Microbial Growth

Question 1

What sources do microorganisms need to grow?

Answer 1

carbon and energy

Question 2

Increase in both cell mass and cell numbers.

Answer 2

growth

Question 3

Microbes have different nutritional needs based on their (blank).

Answer 3

ecological niches

Question 4

What must be supplied from the environment?

Answer 4

essential nutrients

Question 5

What are macronutrients?

Answer 5

major elements in cell macromolecules, also cations necessary for protein function

Question 6

What are micronutrients?

Answer 6

trace elements necessary for enzyme function

Question 7

(blank) fix CO2 and assemble into (blank).

Answer 7

autotrophs, organic molecules

Question 8

What do heterotrophs use?

Answer 8

preformed organic molecules

Question 9

All organisms require a (blank).

Answer 9

energy source

Question 10

Phototrophs:

Answer 10

obtain energy from light

Question 11

Chemotrophs:

Answer 11

obtain energy from oxidation-reduction

Question 12

Lithotrophs:

Answer 12

use inorganic molecules

Question 13

Organotrophs:

Answer 13

use organic molecules

Question 14

What percent of earth’s atmosphere is nitrogen?

Answer 14

79%

Question 15

What plays a key role in the nitrogen cycle?

Answer 15

bacteria

Question 16

Possess nitrogenase enzyme which converts N2 to NH4+.

Answer 16

nitrogen fixers

Question 17

List the things to consider when trying to culture an organism.

Answer 17

1) how the cell generates energy
2) the form of carbon utilized
3) the form of nitrogen used

Question 18

Less than (blank) of bacteria are culturable.

Answer 18

1%

Question 19

How are bacteria grown?

Answer 19

separately in pure complexes

Question 20

We try to measure growth under optimal (blank) and (blank) conditions.

Answer 20

nutritional, environmental

Question 21

Complex/Rich Media: (type of bacteria culture)

Answer 21

nutrient rich, exact chemical composition is poorly defined

Question 22

Minimal Defined Media: (type of bacteria culture)

Answer 22

contain only nutrients essential for growth

Question 23

Enriched Media: (type of bacteria culture)

Answer 23

complex media to which specific growth factors or organic components are added

Question 24

Selective Media: (type of bacteria culture)

Answer 24

favour the growth of 1 organism over another

Question 25

Differential Media: (type of bacteria culture)

Answer 25

exploit differences between 2 species that grow equally well

Question 26

How do most microbes grow?

Answer 26

bacteria in most soil and water ecosystems are oligotrophs

Question 27

What is an oligotroph?

Answer 27

have optimal rate of growth in low nutrient conditions

Question 28

What are the 2 main forms of culture media?

Answer 28

liquid/broth and solid

Question 29

Explain liquid/broth culture media.

Answer 29

cells are in suspension, used for obtaining large number of cells or secreted products (pure culture)

Question 30

Explain solid culture media.

Answer 30

usually gelled with agar, grow in colonies, used to try an separate bacteria, study diversity and isolate pure cultures

Question 31

How are pure cultures isolated?

Answer 31

dilution streaking and spread plating

Question 32

What is the benefit of dilution streaking?

Answer 32

it increases probability of obtaining a single bacterium

Question 33

What is the benefit of spread plating?

Answer 33

nicely separated colonies

Question 34

Time it takes for a population to double.

Answer 34

generation time

Question 35

bacteria divide at a constant interval true or false?

Answer 35

true

Question 36

Fastest generation?

Answer 36

clostridium perfrigens

Question 37

Slowest generation?

Answer 37

mycobacterium leprae

Question 38

What is a batch culture?

Answer 38

volume of liquid media with a closed system

Question 39

Why is a batch culture useful?

Answer 39

it is the simplest way to model the effects of a changing environment

Question 40

Why is this true?

Answer 40

changing conditions in this system greatly affect bacterial physiology and growth

Question 41

It illustrates ability of bacteria to adapt true or false?

Answer 41

true