“As of May 5, 2026, the four main stages of catabolic metabolism are digestion (breakdown of polymers into monomers such as sugars and amino acids), glycolysis (cytoplasmic breakdown of glucose to pyruvate), the Krebs cycle (mitochondrial oxidation of acetyl-coenzyme A), and oxidative phosphorylation (electron transport chain coupled to adenosine triphosphate synthesis).”

In catabolism, metabolic pathways are organised such that energy is released slowly in discrete quanta of energy, which is captured by the synthesis of high-energy phosphate bonds, mainly in the form of ATP. Glycolysis relies on NAD+ to accept electrons from glucose forming NADH and H+. NAD+ can be re-oxidised from NADH in order to ensure a cyclic effect of glycolysis in all cells. This can be accomplished under both aerobic and anaerobic conditions. However, in the presence of oxygen, NADH passes its electrons into the ETC, allowing the complete oxidation of glucose.

Glycolysis refers to the intracellular breakdown of glucose into pyruvic acid and ATP. Glycolysis takes place in the cytoplasm... The citric acid cycle, also known as the Krebs cycle, is the next step in intracellular glucose metabolism. It takes place in the mitochondria and is initiated by acetyl coenzyme A (acetyl CoA)... While the citric acid cycle does not itself produce much ATP, the NADH and FADH2 molecules act as electron carriers that shuttle into the electron transport chain for oxidative phosphorylation and high-energy production.

We can think of catabolism as occurring in three stages (Figure \(\PageIndex{1}\)). In stage I, carbohydrates, fats, and proteins are broken down into their individual monomer units: carbohydrates into simple sugars, fats into fatty acids and glycerol, and proteins into amino acids. One part of stage I of catabolism is the breakdown of food molecules by hydrolysis reactions into the individual monomer units—which occurs in the mouth, stomach, and small intestine—and is referred to as digestion.

Understand the four stages of metabolism: (1) Digestion, (2) Acetyl-CoA production, (3) Citric acid cycle, and (4) Electron transport chain and oxidative phosphorylation.

The breakdown of glucose begins with glycolysis, which is a ten-step metabolic pathway yielding two ATP per glucose molecule; glycolysis takes place in the cytosol and does not require oxygen. In addition to ATP, the end-products of glycolysis include two three-carbon molecules, called pyruvate. Pyruvate can either be shuttled to the citric acid cycle to make more ATP... Acetyl-CoA, a two-carbon molecule common to glucose, lipid, and protein metabolism enters the second stage of energy metabolism, the citric acid cycle... Stage 3. Electron Transport Chain and ATP synthesis.

The stages of cellular respiration include glycolysis, pyruvate oxidation, the citric acid or Krebs cycle, and oxidative phosphorylation.

So we now see, we get four from just what we've done so far. Glycolysis, the preparatory stage and the Krebs or citric acid cycle. And then eventually, these ...

All of the catabolic pathways for carbohydrates, proteins, and lipids eventually connect into glycolysis and the citric acid cycle pathways... The breakdown and synthesis of carbohydrates, proteins, and lipids connect with the pathways of glucose catabolism.

Catabolism can be broken down into 3 main stages. Stage 1 – Stage of Digestion: The large organic molecules like proteins, lipids and polysaccharides are digested into their smaller components outside cells. Stage 2 – Release of energy: Once broken down these molecules are taken up by cells and converted to yet smaller molecules, usually acetyl coenzyme A (acetyl-CoA), which releases some energy. Stage 3 - The acetyl group on the CoA is oxidised to water and carbon dioxide in the citric acid cycle and electron transport chain.

Гликолиз — это катаболический путь обмена веществ в цитоплазме; он протекает почти во всех организмах... В аэробных условиях молекула глюкозы деградирует до пирувата, после чего следует цикл Кребса в митохондриях и окислительное фосфорилирование.

Metabolism comprises of two major parts: anabolism (building up, also called biosynthesis) and catabolism (breaking down). ATP production – in the citric acid cycle (also called the Kreb’s or TCA cycle), CoA’s acetyl group is oxidized to water and carbon dioxide. The energy released from this is stored in ATP by reduction of the coenzyme adenine dinucleotide (NAD+) into NADH in the electron transport chain. This process is called oxidative phosphorylation and releases carbon dioxide as a waste product.

