Biomi 2900 Wk 6

Front 1

Describe: cell wall

Back 1

1. bacterial cell wall composed of peptidoglycan
2. NAG and NAM are two major subcomponents of peptidoglycan

Front 2

Describe: cell wall synthesis

Back 2

1. precursor molecules formed in cytoplasm
2. bactoprenol tethers the precursors and flips them across to the outside of the membrane
3. precursors are added to existing cell wall by transglycosylases and crosslinked by transpeptidases

Front 3

What is important about antibiotics role in the study of cell wall synthesis?

Back 3

1. vancomycin and penicillin
2. they interefere with crosslinking

Front 4

Define: purine

Back 4

1. two fused rings
2. aromatic compound that comprises of two groups of nitrogenous bases

Front 5

Define: pyrimidines

Back 5

1. one ring
2. aromatic compound that comprises of two groups of nitrogenous bases

Front 6

What is the initial purine formed?

Back 6

inosine

Front 7

What is the initial pyrimidine formed?

Back 7

uracil

Front 8

Define: tetrapyrroles

Back 8

compounds that contain four pyrrole rings; have different tail structures

Front 9

Define: pyrrole

Back 9

five-membered aromatic

Front 10

Describe: tetrapyrrole synthesis

Back 10

1. pyrroles are made via glutamate or glycine-succinate pathway
2. four pyrroles are then condensed and cyclized

Front 11

Describe: microbial growth

Back 11

1. can be extremely fast or slow
2. binary fission/division model

Front 12

Growth rate/ division rate

Back 12

1. change in the number of bacteria per unit time
2. r = 1 dt

Front 13

Doubling time/ generation time

Back 13

1. time it takes for a bacterial population to double
2. dt = t/n (n = # of doublings)

Front 14

what does n equal?

Back 14

n = log Nfinal - log Ninitial / log 2

Front 15

Describe: parts of a bacterial growth curve

Back 15

1. logarithmic
2. 4 distinct phases: lag, log, stationary, and death

Front 16

Describe: lag phase

Back 16

1. horizontal line
2. no growth
3. due to cells being acclimated to new medium

Front 17

Describe: log phase

Back 17

1. upward-sloping line
2. perfect balance with new growth medium
3. grow rapidly

Front 18

Describe: stationary phase

Back 18

1. horizontal line
2. no growth
3. due to depleted nutrients and/or toxin accumulation
4. if growth medium is refreshed, growth will most likely resume

Front 19

Describe: death phase

Back 19

1. downward-sloping line
2. not as steep; slowly die
3. bacterial cells are smaller and tougher to kill (due to the unfavorable growth medium)

Front 20

Describe: endospores

Back 20

1. formed by Gram (+) cells
2. used to deal with depleting resources
3. environmentally resistant

Front 21

What are normal growth conditions?

Back 21

1. 20-40 degrees
2. 7pH
3. a bit of salt
4. plenty of nutrients
5. sea level

Front 22

What are 5 factors that influence microbial growth the most?

Back 22

1. temperature
2. pH
3. salinity
4. oxygen concentration
5. radiation
6ish - pressure

Front 23

What are the four temperature classes?

Back 23

1. psychophiles
2. mesophiles
3. thermophiles
4. hyperthermophiles

Front 24

Describe: psychophiles

Back 24

1. prefer cold temperatures
2. inhabit sea ice, glaciers, Antarctica, snow etc.
3. enzymes are active at cold temperatures
4. active transport carried out at cold temps
5. more unsaturated fatty acids in membrane

Front 25

Describe: mesophiles

Back 25

prefer moderate temperatures (10 -45 deg)

Front 26

Describe: thermophiles

Back 26

prefer hot temperatures ( >45 deg)

Front 27

Hyperthermophiles

Back 27

1. prefer extremely hot temperatures (>80 deg)
2. nearly all are archaeans
3. inhabit deep thermal vents, hot springs, and oil wells
4. DNA stabilized (MP increased)
5. enzymes stabilized by salt bridges and H bonding
6. more saturated fatty acids

Front 28

Describe: Halophiles

Back 28

1. microbes that necessitate high salt concentrations
2. H. salinarum - an extreme one

Front 29

Describe: salinity as a major factor affecting microbial growth

Back 29

1. high salinity = low water activity
2. how much water is available, which is induced by salt concentration, is what is important
3. high salt env. puts microbes under high osmotic stress

Front 30

Describe: hypertonic environment

Back 30

1. salt concentration is high outside of cell
2. water inside cell will diffuse out
3. to cope, bacteria will produce or take in solute to balance gradient and reduce osmotic stress
4. or it will shrivel and die

Front 31

Describe: hypotonic environment

Back 31

1. salt concentration is low outside of cell
2. water outside cell will diffuse in
3. to cope, bacteria will leak solute to balance gradient and reduce osmotic stress
4. or it will burst

Front 32

Describe: aquaporins

Back 32

1. transmembrane transporter that allows for water to enter/exit cell quickly
2. relieve microbes of high osmotic stress

Front 33

Describe: acidophiles

Back 33

1. prefer acidic environments
2. 0 - 6 pH
3. advantage: can generate a PMF from the high proton concentration (from environment)

Front 34

Describe: alkaliphiles

Back 34

1. prefer basic environment
2. pH 8-14
3. inhabit soda lakes

Front 35

Describe: effect of pH on microbial growth

Back 35

1. microbes are in constant struggle to maintain internal pH
2. microbe can be killed by drastic change in pH

