What are the energy intermediates in cellular respiration?

The energy intermediates in cellular respiration are adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NADH), and flavin adenine dinucleotide (FADH2).

Cellular respiration is a set of metabolic reactions that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break down large molecules into smaller ones, releasing energy in the process. This energy is stored in the form of energy intermediates, primarily ATP, NADH, and FADH2.

ATP, or adenosine triphosphate, is often referred to as the 'energy currency' of the cell. It is a high-energy molecule that stores the energy we need to do just about everything. In the process of cellular respiration, ATP is produced in the mitochondria through a process called oxidative phosphorylation. This process uses the energy released by the oxidation of nutrients to produce ATP.

NADH and FADH2 are both electron carriers. They play a crucial role in the electron transport chain, a series of protein complexes embedded in the inner mitochondrial membrane. NADH and FADH2 donate their electrons to this chain. The energy released from these electrons is used to pump protons across the inner mitochondrial membrane, creating a proton gradient. This gradient is then used to drive the synthesis of ATP.

NADH is produced in glycolysis and the Krebs cycle, the first two stages of cellular respiration. FADH2, on the other hand, is only produced in the Krebs cycle. Both of these molecules carry high-energy electrons that were originally part of glucose. When these electrons are transferred to the electron transport chain, their energy is used to power the production of ATP.

In summary, ATP, NADH, and FADH2 are the main energy intermediates in cellular respiration. They play a crucial role in storing and transferring the energy released from the breakdown of nutrients.