Environmental factors and growth

Question 1

Where can they grow

Answer 1

• inside gut
• in soil
• in fresh water lake
• in root of legume
• Food production

Question 2

What do they need nutrient for

Answer 2

• energy
• biosynthesis
• growth (reducing power, CO2, hydrogen and e- to organi molecules also support energy & biosynthesis)

Question 3

95% of any cell consists of only a few macronutrients:

Answer 3

[ dry weight from high to low]

Carbon, oxygen, nitrogen, hydrogen, phosphorous, sulphur

Question 4

macronutrients needed for component of

Answer 4

lipid, carbohydrate, protein, nucleic acids

Question 5

Other macronutritents and function

Answer 5

Magnesium - Enzyme co factors, complex ATP, stabilises ribosomes and membranes

Iron - Electron transport, enzyme co-factors

Calcium - endospore heat resistance and many roles

Potassium - enzyme activity

Question 6

Trace elements needed

Answer 6

Cobalt, zinc, Manganese, Nickel, copper, molybdenum

Question 7

if anything limiting in macro or micronutrients, microbes would

Answer 7

growth would stop

Question 8

varied fueling reactions

Answer 8

CO2 > carbon source
Organic compounds > energy , carbon source, electron
Light > energy source

Question 9

Organic carbon can derive from ______ ; can be used by __________ as _________ (3)

Answer 9

eg glucose, fatty acids, amino acids

heterotrophy bacteria

Used as:
- backbone for all cellular components (along with H & O)
- energy source - for fermentation or respiration
- supplies electrons
= CHO + O2 > CO2 + H2O + e-
= Reduced carbon, more energy (e-)

Question 10

often preferred C-source

Answer 10

Glucose

Question 11

which can use over 100 different C- compounds

Answer 11

Burkholderia cepacia

Question 12

Many common soil bacteria can utilise unusual compounds such as

Answer 12

pesticides, rubber, antibiotics

Question 13

Others highly, restricted like -Leptospira use only_______ for C source

Answer 13

long chain fatty acids

Question 14

What is inorganic carbon ?
can be used by ________
fixed by ________ or ___________

Answer 14

Inorganic carbon (CO2) > a source of carbon
autotrophy bacteria

• Must be reduced (fixed) for incorporation into cell building blocks
• Fixed in photosynthesis: CO2 + H2O > CH2O + O2
  or chemically: CO2 + H2S > CH2O + S

Fixation is an expensive process, NOT a source of energy, needs an alternate source of energy (eg light)

Question 15

Glucose is a source of

Answer 15

Carbon, hydrogen, oxygen

Question 16

Cysteine is a source of

Answer 16

Carbon, hydrogen, oxygen, sulphur, nitrogen

Question 17

Carbon dioxide is a source of

Answer 17

Carbon, oxygen

Question 18

The sources of nutrients- Nitrogen compose organic/ inorganic molecules ? examples

Required for

Answer 18

-Organic molecules

• ammonia [can be incorparted into amino acid synthesis]
• nitrate (NO3-), which can reduce to ammonia (NH4+) via nitrate reduction
• Nitrogen gas via nitrogen fixation (N2 to NH3) eg Rhizobium in plants - nitrogenase

protein, nucleic acid, some lipids, carbohydrate

Question 19

~50% of all nitrogen fixation is in ________ by _______

Answer 19

oceans, eg Cyanobacteria

Question 20

Sources of nutrients: Phosphorus absorbed as __________

Sulphur absorbed as __________

Answer 20

Mostly absorbed as inorganic phosphate

Generally absorbed as sulphate (SO42+) and reduced (Assimilatory sulphate reduction)

Question 21

Nutritional types of microbes

Answer 21

Define organisms by their carbon, energy and electron sources

Question 22

Bacteria used reduced, preformed organic compounds as source of carbon

Answer 22

Heterotrophs

Question 23

Autotroph

Answer 23

use CO2 main or only source of carbon

Question 24

Nutritional types of microbes (Energy source)

Answer 24

Phototrophs- Make energy using LIGHT

Chemotroph - Make energy from CHEMICALS

Question 25

Nutritional types of microbes (Electron source)

Answer 25

Lithotrophs (‘rock eaters’) - Reduced inorganic compounds. eg H2S, H2, NH4+, NO2 – ,Fe2+ Organotrophs -Organic molecules eg glucose

Question 26

Thiobacillus denitrificans uses____ as electron donor and _____ as electron acceptor, products __________

Answer 26

H2S as electron donor NO3- as electron acceptor produce SO42- and N2

Question 27

Photolithoautotrophs (identify and example)

Answer 27

Light, Inorganic H2/e-, CO2 e.g. Cyanobacterium: Light, CO2, H2O

Question 28

Chemolithoautotrophs (identify and example)

Answer 28

Inorganic chemical, Inorganic H2/e-, CO2 e.g. Thiobacillus: Elemental sulphur or Sulphide (H2S) and CO2

Question 29

Chemoorganoheterotrophs (identify and example)

Answer 29

Organic carbon, Organic H2/e- , C organic Micrococcus, Staphylococcus and most pathogenic bacteria: Glucose + a huge variety of other C sources

Question 30

Many organisms need only the basics: _________ for growth as they have _________ Others cannot make everything from scratch, must obtain compounds from _____________

