Question

Энергетический обмен в клетке

Answer 1

Энергетический обмен - катаболизм, диссимиляция.
Совокупность реакций расщепления сложных органических в-в, до более простых с последующем выделением АТФ. 
Выделение АТФ происходит различными способами - анаэробно(без участия кислорода) и аэробно(с участием кислорода).

Answer 2

Energy Exchange in Cells

Energy exchange in cells refers to the processes by which cells obtain and utilize energy to carry out their various functions. The primary currency of energy in cells is adenosine triphosphate (ATP), which is produced through cellular respiration. Cellular respiration involves the breakdown of glucose and other organic molecules to release energy in the form of ATP.

Cellular Respiration: Cellular respiration is a series of metabolic reactions that occur in the mitochondria of cells. It involves the oxidation of glucose and other organic molecules to produce ATP. The process can be summarized in three main stages: glycolysis, the Krebs cycle (also known as the citric acid cycle or TCA cycle), and oxidative phosphorylation.

1. Glycolysis: Glycolysis is the initial step of cellular respiration and takes place in the cytoplasm of the cell. It involves the breakdown of glucose into two molecules of pyruvate, producing a small amount of ATP and reducing equivalents in the form of NADH.

2. Krebs Cycle: The pyruvate molecules produced in glycolysis enter the mitochondria, where they are further broken down in the Krebs cycle. This cycle generates reducing equivalents in the form of NADH and FADH2, as well as a small amount of ATP.

3. Oxidative Phosphorylation: The reducing equivalents (NADH and FADH2) generated in glycolysis and the Krebs cycle are used in oxidative phosphorylation to produce the majority of ATP. This process occurs in the inner mitochondrial membrane and involves the transfer of electrons through a series of protein complexes known as the electron transport chain (ETC). As electrons move through the ETC, energy is released and used to pump protons across the membrane, creating an electrochemical gradient. The flow of protons back across the membrane through ATP synthase drives the synthesis of ATP.

NADH and NAD+: NADH (nicotinamide adenine dinucleotide) and NAD+ (oxidized form of NADH) play a crucial role in cellular respiration. NADH is produced during glycolysis and the Krebs cycle as a result of the oxidation of glucose and other organic molecules. It carries high-energy electrons that are used in oxidative phosphorylation to generate ATP.

NADH can be converted back to NAD+ through the process of oxidative phosphorylation. This conversion allows NADH to continuously participate in cellular respiration and produce ATP. The ratio of NAD+ to NADH is important for maintaining the proper functioning of cellular respiration.

In addition to its role in cellular respiration, NAD+ is also involved in other metabolic processes, such as DNA repair and the regulation of gene expression.

Conclusion

Energy exchange in cells is a complex process that involves cellular respiration and the production of ATP. Glycolysis, the Krebs cycle, and oxidative phosphorylation are the key steps in cellular respiration. NADH and NAD+ play a crucial role in this process by carrying high-energy electrons and participating in ATP production.