Carbon Catabolism and Electron Flow in Organotrophy

These flashcards cover essential concepts about carbon catabolism, glycolysis, fermentation, the electron transport system, and ATP synthesis, aligning with the provided lecture notes.

What is catabolism?

Catabolism refers to reactions that break down larger molecules into smaller molecules and energy intermediates.

What is metabolism comprised of?

Metabolism is the sum of catabolism and anabolism.

What is the purpose of glycolysis?

Glycolysis breaks down sugars into pyruvate, generating ATP and NADH.

How is glycolysis regulated?

Glycolysis can be regulated through transcriptional regulation, translational regulation, modulation of protein activity, and feedback inhibition.

What are the major checkpoints in the complete oxidation of glucose?

The major checkpoint is the pyruvate dehydrogenase complex (PDC), which links glycolysis with the TCA cycle.

How does fermentation occur?

Fermentation occurs when facultative anaerobes start fermenting when oxygen demand exceeds availability, recycling NADH back to NAD+.

What is the proton motive force (PMF)?

PMF is the energy stored in a proton gradient across a membrane, used to drive cellular processes.

What influences the PMF?

The PMF is influenced by pH and ionic gradients, with ∆pH and ∆ψ contributing to proton motive force.

What are redox reactions?

Redox reactions are processes where electrons are transferred from a donor to an acceptor.

What are the enzymes required for an electron transport system (ETS)?

The ETS requires initial oxidoreductase and terminal oxidoreductase enzymes.

What is the significance of NADH in cellular respiration?

NADH transfers its electron pair into the electron transport system and is oxidized to regenerate NAD+.

How does ATP synthase function?

ATP synthase utilizes the flow of protons driven by the PMF to synthesize ATP from ADP and inorganic phosphate.

What role do electron donors and acceptors play in redox reactions?

Good electron donors are found at the top half of the redox tower, while good electron acceptors are at the bottom.

What happens to electrons in the electron transport system?

Electrons pass through various components of the ETS, leading to the pumping of protons across the membrane.

What is the process of oxidative phosphorylation?

Oxidative phosphorylation is the process by which ATP is produced via the electron transport chain and ATP synthase.

Why must all bacteria maintain pH homeostasis?

Bacteria must maintain pH homeostasis due to the dependence on proton motive force (PMF) for energy.