В какой части клетки происходит гликолиз? ... D. Цитоплазма. Гликолиз - это процесс расщепления глюкозы до пирувата в цитоплазме, первый этап клеточного дыхания.

Гликолиз упоминается как ключевой метаболический путь в цитоплазме, но статья фокусируется на его роли в макрофагах, не детализируя полную цепь катabolic metabolism.

This diagram illustrates the tricarboxylic acid (TCA) cycle, showing the sequence of reactions that oxidize acetyl‑CoA to CO₂ while generating NADH, FADH₂, and GTP (or ATP).

The content in this category covers the principles of bioenergetics and fuel molecule catabolism. Details of oxidative phosphorylation including the role of the electron transport chain in generating a proton gradient across the inner mitochondrial membrane and the role of ATP synthase in generating ATP.

For ATP to be produced by oxidative phosphorylation, electrons are needed. These come from electron carriers produced by the TCA cycle.

Aerobic metabolism consists of three phases: breakdown of biopolymers in the digestive tract to monomers. In this phase, there are no oxidative reactions, and no macroergic compounds are synthesized. It is associated with processes in which ATP molecules are synthesized, namely oxidative phosphorylation.

Гликолиз протекает в клеточной цитоплазме, причем первые девять реакций (превращение глюкозы в пируват) образуют первый этап клеточного дыхания.

Процесс расщепления глюкозы, называемый гликолизом, происходит в цитоплазме клеток млекопитающих... расщепляется до пирувата, конечного продукта гликолиза в аэробных условиях.

In standard biology textbooks, the main stages of glucose catabolism are glycolysis (cytosol, glucose to pyruvate), pyruvate oxidation to acetyl-CoA, citric acid cycle (mitochondria, acetyl-CoA oxidation), and oxidative phosphorylation via the electron transport chain (inner mitochondrial membrane, ATP synthesis). Digestion is a separate physiological process outside cells, breaking down food polymers into monomers for absorption, not a stage of cellular catabolic metabolism.

In the first stage, food taken by the organism is crushed, transported, and broken down or built up to certain transport molecules and monomers using enzymes and acids in the body. This is called extracellular breakdown. The second stage is the breakdown of monomers and other small 'nutrient' molecules, releasing a small amount of energy. The third stage involves complete breakdown of substances to water and CO2 and synthesis of a large amount of ATP. The second and third stages are intracellular digestion.

Гликолиз происходит в цитоплазме, а не в митохондриях... Гликолиз — многоступенчатое расщепление молекулы глюкозы до двух молекул пировиноградной кислоты (пируват).

Гликолиз происходит в цитоплазме прокариотических или эукариотических клеток.

Learn the 13 major metabolic pathways... Pathways include Glycolysis, Pyruvate Dehydrogenase Complex (PDH), Citric Acid (Krebs) Cycle, Electron Transport Chain... aerobic respiration so the process of glycolysis through the PD through the citric acid cycle and through the electron transport chain to produce ATP from glucose.

Central catabolic chain providing energy in all cells. During this stage, two interconnected processes occur - biological oxidation and phosphorylation of ADP. The four hydrogen atoms released during biological oxidation bind to NAD+ and reduce it (NADH), and the energy released is used for the synthesis of 4 ATP molecules.

The Krebs cycle, also known as the citric acid cycle, is a key stage in metabolism that converts acetyl-CoA into CO₂ and electron carriers.

The body's need for energy is satisfied through digestion, during which molecules from unprocessed energy (food) are broken down. The breakdown of food molecules is a complex process that provides the body with nutritional building elements necessary for constructing more desirable molecules.

Anaerobic catabolism occurs without the presence of oxygen. The main process is glycolysis, followed by fermentation.

Metabolic processes. Processes are oxidative, proceed with release of H. Processes are reductive, H donor.

Гликолиз происходит в цитоплазме (цитозоле), где глюкоза расщепляется с образованием NADH; в отсутствие кислорода процесс останавливается без дальнейших стадий.

Catabolism also includes the breakdown of stored glycogen and fats for energy. The body breaks down proteins to amino acids, which can be converted to glucose via gluconeogenesis to fuel the body's energy needs.

Catabolism is a metabolic process during which the organism breaks down complex and larger structures to create simpler and smaller ones. For example, when the body breaks down muscle tissues, it breaks down the structure and extracts the smaller elements, which are proteins, to amino acids, which are the simplest structure.