Summary
A ten-step pathway in the cytoplasm that splits glucose into two pyruvate, yielding net 2 ATP and 2 NADH.
In depth
The investment phase uses 2 ATP (hexokinase, phosphofructokinase), the payoff phase makes 4 ATP and 2 NADH, giving net 2 ATP, 2 NADH and 2 pyruvate. Phosphofructokinase is the key control point. Occurs without oxygen and is found in nearly all organisms, suggesting an ancient origin.
Glycolysis converts one 6-carbon glucose into two 3-carbon pyruvate. It is regulated by phosphofructokinase, hexokinase and pyruvate kinase. It occurs in cytoplasm of all cells.
Example: red blood cells rely wholly on it.
Glycolysis ("sugar splitting") is a ten-step pathway in the cytoplasm that converts one 6-carbon glucose into two 3-carbon pyruvate molecules. An investment phase uses 2 ATP to phosphorylate and split the sugar, and a payoff phase makes 4 ATP and 2 NADH, for net 2 ATP.
It needs no oxygen, is found in nearly all organisms, and is probably one of the oldest pathways. Key regulated enzymes include hexokinase and phosphofructokinase (PFK), which is inhibited by ATP and citrate and activated by AMP.
Example: red blood cells, which lack mitochondria, rely on it entirely.
Frequently asked questions
What is Glycolysis?
A ten-step pathway in the cytoplasm that splits glucose into two pyruvate, yielding net 2 ATP and 2 NADH.
Which area of biology covers Glycolysis, and how advanced is it?
Glycolysis is one of the 53 topics in Metabolism & Bioenergetics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Glucose as Fuel, Gluconeogenesis, Pentose Phosphate Pathway.
Why does Glycolysis matter?
It provides fast ATP and precursors for other pathways.
Can you give an example of Glycolysis?
Cancer cells and red blood cells rely heavily on glycolysis.
What should I learn before Glycolysis?
Work through the Beginner topics in Metabolism & Bioenergetics first, such as Metabolism, Anabolism and Catabolism, ATP, then return to Glycolysis. Intermediate topics assume the Beginner vocabulary.
What topics are related to Glycolysis?
The closest topics to Glycolysis are Glucose as Fuel, Gluconeogenesis, Pentose Phosphate Pathway, Aerobic and Anaerobic Respiration. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Glycolysis?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Glycolysis. To practise the whole of Metabolism & Bioenergetics, use the Metabolism & Bioenergetics quiz.
How is Glycolysis different from Glucose as Fuel?
Glycolysis: A ten-step pathway in the cytoplasm that splits glucose into two pyruvate, yielding net 2 ATP and 2 NADH. Glucose as Fuel: The main sugar broken down to supply cellular energy. Read both side by side and note what each one explains.
How should I study Glycolysis step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Glucose as Fuel and explain the difference aloud. Finally, take the Metabolism & Bioenergetics quiz and come back to this page for any question you miss.