best describe energy release in a cellular respiration
The energy release in cellular respiration refers to the process by which cells break down organic molecules, such as glucose, to produce ATP (adenosine triphosphate), the main energy currency of cells. This process involves a series of interconnected biochemical reactions, including glycolysis, the Krebs cycle (or citric acid cycle), and oxidative phosphorylation.
During glycolysis, glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH, a coenzyme that carries high-energy electrons. The pyruvate then enters the mitochondria, where it undergoes further oxidation in the Krebs cycle. This cycle generates more NADH and FADH2, which are electron carriers.
The energy stored in NADH and FADH2 is then transferred to the electron transport chain, a series of protein complexes located in the inner membrane of the mitochondria. As electrons flow through the electron transport chain, energy is released, which drives the pumping of protons (H+) across the membrane, creating an electrochemical gradient.
The flow of protons back across the membrane through ATP synthase drives the synthesis of ATP through a process called oxidative phosphorylation. This final step of cellular respiration is responsible for the majority of ATP production, as each molecule of NADH can generate up to three ATPs, and FADH2 can generate two ATPs.
Overall, cellular respiration is an efficient process that releases energy from glucose in the form of ATP, which can then be used by cells to carry out essential functions such as muscle contraction, active transport, and protein synthesis.