Distinguish between the following: (a) Aerobic respiration and Anaerobic respiration (b) Glycolysis and Fermentation (c) Glycolysis and Citric acid Cycle

Aerobic respiration uses oxygen (O₂) as the terminal electron acceptor in the electron transport chain; anaerobic respiration uses inorganic molecules other than O₂ (e.g., nitrate, sulfate, fumarate) as terminal acceptorsAerobic respiration fully oxidizes substrates to CO₂ and H₂O, yielding ~30–32 ATP per glucose; anaerobic respiration yields less ATP (varies by acceptor, often 2–20 ATP) and produces reduced end‐products (e.g., NO₂⁻, H₂S, CH₄)

In eukaryotes, aerobic respiration occurs in mitochondria (matrix and inner membrane), whereas anaerobic respiration operates wherever the relevant reductases are located (often cytosol or plasma membrane)

Glycolysis is a ten‐step pathway in the cytosol that converts one glucose into two pyruvate molecules, yielding a net 2 ATP and 2 NADH by substrate‐level phosphorylation

Fermentation consists of glycolysis plus specific reactions that regenerate NAD⁺ by reducing pyruvate (or derivatives) to organic products (e.g., lactate, ethanol), with no additional ATP beyond the 2 from glycolysis

Glycolysis operates under both aerobic and anaerobic conditions; fermentation only occurs when O₂ is unavailable and serves solely to recycle NAD⁺

Glycolysis occurs in the cytosol, is linear, and yields per glucose: 2 ATP, 2 NADH, and 2 pyruvate

Citric acid cycle takes place in the mitochondrial matrix, is cyclic, and per acetyl-CoA yields: 3 NADH, 1 FADH₂, 1 GTP (ATP), and 2 CO₂

Glycolysis does not require oxygen directly; citric acid cycle depends indirectly on O₂ since its NADH/FADH₂ products must be reoxidized by the electron transport chain