Chapter 7B - Microbial Metabolism: Fermentation & Respiration Flashcards
What type of energy is used to accomplish work in the cell?
Chemiosmotic potential
The chemiosmotic potential that releases energy during ionic movement
Many active-transport reactions and the rotation of the prokaryotic flagellum are drivement by the movement of ________ down a concentraiton gradient.
Ions
The chemiosmotic potential that releases energy during ionic movement is due to the ________________ of the cell being more acidic and more positively charged relative to the ____________ of the cell.
Exterior
Interior
What are two ways in which a chemiosmotic potential can be made?
- Electron transport systems (respiratory or phototrophic cells)
- ATP synthase
A chemiosomotic potential can be made in two ways: electron transport chain or ____________, both of which pump ions across a membrane. However, ___________ can work in opposite direction, too.
ATP synthases/ATPases
The ______________ of the cell tends to be more positively charged and the _____________ of the cell tends to be less positively charged.
Surface
Inside
_____________________ is the movement of ions across a semipermeable membrane down their electrochemical gradients.
Chemiosomosis
_____________________ refers to catabolic reactions producing ATP in which organic or inorganic compounds are primary electron donors and organic or inorganic compounds are ultimate electron acceptors; oxidation of a compound occurs with a terminal electron acceptor that is usually accompanied with ATP synthesis via oxidative phosphorylation.
Respiration
________________________ refers to catabolic reactions producing ATP in which organic compounds serve as primary electron donor and electron acceptor; ATP is produced by substrate-level phosphorylation; and there is no need for external electron acceptors.
Fermentation
Is glycolysis a type of fermentation or respiration?
Fermentation
The simplest and probably the oldest form of energy metabolism is _____________________ in which ATP is generated by substrate-level phosphorylation and ATP synthase functions in the direction of ATP hydrolysis to generate a protonic potential.
Fermentation
What is the basic strategy of fermentation?
The transfer of inorganic phosphate to a high-energy organic compound that can then be used to create ATP via substrate-level phosphorylation
In order for substrate-level phosphorylation to occur via fermentation, the phosphate has to be added to the organic compound as a “low-energy” phosphate, like in __________________________, and then converted to a “high-energy,” like in phosphoenolpyruvate (PEP).
2-phosphoglycerate
Fermentation produces end products at the same average _____________ level as the substrates.
Redox
Do all fermentations require redox reactions?
No; there are a few that do not in which the chemistry is such that a substrate-level phosphorylation can occur without any oxidation of the organic substrate
Three different strategies are used to incorporate oxidation reactions into fermentation pathways. What are they?
- Part of the substrate molecule is oxidized and part of it is reduced
- The substrate is first oxidized and then the oxidized intermediate is reduced
- Two different substrates are used, one being oxidized and the other being reduced
What is the goal of homolactic fermentation?
To regenerate NAD+
In _______________________ fermentation, glucose is oxidized to pyruvate, producing ATP and NADH, and the NADH is reoxidized by reducing pyruvate to _____________.
Homolactic
Lactate
What is the goal of ethanol-acetate fermentation?
To produce ATP
In _____________________ fermentation, one branch produces ATP while the other reoxidizes NADH.
Ethanol-acetate
What is the goal of Strickland fermentation?
To produce ATP
In ____________________ fermentation, one amino acid (alanine in this case) is oxidized to produce ATP while another amino acid (glycine in this case) is reduced to reoxidize NADH).
Strickland
A common fermentation of the amino acid ___________________ involves non-oxidative or reductive rearrangements and cleavage to produce ornithine and the high-energy compound carbamoyl phosphate, which can transfer its phosphate to ADP.
Arginine
