Microbial Lifestyles and Metabolism (Dr. Kreft): Metabolism Flashcards Preview

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Flashcards in Microbial Lifestyles and Metabolism (Dr. Kreft): Metabolism Deck (38):
1

What trophic category are animals?
L> Do bacteria fit into this?

- chemotrophs
L> they use chemical reactions as energy source, organic matter as electron source, organic matter as carbon source
- Bacteria do not fit into this ....metabolism of bacteria is far more diverse ...some get electrons from inorganic compounds (H2, H2S, NH3, Fe etc)...some use CO2

2

Chemotroph?

- energy from chemical reactions e.g. oxidation of inorganic or organic compounds

3

Organotroph?

- electrons from organic matter e.g. sugar, amino acids, fatty acids, petroleum

4

Heterotroph?

- Carbon from organic matter e.g. sugars, amino acids, fatty acids, petroleum etc

5

Phototroph?

- energy from light

6

Lithotroph?

- electron from inorganic matter
eg H2, H2S, NH3, Fe

7

Autotroph?

C from CO2

8

What trophs involve energy?

- Chemotroph, phototroph

9

What trophs involve electrons?

- Organotroph
- Lithotroph

10

What trophs involve carbon sources?

- Heterotroph
- Autotroph

11

What troph are humans classified as?

-chemo-organo-heterotrophs

12

What trophs are plants classified as?

- photo-lito-autotrophs
**some phototrophic bacteria are photo-organ-hetero-trophs

13

Hydrogen bacteria burn __ and use ___ as carbon source

- H2 and use CO2
- 2H2 + O2 -->2H2O
** H2 is an electron donor, O2 is an electron acceptor..this respiration generates ATP...

14

What trophy are Hydrogen bacteria?

- chemo-litho-autotrophs

15

How many trophy combinations are actually possible? Can you have organo-auto or litho-hetero?

- 6/8
- NO neither
L> does not make sense to use organic matter for electrons and not for carbon
L> does not make sense to use inorganic for electrons and organic for carbon

16

What are the two parts of metabolism?

1. Catabolism
2. Anabolism

17

Explain catabolism and anabolism relationship!

- catabolism(breaking down) supplies anabolism( biosynthesis) with ATP, NADPH if needed (if C source more oxidized than biomass)
- carbon source + ATP= ADP + Pi --> Biomass (anabolism)
- energy source= ADP+ Pi= ATP and waste (catabolism)
**the energy and carbon source can be the same

18

What is SLP?

- substrate level phosphorylation

19

What is ETP?

- electron transport chain

20

Chemotrophs undergo what two kinds of metabolism??

1. Fermentation (aerobic sometimes, anaerobic always)
2. Respiration: aerobic and anaerobic (without presence of oxygen)

21

Phototrophs undergo what two kinds of metabolism??

- oxygenic
- anoxygenic
* like respiration but in the pop direction

22

Example of SLP?

- glycolysis
-Oxidation of aldehyde to acid coupled t o phosphorylation of acid...transfer of phosphor group to ADP...1 ATP formed.....stoichiometric coupling. If not enough delta g in a reaction then no ATP can be made, if too much delta G, surplus is wasted....no membranes needed
- No Fe needed

23

Explain the ETP respiratory chain in Paracoccus denitrificans

- Complex 1 NADH DH(yields 4H)
- Complex III Cyt bc (cyt reductase) yields 4H
- Complex IV Cyt aa (Cyt oxidase) yields 2H
- Complex V ATP Synthase -> yeilds ATP and 3.3H in the cytoplasm..not the periplasm
**ETC goes from electron donor (NADH) to electron acceptor (O2)

24

Explain the basic gist of ETP

- needs membrane to separate charge and H
- protons are pumped out through membrane
- or n protons are consumed inside and produced outside ( outside is usually higher H concentration, more positive)
- proton motive force (pmf) has two components : pH difference and membrane potential
- requires Fe
- 10 H per 3ATP (one turn of ATP synthase)
**1 H= 0.3 ATP

25

Explain Fermentation

- does not need oxygen but may take place in the presence of oxygen
-it is energy metabolism without using any external electron acceptors such as oxygen, nitrate, sulphate, Fe ...so only part of the substrate can be oxidized and the other part has to be reduced..no net gain/loss of electrons there needs to be a balance
-most form ATP via SLP but not all
-or ATP via ETP but not all

26

Is fermentation life without oxygen?

NO

27

Does fermentation not use any electron transport chains?

NO

28

Budding yeast Saccharomyces cervisiae ferments under?

- aerobic conditions if glucose is in excess
**ethanol fermentation of sugars

29

Yeast ethanol fermentation yields how many ATP per glucose?

- 2 ....alt fermentations yield more or less (1-4 ATP) more ATP if you can get rid of electrons as H2

30

Do many fermentations have branched pathways?

- yes
- high ATP branch
-low ATP branch (ATP yield variable
***many fermentations use ETP

31

Explain respiration!

- oxidation of substrate = electron donor is coupled to reduction of external electron acceptor
**Anaerobic = various other electron acceptors (NO3, Fe3+, SO4 2-, CO2
*Aerobic = just oxygen
- involves ETP and SLP
- 38 ATP per glucose
- needs external electron acceptor
- Fe is needed for cytochromes (FeS)

32

Paracoccus denitrificans is a relative of what?

- mitochondria

33

Explain phototrophs!

- light driven electron transport chain to generate proton motive force which drives ATP synthesis
-NADPH which can be used to reduce CO2 in the dark reaction
- Photons of visible light contain 100-200kJ/mol
- one single photon shifts the redox potential of (Bacterio) Chlorophyll by 1-2 V more negative

34

Phototrophs:
- reserving respiration with light energy??

- 6CO2 +6H2O --> C6H12O6 + 6O2 delta G = +2872kJ/mol
- oxidizing the reduced end products of respiration: H2O, H2S, Fe2+
- oxidizing the reduced end products of fermentation: acetate, lactate, ethanol, butyrate and hydrogen

35

Phototrophs:
- explain Oxygenic

- H2O as electron donor --> O2
- cyanobacteria (chloroplasts in plants are these)

36

Phototrophs:
- Anoxygenic?

- H2S as electron donor --> SO4 2-
- or H2, ethanol, butyrate ...
-

37

Phototrophs:
- Anoxygenic
L> Purple bacteria??

- non sulfur bacteria
- use organic electron donors and carbon sources....photo-organo-heterotrophs
-

38

Phototrophs:
- Anoxygenic?
L> Purple sulfur bacteria??

- use H2S and S as electron donor and CO2 ( or acetate) as carbon source...photo-litho-auto-trophs (if using acetate= hetero)
**Green sulfur bacteria/