chapter 6: microbial growth and nutrition

Question 1

How do microbes grow?

Answer 1

they grow in population not size

Question 2

colony

Answer 2

aggregation of cells arising from CFU

Question 3

CFU

Answer 3

colony forming unit

Question 4

What do cells require for metabolism?

Answer 4

a carbon source, a source of energy, and a source of electrons and hydrogen

Question 5

autotrophs

Answer 5

use inorganic sources as the sole source of carbon, make organic compounds from CO2

Question 6

heterotrophs

Answer 6

catabolize reduced organic molecules that they acquire from other organisms

Question 7

photons

Answer 7

contain lots of energy

Question 8

phototrophs

Answer 8

use light as an energy source

Question 9

chemotrophs

Answer 9

acquire energy from redox reactions

Question 10

redox reactions

Answer 10

reduction and oxidation

Question 11

nitrification

Answer 11

fixes atmospheric nitrogen

Question 12

What is the common element in all cells?

Answer 12

hydrogen

Question 13

organotrophs

Answer 13

acquire electrons from organic molecules

Question 14

lithotrophs

Answer 14

acquire electrons and hydrogen from inorganic sources

Question 15

obligate aerobes

Answer 15

need oxygen to live

Question 16

clostridium tetani

Answer 16

anaerobe that produces tetanus

Question 17

clostridium botilinum

Answer 17

botox

Question 18

What are the 4 types of toxic oxygen?

Answer 18

singlet oxygen, superoxide radical, peroxide anion, and hydroxyl radical

Question 19

carotenoids

Answer 19

pigments in phototropic microorganisms that prevents toxicity by removing excess energy from singlet oxygen

Question 20

superoxide radicals

Answer 20

very reactive and toxic to aerobes that must use superoxide dismutase enzymes to detox them

Question 21

Why are anaerobes sensitive to oxygen?

Answer 21

they lack superoxide dismutase

Question 22

Which type of toxic oxygen is a very reactive oxidizing agent?

Answer 22

singlet oxygen

Question 23

facultative anaerobes

Answer 23

-Aerobes that can maintain life by fermentation or anaerobic respiration
- Have a reduced metabolic efficiency

Question 24

aerotolerant anaerobes

Answer 24

Dont use aerobic metabolism but can tolerate oxygen because of detoxifying enzymes

Question 25

microaerophiles

Answer 25

Require oxygen in levels from 2%-10% It can be damaged at higher oxygen levels

Question 26

All the bacteria in a test tube are gathered at the top. What organism is this?

Answer 26

obligate aerobes

Question 27

All the bacteria in a test tube is gathered at the bottom. What organism is this?

Answer 27

obligate anerobes

Question 28

All the bacteria in a test tube are mostly at the top. What organism is this?

Answer 28

facultative anaerobes

Question 29

All the bacteria are dispersed throughout. What organism is this?

Answer 29

aerotolerant anaerobes

Question 30

nitrogen

Answer 30

often the growth limiting nutrient for many organisms

Question 31

nitrogen fixation

Answer 31

reduction of nitrogen gas to ammonia and an essential process for life on earth

Question 32

trace elements

Answer 32

other elements required in small amounts

Question 33

growth factors

Answer 33

organic chemicals that most organisms cannot synthesize

Question 34

ruminants

Answer 34

animals with rumen, a stomach sac with microflora

Question 35

microflora

Answer 35

helps to digest cellulose

Question 36

What are the 4 cow stomachs?

Answer 36

rumen, reticulum, omasum, abomasum

Question 37

What happens to proteins at high temps?

Answer 37

they denature and hydrogen bonds break

Question 38

minimum growth temp

Answer 38

lowest temp an organism can conduct metabolism

Question 39

maximum growth temp

Answer 39

the highest temp at which an organism can metabolize

Question 40

optimum growth temp

Answer 40

the temp at which an organisms metabolic activity is at the highest

Question 41

physchrophiles

Answer 41

0-20

Question 42

mesophiles

Answer 42

37 C

Question 43

thermophiles

Answer 43

70 C

Question 44

hyperthermophiles

Answer 44

120 C

Question 45

neutrophiles

Answer 45

live in pH range of 6.5-7.5

Question 46

acidophiles

Answer 46

grow best in acidic habitats

Question 47

alkalinophiles

Answer 47

live in alkaline soils and water

Question 48

antagonistic relationships

Answer 48

one organisms harms or kills the other

Question 49

synergistic relationships

Answer 49

each member receives a benefit that exceeds that of what they'd have on their own

Question 50

symbiotic relationships

Answer 50

organisms that live in contact so well that they depend on one another and rarely live outside the relationship

Question 51

biofilm

Answer 51

complex community of bacteria living together

Question 52

What are the benefits of the polymeric matrix of biofilm?

Answer 52

it can sequester substances in the film and protect the biofilm from antimicrobial drugs or the host's immune response

Question 53

qurom sensing

Answer 53

bacteria responds to the density of nearby bacteria and molecules to communicate with other bacteria

Question 54

What happens if biofilms communicate?

Answer 54

it can cause cystic fibrosis, kidney infections

Question 55

binary fission

Answer 55

cell grows to twice its size and divides in half to produce two daughter cells of equal size

Question 56

generation time

Answer 56

the time required for a bacterial cell to grow and divide

Question 57

arithmetic growth

Answer 57

simple addition,

Question 58

exponential growth

Answer 58

2n

Question 59

lag phase

Answer 59

cells adjust to their environment and prepare to divide

Question 60

log phase

Answer 60

rapid reproduction once necessary chemicals have been synthesized

Question 61

stationary phase

Answer 61

nutrients are used up, wastes accumulate, reproduction decreases, stays the same

Question 62

death

Answer 62

cells die faster than they are produced

Question 63

When would it be beneficial to use viable plate counts?

Answer 63

when the number of bacteria is too much

Question 64

membrane filtration

Answer 64

when you have few bacteria and lots of solution