Bacterial Respiration, fermentation, growth Flashcards
What are the names of the 2 phases of Glycolysis?
Investment phase and Payout phase
In brief, what happens in the investment phase of glycolysis and how much ATP is spent?
6 carbon Glucose is cleaved into two 3 carbon Glyceraldehyde, 2 ATP is spent to phosphorylate during this phase.
In brief, what happens in the pay-out phase of glycolysis and how much ATP is made?
2 ATP is made for each Glyceraldehyde molecule converted to pyruvate , so per 1 Glucose molecule 4 ATP is made
What is the overall yield of a) ATP b) NADH per 1 glucose molecule of glycolysis?
a) 2 ATP (2 spent in investment phase, 4 made in pay-out phase)
b) 2 NADH (1 made per glyceraldehyde and there’s 2 per glucose molecule)
Why does glycolysis not require oxygen?
As ATP is produced by substrate-level phosphorylation not by an electron transport chain which requires a terminal electron acceptor.
What is substrate phosphorylation?
When a phosphate group is directly transferred to ADP.
Where does glycolysis occur in eukaryotic cells?
In the cytoplasm
What are the products of the link reaction?
One molecule of NADH is formed per pyruvate (so 2 NADH per glucose)
What is the process of the link reaction?
Pyruvate from glycolysis is decarboxylated to Acetyl CoA (releasing CO2 and NADH)
What is the yield of a) ATP b) NADH c) FADH2 produced from the Krebs cycle from one cycle and from 1 Glucose molecule?
a) Per 1 cycle: 1 ATP
>Per 1 Glucose molecule: 2 ATP
b) Per 1 cycle: 3 NADH
>Per 1 Glucose molecule: 6NADH
c) Per 1 cycle: FADH2
>Per 1 Glucose molecule: 2 FADH2
Why are there 2 cycles of the Krebs cycle per 1 glucose molecule?
There are 2 cycles per glucose molecule as 2 mol of pyruvate will be present from the link reaction.
What are the overall yields of a) ATP b) NADH c) FADH2 from glycolysis, link reaction, and Krebs cycle per 1 glucose molecule and what are they used for?
a) 4 ATP (2 from Krebs and Glycolysis)
>Stored as energy
b) 10 NADH (6 from Krebs, 2 from Link, 2 from Glycolysis)
>Used in ETC due to high reducing power (act as electron carrier molecules)
c) 2 FADH2 (both from Krebs)
>Used in ETC due to high reducing power (act as electron carrier molecules)
What are Quinones?
Quinones are lipophilic molecules (hydrophobic) found in membrane which carry electrons
How many electrons and protons are required to reduce a quinone to a quinol ?
2 Electrons and 2 Protons
What type of anaerobe are E.coli?
Facultative anaerobe
What does it mean that E.coli are facultative anaerobes?
Means if O2 is present does aerobic respiration (allows full oxidation of growth substrate, maximal conserved energy as O2 as terminal electron acceptor) but if it isn’t either anaerobic respiration or fermentation occur.
When would a) Aerobic respiration b) Anaerobic respiration c) Fermentation occur in E.coli?
a) In presence of oxygen
b) No oxygen, but in presence of alternative terminal electron acceptor
c) No oxygen or alternative terminal electron acceptor.
Where do both glycolysis and the Krebs cycle occur in E.coli and how does this differ to eukaryotic cells?
Both processes occur in the cytoplasm (different to eukaryotes as glycolysis occurs in the cytoplasm and Krebs in the mitochondria)
Where is the periplasm found?
Periplasm is between outer and inner membrane.
Where is the a) Positive (p/+) b) Energetic c) Negative (n/-) areas for the ETC in E.coli?
a) Periplasm is positive
b) Inner membrane is energetic membrane
c) Cytoplasm is negative
What is meant by the inner membrane being the “energetic membrane” in the ETC in E.coli?
Inner/ cytoplasmic membrane is energetic membrane, where the ETC is localised and the proton gradient/ proton motive force is built up to drive ATP synthesis.
In terms of the periplasm, inner/cytoplasmic membrane, and cytoplasm, what is the movement of H+ throughout the ETC in E.coli?
H+ pumped from cytoplasm (N side, contains less H+) to periplasm (P side, contains more H+), moves back through to cytoplasm via ATP synthase in inner membrane (down conc gradient)
What are NADH dehydrogenase complex I and Succinate dehydrogenase complex II examples of?
Electron donor complexes in eukaryotes.
What are the electron donor complexes alternatives to a) Complex I (NADH dehydrogenases) b) Complex II (succinate dehydrogenase) in E.coli?
a) Nuo and Ndh (NADH dehydrogenases)
b) SDH (succinate dehydrogenase)