AP BIOLOGY

Detailed explanation-1: -Why is oxygen essential for the electron transport chain? Explanation: Oxygen serves as the terminal electron acceptor for the electron transport chain. Electrons are donated by NADH molecules and passed through several different proteins to generate the proton gradient in the intermembrane space.

Detailed explanation-2: -Another important universal electron acceptor is FAD, a flavin nucleotide from vitamin B2. These acceptors are often used in catabolic processes and are reduced into NADH and FADH2, respectively. Glycolysis requires an input of glucose, two ATP, two ADP, and two NAD+.

Detailed explanation-3: -Both glycolysis and the citric acid cycle require NAD+ to accept electrons during their chemical reactions. In order for the cell to continue to generate any ATP, NADH must be converted back to NAD+ for use as an electron carrier.

Detailed explanation-4: -As an essential redox carrier, NAD+ receives hydride from metabolic processes including glycolysis, the TCA cycle, and fatty acid oxidation (FAO) to form NADH. NADH, therefore, serves as a central hydride donor to ATP synthesis through mitochondrial OXPHOS, along with the generation of ROS.

Detailed explanation-5: -NAD + (Nicotinamide adenine dinucleotide) is a coenzyme found in all cells. It is an electron carrier used to temporarily store energy during cellular respiration. This is found in two forms in cells: NAD+ is an oxidizing agent – it accepts electrons from other molecules and becomes reduced.