Front 36

Describe: Na+/H+ anti porter system

Back 36

1. used in very basic conditions (high pH)
2. help keep microbes internal pH lower than external pH
3. 2 Na+ transported out for every H+ ion take in

Front 37

Describe: citric acid in pH homeostasis

Back 37

1. permeate the cell membrane of microbial cells
2. acid dissociates and release H+
3. depress internal pH

Front 38

Describe: facultative anaerobes

Back 38

1. E.coli
2. make ATP via aerobic respiration when O2 present
3. make ATP via fermentation when O2 absent

Front 39

Describe: microaerophiles

Back 39

1. use O2, but at low concentrations

Front 40

Describe: aerotolerant

Back 40

1. tolerates O2 at all concentrations
2. not effected by O2

Front 41

Describe: anaerobe

Back 41

only grow when O2 is absent

Front 42

What are the protective enzymes that allow microbes tolerate O2? Without these, the microbes that can't tolerate O2 die

Back 42

1. catalase
2.peroxidase
3. superoxidase
4. dismutase

Front 43

Describe: Fenton reaction

Back 43

1. toxic to microbes
2. reaction b/w H2O2 and Fe+2 to form OH- and radical OH

Front 44

How to maintain an anoxic environment?

Back 44

1. reducing agents or enzyme systems
2. culture an anaerobe jar
3. gas sparging
4. anaerobic chamber with glove parts

Front 45

Describe: harmful radiation

Back 45

1. harmful radiation starts at wavelengths less than 400nm
2. UV damages DNA and proteins (UV used to sterilize)
3. gamma rays break DNA molecules by stripping away electrons

Front 46

Describe: methods to limit/eliminate microbial growth

Back 46

1. antisepsis
2. disinfection
3. sterilization
4. sanitation
5. irradiation
6. pasteurization

Front 47

Describe: antisepsis

Back 47

removal of pathogens from living tissue

Front 48

Describe: disinfection

Back 48

removal of pathogens from inanimate surfaces

Front 49

Describe: sterilization

Back 49

elimination of all living things

Front 50

Describe: sanitation

Back 50

reduction of microbial presence to healthy levels

Front 51

Describe: irradiation

Back 51

1. UV, gamma, Xrays used to kill microbes
2.D. radiodurans is resistant to irradiation because it has multiple copies of its genome

Front 52

Describe: pasteurization

Back 52

microbes are subjected to high temperatures for a definite time period, and then cooled immediately

Front 53

Things to keep in mind when using a chemical agent against microorganisms

Back 53

1. presence of organic matter
2. types of microbes present
3. corrosiveness of chemical
4. stability, odor, and surface tension

Front 54

Describe: antibiotics

Back 54

1. compounds secreted and made by microbes to kill or inhibit growth of other microbes
2. bacteriocidal -lethal antibiotics
3. bacteriostatic- non lethal antibiotics (inhibit growth and reproduction by interfering with DNA and protein replicate, ex: tetracyclin)

Front 55

Describe: ampicillin

Back 55

1. affects peptidoglycan cross-linking in E.coli
2. too much will degrade the cell wall, causing the cell to become more susceptible to osmotic stress

Front 56

Describe: probiotics

Back 56

microbes that restore balance to one's gut microflora

Front 57

Describe: phage therapy

Back 57

treats infectious disease with viruses targeted to the pathogen

Front 58

assimilation

Back 58

acquisition of an element

Front 59

dissimilation

Back 59

breakdown and release of elements

Front 60

Describe: 10 percent rule

Back 60

1. only 10%of biomass is transffere to subsequent trophic levels
2. the rest of the 90% is respired off as CO2
3. ex: primary produces (uses 100% of energy); grazer (uses 10% of pp energy); predator (uses 1% of pp energy)

Front 61

define: chemoclines

Back 61

1. nutrient gradients within a small-scale environment
2. different organisms can live and fulfill different niches

Front 62

symbiosis

Back 62

close association between two organisms of different species

Front 63

Describe: mutualism

Back 63

1. symbiotic relationship where both organisms benefit from the benefit of the other
2. sometimes dependent for other to survive
3. ex: lichens

Front 64

Describe: lichens

Back 64

1. fungal-algal or fungal-cyanobacterial relationships

Front 65

syntrophy

Back 65

1. cross feeding
2. organisms live off products of an other organism

Front 66

syngergism

Back 66

optional cooperation of organisms

Front 67

communalism

Back 67

one organism benefits, the other unaffected

Front 68

amensalism

Back 68

one organism is harmed, but the relationship is not close

Front 69

Division of ocean zones

Back 69

1. neuston
2. euphotic zone
3. aphotic zone
4. benthic zone

Front 70

Because oceanic microbes are uncultured, how do scientists determine microbial makeup?

Back 70

using metagenomic analysis

Front 71

Describe: metagenomic analysis

Back 71

reveals what kinds of microbes are present and what types of metabolic processes are going on

Front 72

Describe: mixtrophs

Back 72

1. organisms capable of both phototrophy and heterotrophy
2. metabolically versatile and complicate food webs

Front 73

soil layers

Back 73

1. organic horizon
2. aerated horizon
3. eluviated horizon
4. bedrock

Front 74

what kind of relationship do microbes have with soil?

Back 74

symbiotic