Clokie 3 Prokaryotic metabolic diversity

Question 1

Medical microbiology:

Answer 1

understanding microbial pathogenesis, toxin production, exploitation of host enzymes

Question 2

Microbiome:

Answer 2

understanding roles of ‘non-pathogenic’ microbes

Question 3

Diagnostic microbiology:

Answer 3

designing tests to detect specific metabolic intermediates & products (e.g., amylase test, catalase test, etc)

Question 4

Pharmaceutical microbiology:

Answer 4

Understanding and determining essential, specific metabolic steps allows targeting them to kill pathogens

Question 5

Biotechnology:

Answer 5

1. understanding conditions to control microbial products and to get the right fermentation pathways (biofuel, bioleaching etc)
2. exploiting specific microbial metabolic pathways for production of antibiotics, enzymes, etc…

Question 6

Foods and drugs microbiology:

Answer 6

of plant origin owe their taste, smell, active constituents to microbial metabolism.

Question 7

Environmental microbiology:

Answer 7

Fundamental understanding of biogeochemical cycling on earth

Question 8

Chemoheterotrophy:

Answer 8

– Inorganic compounds

- bacteria and archaea

Question 9

OILRIG

Answer 9

Oxidation
Is
Loss of e-

Reduction
Is
Gain of e-

Question 10

CHEMOTROPHY:

Answer 10

• Energy accessed by harnessing and linking oxidation/reduction pairs

Question 11

Oxidized form always written..

Answer 11

..on the left

Question 12

REACTION COUPLE 1
H2 ->
Becomes..
Tendency…

Answer 12

-> 2e- + 2H+
..oxidised (i.e. electron donor)
..to release e-

Question 13

REACTION COUPLE 2
O2 + 2 e- + 2H+ ->
Becomes..
Tendency..

Answer 13

-> H2O
Reduced (i.e. electron acceptor)
..to accept electrons

Question 14

REDOX POTENTIAL:

Answer 14

• Capacity of a pair to donate or accept electrons is measured by the oxidation/reduction potential (E0′)
• Measured electrically by reference to standard
Donate or accept e-

Question 15

ELECTRON TOWER

Answer 15

ANIMALS USE ORGANICS (VIA NAD, NADP)AS ELECTRON DONOR& O2 AS ELECTRON ACCEPTOR

Question 16

Prokaryotic energy source s

Answer 16

amonia, nitrate iron etc

Question 17

CHEMOHETEROTROPHS

• Have two mechanisms for energy conservation

Answer 17

– Respiration

– Fermentation

Question 18

synthesis of ATP is driven by

Answer 18

energy released in oxidation-reduction reactions

Question 19

• Respiration:

Answer 19

O2/other electron acceptor present

Question 20

• Fermentation:

Answer 20

redox has no exogenous e- acceptors

-> O2 is from internal cell

Question 21

Oxidase test

Answer 21

• Filter paper with redox dye, artificially donates an electron to cytochrome
• cytochrome system is usually only present in aerobic organisms capable of using oxygen as terminal electron acceptor
• Turns purple if dye is oxidised by oxygen released from metabolic reaction

Question 22

The redox tower of metabolism

Answer 22

ability to accept and donate must be in correct system

Question 23

Deinococci
Grow:
Habitat:
Metabolic grp:

Answer 23

• Grow on sugars, amino and organic acids/mixtures

* Aerobic thermophilic Chemoheterotrophs

Question 24

Spirochetes:
Respire:
Habitat:
Cause disease:
Morphology

Answer 24

• Aerobic/Anaerobic ferment sugars
• Widespread in aquatic environments and in animals
. syphilis (Treponema) and Lyme disease (Borrelia)
– Helical structure allows it to move in a corkscrew

Question 25

Planctomyces Respire: Metabolic grp: Strange because:

Answer 25

• Facultatively aerobic Chemoheterotrophs • Ferment or respire sugars • Lack peptidoglycan in their cell walls - membrane bound nuclear structure

Question 26

Methanotrophs and methylotrophs | Habitat:

