Cultivation of Bacteria

Question 1

what effects bacterial growth?

Answer 1

nutritional factors
environmental factors

Question 2

what are abiotic environmental factors that affect bacterial growth?

Answer 2

temperature, pH, oxygen, CO, water availability/osmotic pressure

Question 3

what are most bacteria - pick on the chart

Answer 3

mesophiles

Question 4

what is the transport media and cultures media usual pH? why is this important

Answer 4

7 - has buffers to keep at this value
optimal pH for most bacteria 6.5-7.5

Question 5

label the aerobic capacity of the bacteria? ex. obligate aerobe, obligate anerobe

Answer 5

Question 6

what do anerobic bacteria require to grow?

Answer 6

anaerobic transport media
reducing culture media
anaerobic jar

Question 7

what is a capnophile?

Answer 7

bacteria requiring 5-10% CO2 for optimal growth

Question 8

what are most capnopiles aerobic descriptor?

Answer 8

microerophilic

Question 9

what type of bacteria do not require NaCl but can grow under saline?

Answer 9

Halotolerant bacteria

Question 10

how does transport media help prevent desiccation?

Answer 10

provide moisture until sample can be cultured

Question 11

what is a chemoheterotroph?

Answer 11

use organic compounds for energy and carbon

Question 12

what is a fastidious bacteria?

Answer 12

requiring additional organic compounds in their culture media

Question 13

Are most bacteria chemoheterotrophic or fastidious?

Answer 13

chemoheterotrophic

Question 14

which require more growth factors - chemoheterotrophic or fastidious?

Answer 14

fastidious

Question 15

match the term to the description - liquid media, solid media, semi-solid agars

1. used for isolation of pure cultures, estimating the number of viable bacteria
2. ideal for growing large numbers of bacteria
3. used for determining motility, growing microaerophiles

Answer 15

1 - solid media
2 - liquid media
3 - semi-solid agars

Question 16

what are growth factors

Answer 16

things that bacteria need for growth and the organism cannot synthesize

Question 17

Is agar a solidifying agent or nutrient?

Answer 17

solidifying agent

Question 18

what is a colony?

Answer 18

population of cells arising from a single cell or spore, or from a group of cells of the same species or strain

Question 19

what is the function of basal media?

Answer 19

sustain growth of less fastidious bacteria

Question 20

what is the function of enriched media?

Answer 20

basal media + additional nutrients, used to cultivate fastidious organisms

Question 21

what is the function of selective media?

Answer 21

reagents added that inhibit the growth of unwanted bacteria while allowing the growth of others

Question 22

what is the function of differential (indicator) media?

Answer 22

contain components that allow the differentiation of closely related taxa based on appearance of colony or surrounding media

Question 23

what is the function of transport media?

Answer 23

for transport of clinical specimens to the lab, preserve microbial viability and help maintain the original ratio of microbes in the sample

Question 24

what is a pure culture?

Answer 24

contains only 1 species of microbe

Question 25

what are the goals of a preserved pure culture?

Answer 25

viability, purity, and genetic stability

Question 26

how can you preserve bacterial cultures?

Answer 26

subculture of growing cells, snap-freeze cells in broth w/ cryopreservative, freeze-dry cells suspended in lyophilization media

Question 27

how do bacteria grow? (mitosis, meiosis, binary fission, etc.)

Answer 27

binary fission

Question 28

what is generation time?

Answer 28

time required for population to double

Question 29

Label the growth phases

Answer 29

Question 30

describe lag phase

Answer 30

no cell division, preparing for growth

Question 31

describe log (exponential) phase

Answer 31

exponential growth

Question 32

describe stationary phase

Answer 32

zero population growth

Question 33

describe death/decline phase

Answer 33

exponential death

Question 34

After decline phase what can some viable bacteria enter?

Answer 34

long-term stationary phase

Question 35

define colony

Answer 35

population arising from a single cell or spore, or from a group of cells of the same species or strain

Question 36

what is the difference between a batch culture and continuous culture?

Answer 36

batch culture - grow in closed system, exponential growth cannot be maintained continuous culture - growth in chemostat, fresh medium continuously added, exponential growth can be maintained