer 7

used for isolating and purifying cultures, estimating viability, temporary storage, and other purposes

Question 8

agar

Answer 8

will turn liquid media to solid media

Question 9

enriched selective media

Answer 9

supports growth of most organisms without fastidious growth requirements

Question 10

examples of enriched selective media

Answer 10

blood agar, chocolate agar, mueller-hinton agar, thioglycolate broth, sabouraud dextrose agar

Question 11

blood agar

Answer 11

recovery of bacteria and fungi

Question 12

chocolate agar

Answer 12

recovery of bacteria; haemophilus and neisseria

Question 13

mueller-hinton agar

Answer 13

bacterial susceptibility testing

Question 14

thioglycolate broth

Answer 14

enrichment broth for anaerobic bacteria

Question 15

sabouraud dextrose agar

Answer 15

recovery of fungi

Question 16

selective media

Answer 16

designed for recovery of specific organisms that may be present in mixture; supplemented with inhibitors that suppress growth of unwanted organisms

Question 17

examples of selective media

Answer 17

macconkey agar, mannitol salt agar, xylose lysine deoxycholate agar, middlebrook agar, CHROMagar

Question 18

macconkey agar (selective)

Answer 18

gram-neg

Question 19

macconkey (differential)

Answer 19

lactose-fermenting species

Question 20

mannitol salt agar (selective)

Answer 20

staphylococci

Question 21

mannitol salt agar (differential)

Answer 21

S. aureus

Question 22

xylose lysine deoxycholate agar (selective)

Answer 22

salmonella and shigella

Question 23

xylose lysine deoxycholate agar (differential)

Answer 23

salmonella and shigella

Question 24

middlebrook agar (selective)

Answer 24

mycobacteria

Question 25

CHROMagar

Answer 25

differential and selective for yeast

Question 26

differential media

Answer 26

selective media can be made differential by adding specific ingredients that allow identification of an organism

Question 27

specialized media

Answer 27

created for detection of specific organisms that may be fastidious or typically present in large mixtures of organisms

Question 28

examples of specialized media

Answer 28

buffered charcoal yeast agar (BCYE), lim broth, macconkey sorbitol agar, regan lowe agar

Question 29

BCYE agar

Answer 29

recovery of legionella and nocardia

Question 30

lim broth

Answer 30

recovery of streptococcus agalactiae

Question 31

macconkey sorbitol agar

Answer 31

recover of E. coli

Question 32

regan lowe agar

Answer 32

recovery of bordetella

Question 33

differentiation/identification in culture is based largely on _

Answer 33

sugar/amino acid metabolism

Question 34

hemolysis reaction on blood agar

Answer 34

hemolysis is a key characteristic to help distinguish among various streptococci/enterococci and staphylococci types

Question 35

alpha-hemolysis

Answer 35

greening of agar effect of H2O2 or pneumolysin; S. pneumoniae and most "viridans" strep

Question 36

beta-hemolysis

Answer 36

complete RBC lysis; exotoxins, GAS (S. pyogenes), GBS (S. agalactiae), and S. aureus

Question 37

gamma-hemolysis

Answer 37

no hemolysis; most enterococci or other staph

Question 38

bacterial growth curve

Answer 38

lag phase --> exponential growth --> stationary phase --> death phase

Question 39

phases of bacterial growth reflect _

Answer 39

populations of cells

Question 40

batch culture

Answer 40

closed system with finite resources; how to generate bacterial growth cruve

Question 41

lag phase

Answer 41

cells at the end of their previous culture history were depleted of metabolites and enzymes; now adapting to new environment

Question 42

exponential phase

Answer 42

new cell material is being synthesized at constant rate; new biomass increases in exponential manner

Question 43

how long does exponential phase last?

Answer 43

until nutrients are exhausted or toxic metabolites accumulate

Question 44

limiting factor for aerobic organisms

Answer 44

oxygen

Question 45

stationary phase

Answer 45

equilibrium between dying and new cells

Question 46

preferred pathogenic temp

Answer 46

37C

Question 47

preferred pathogenic pH

Answer 47

6-8

Question 48

obligate aerobes example

Answer 48

mycobacterium and pseudomonas

Question 49

microaerophiles examples

Answer 49

C. jejuni and H. pylori

Question 50

facultative anaerobes examples

Answer 50

E. coli and most clinically relevant bacteria

Question 51

obligate anaerobes examples

Answer 51

C. perfringens

Question 52

prokaryotic glycolytic pathways

Answer 52

embden-meyerhof-parnas (EMP), heterolactic pathway, and entner-doudoroff pathway (ED)

Question 53

EMP glycolysis

Answer 53

most common; net yield of 2 ATP and 2 NADH

Question 54

ED pathway

Answer 54

1 ATP/glucose

Question 55

catabolic fates of pyruvate

Answer 55

alcohol fermentation in yeast, carbon dioxide and water under aerobic conditions, and fermentation to lactate

Question 56

respiration

Answer 56

metabolism in which energy is derived from complete oxidation of a substrate by an outside electron acceptor

Question 57

What is needed for respiration?

Answer 57

glycolysis, TCA cycle, membrane with ETS, outside electron acceptor, ATPase enzyme

Question 58

_ ATPs per FADH2

Answer 58

2

Question 59

_ ATPs per NADH

Answer 59

3

Question 60

anaerobic respiration

Answer 60

uses a compound other than O2 as final electron acceptor

Question 61

fermentation

Answer 61

metabolism in which energy is derived from partial oxidation of an organic compound; no ATP generation

Question 62

fermentation does not use _

Answer 62

outside electron acceptors or ETS

Question 63

lactobacillus fermentation

Answer 63

lactate

Question 64

propionibacter fermentation

Answer 64

propionate

Question 65

shigella fermentation

Answer 65

formate

Question 66

escherichia fermentation

Answer 66

H2

Question 67

clostridium fermentation

Answer 67

isopropanol and butanol