AP BIOLOGY

Detailed explanation-1: -In each of the enzymatic reactions, NAD+ accepts two electrons and a H+ from ethanol to form NADH.

Detailed explanation-2: -NAD+ to NADH transformation When NAD+ takes an electron from glucose, it becomes NADH, the reduced form of the molecule. NADH transports this electron to mitochondria where the cell can take the energy that is stored in the electron. NADH then donates the electron to oxygen, converting it back to NAD+.

Detailed explanation-3: -Thus, the malate–aspartate shuttle is reversible and requires multiple enzymes. In this shuttle, NADH is oxidized to NAD+ in the cytosol and NAD+ is reduced to NADH in mitochondria.

Detailed explanation-4: -NAD+ accepts electrons from food molecules, transforming it into NADH. NADH donates electrons to oxygen, converting it back to NAD+. The relative proportion of these two molecules depends on the energy state of the cell, with more NADH being present in a fed state.

Detailed explanation-5: -Electrons from NADH enter the electron transport chain in complex I, which consists of nearly 40 polypeptide chains (Figure 10.8). These electrons are initially transferred from NADH to flavin mononucleotide and then, through an iron-sulfur carrier, to coenzyme Q-an energy-yielding process with