Answer 30

C, H, N, O P, S, energy and minerals Have all pathways and enzymes needed from environment/ media

Question 31

Bacteria growth factors

Answer 31

eg Amino acids, purines, pyrimidines, vitamins | [Common in host associated pathogens]

Question 32

Chemical and physical environment

Answer 32

nutrients / Temperature / salinity / pressure

Question 33

Prokaryotes can live almost anywhere - Most survive in “normal” conditions of _____________

Answer 33

water, pH and temperature

Question 34

Extremophiles

Answer 34

High temperature, salinity, pressure, pH, anoxia

Question 35

Plasma membrane separates microbe from environment

Answer 35

= Affected by external osmotic pressure - Hypotonic and hypertonic effects = Use compatible solutes to control turgor = Cell wall maintains shape = Protists use exclusion bodies in cells

Question 36

Water activity

Answer 36

a measure of water availability and it can limit growth aw = Relative Humidity/100 Water isn’t always available even when present - Some is bound to solutes (osmotic effect) : High solute concentrations reduce aw - Some is bound to solids (matrix effect)

Question 37

aw 0.55

Answer 37

DNA is disordered, lower limit of life

Question 38

aw 0.85- 0.80

Answer 38

Salami, preserves Saccharomyces, Staphylococcus, Penicillium

Question 39

aw 0.98- 1.00

Answer 39

Blood, fresh veg, meat, seawater Many microbes

Question 40

halophilic

Answer 40

(salt-loving) | Halobacterium - 2.8 M to 6.2 M (saturation)

Question 41

halotolerant

Answer 41

(salt-tolerant) | Staphylococcus aureus - up to 3M NaCl (aw= 0.85)

Question 42

Osmotolerant

Answer 42

``` (high osmotic pressure) Saccharomyces rouxii (aw = 0.60) ```

Question 43

Adaptation to high salt

Answer 43

[NaCl conc. (M)] Non halophile : 0- 1M (op. 0M) Halotolerant : 0-3M (op. 0M) Moderate halophile : 0.1-3.5M (op. 2M) Extreme halophile : 2- 4M (op. 4M)

Question 44

Microbes grow from pH __ to ___

Answer 44

from pH 10 Neutrophiles pH 5.5 - 8 (most organisms) Acidophiles pH 0 - 5.5 Alkalophiles pH 8.5 - 11.5 BUT all maintain an internal pH of 5.5 - 8

Question 45

Temperature ______ speed up reactions Increasing temperature / Low temp effects

Answer 45

increase ; 10°C increase doubles reaction rates Increasing temperature damages cells - Denatures enzymes and disrupts membranes Low temp stops growth- Solidifies membranes and enzymes, freezing can kill cells

Question 46

Cardinal temperatures

Answer 46

(minimum, maximum and optimum temp for maximum growth) E. coli (approx:10°C, 37°C, 45°C) Low: Bacillus psychrophilus (-10°C, 24°C, 30°C ) High: Pyrolobus fumarii (90°C, 106°C, 113°C) Limit ~ 140°C (ATP degrades)

Question 47

Psychrophilic

Answer 47

cold-loving (-2 to 20°C)

Question 48

Mesophilic

Answer 48

“normal” (15 to 45°C)

Question 49

Thermophilic

Answer 49

High temp (max 55-80°C)

Question 50

Hyperthermophilic

Answer 50

Very high temp (80-113°C)

Question 51

Define bacteria by environment temp

Answer 51

Psychrophilic Mesophilic Thermophilic Hyperthermophilic

Question 52

What am I? 1. Escherichia coli - lives in human gut 2. Methanococcoides burtonii - from an Antarctic lake 3. Pyrococcus abyssi - from a deep-sea hydrothermal vent 4. Thermus aquaticus - Source of PCR enzyme taq, used at 72°C

Answer 52

1. Mesophile 2. Psychrophile 3. Hyperthermophile 4. Thermophile

Question 53

Effect of Oxygen Concentration

Answer 53

Obligate aerobes - Must have O2 (Pseudomonas aeruginosa) Facultative anaerobes - Grow better if O2 present (E. coli) Microaerophiles - Low O2 (2-10%, Campylobacter pylori) (atmospheric O2 (~20%) [common among pathogens] Obligate Anaerobes - No O2 at all (Clostridium botulinum) Aerotolerant anaerobes - Ignore O2 (Lactobacillus casei)

Question 54

Other environmental factors

Answer 54

Pressure Radiation

Question 55

Pressure for bacteria

Answer 55

Deep sea pressure can be >1000 Atm, 2*C Barotolerant and barophilic (require high pressure) microbes Hyperthomophiles also require high pressures.

Question 56

Radiation

Answer 56

- Both visible and invisible. As wavelength decreases, energy increases - damages DNA induce mutations (UV of wavelength 260 is most lethal. Micrococcus sp. and Haloarchaea have pigments to screen UV Deinococcus radiodurans - survive ionising radiation at high levels - Grows in nuclear reactors

Question 57

adaptations of thermophiles

Answer 57

protein structure stabilized by more H bonds /more proline / chaperones histone-like proteins stabilize DNA membrane stabilized by more saturated, more branched and higher molecular weight lipids / ether linkages (archaeal membranes)