Answer 26

Methylosinus Type I & II | Habitat: anoxic muds, marshes, lakes, rumen and intestinal tract

Question 27

Methylotrophs:

Answer 27

grow on one-carbon compounds | • can also use organic acids, ethanol, sugars

Question 28

Methanotroph

Answer 28

can also grow on methane (as well as the more oxidized one carbon compounds) • are obligate aerobes as introduce O2 into the methane molecule

Question 29

Diazotroph - N2 reduction: example

Answer 29

Azotobacter

Question 30

``` Azotobacter Respire: Metabolic grp Grow: Fix N2: Morphology: ```

Answer 30

• Obligate aerobes • Metabolism strictly oxidative • Grow on a range of carbohydrates, alcohols and organic acids • Fix N2 nonsymbiotically -> increase nitrate in soil -> used by plants Large gram –ve rods

Question 31

``` Rhizobium Metabolic grp Grow: Fix N2: Morphology: ```

Answer 31

• peas, beans, clover, and soy - N2-fixing symbiont of legumes - gram negative, motile, non-sporulating rods.

Question 32

CHEMOAUTOTROPHS:

Answer 32

- use inorganic electron donors | - most also capable of autotrophic growth – some mixotrophic

Question 33

Sources of inorganic electron donors

Answer 33

``` • Geological, biological or anthropogenic – Volcanic activity primarily H2S • Biological – H2S, H2, NH3 • Agricultural and mining esp. N and Fe – Burning fossil fuels – Input of industrial wastes ```

Question 34

Example of Fe2+ oxidation

Answer 34

• Aerobic oxidation of ferrous Fe2+ iron to ferric iron Fe3+ • Only small amounts of energy available (-32.9 kJ/reaction) Still enough to make ATP

Question 35

H2 oxidation: example

Answer 35

Aquifex

Question 36

Aquifex Metabolic grp electron donors: elcetron acceptors: Habitat:

Answer 36

* Obligate chemolithothroph and autotrophic hyperthermophile * Different species use H2, S0, S2O32- as electron donors * O2 and NO3- as electron acceptors * Grow up to 95 °C -> hot springs * Tolerates low O2 (rare for hyperthermophiles)

Question 37

NH3 and NO2- oxidation | is by

Answer 37

Nitrosifyers and Nitrifyers

Question 38

Nitrosifyers and Nitrifyers: Mainly: Habitat: Metabolic grp:

Answer 38

* Mainly Proteobacteria * Soil, water, high ammonia (e.g. sewage, contaminated lakes) * Most obligate Chemoautotrophs &obligate aerobes * No Chemoautotroph can carry out the complete oxidation from ammonia – nitrate * Ammonia oxidising (nitrosifyers) * Nitrite oxidising (nitrifyers)

Question 39

Ammonia oxidising

Answer 39

nitrosifyers

Question 40

Nitrite oxidising

Answer 40

nitrifyers

Question 41

``` Sulphur oxidising bacteria Mainly: Electron donor: Electron acceptor: Metabolic grp: Habitat: ```

Answer 41

* several Proteobacterial groups * H2S, HS, S, S2O32- * O2 as terminal electron acceptor * autotrophs (so fix CO2) * 2 groups: acid pH (some of these can also use Fe2+) or a neutral pH * Accelerate production of sulphuric acid * Large size * High motility

Question 42

Reduced Sulphur oxidizers | x3

Answer 42

Thiobacillus Thiomicrospira Thiothrix

Question 43

Reduced Sulphur oxidizers | equation

Answer 43

H2S So SO32-> SO42-

Question 44

Iron Oxidation: • Ferric iron forms... • Ferrous iron oxidises to... - metabolic grp - habitat

Answer 44

...insoluble ferric hydroxide which precipitates in water ... ferric state at neutral pH - acidophilic • Grow at pH <1 • Common in acid polluted environments • Find iron oxidisers at the interface where ferrous iron becomes oxic

Question 45

Most cultured bacteria are

Answer 45

chemoheterotrophs

Question 46

• Chemoautotrophs obtain electrons from

Answer 46

a range of inorganic donors