gen-define-glycolysis-and-give-one-short-worked-example-cacb

Define glycolysis and give one short worked example.

# Glycolysis **Definition:** Glycolysis is the metabolic pathway that breaks down one molecule of glucose (a 6-carbon sugar) into two molecules of pyruvate (3-carbon compounds), producing a net gain of 2 ATP and 2 NADH. This process occurs in the cytoplasm and does not require oxygen. ## Worked Example **Question:** Calculate the net ATP yield from glycolysis when one glucose molecule is metabolized. **Solution:** Starting with: 1 glucose molecule **ATP Investment Phase (energy input):** - Step 1: Glucose → Glucose-6-phosphate uses **1 ATP** - Step 3: Fructose-6-phosphate → Fructose-1,6-bisphosphate uses **1 ATP** - **Total ATP consumed: 2 ATP** **ATP Payoff Phase (energy output):** - Step 7: 2 × (1,3-bisphosphoglycerate → 3-phosphoglycerate) produces **2 ATP** - Step 10: 2 × (Phosphoenolpyruvate → Pyruvate) produces **2 ATP** - **Total ATP produced: 4 ATP** **Net ATP yield:** ``` Net ATP = ATP produced - ATP consumed Net ATP = 4 - 2 = 2 ATP ``` **Answer:** Glycolysis produces a net gain of **2 ATP** per glucose molecule, plus 2 NADH and 2 pyruvate.