Which molecule is broken down during glycolysis?

Which molecule is broken down during glycolysis?

• A. Fructose
• B. Starch
• C. Glucose
• D. Lactose

Answer: (C)

Glycolysis begins with glucose, a six-carbon sugar, which is broken down to two three-carbon molecules while producing ATP and NADH. The other options aren’t the molecule that glycolysis directly uses: fructose is a different sugar that can feed into glycolysis after conversion; starch is a large polymer that must be broken down into glucose first; lactose is a disaccharide that must be split into glucose and galactose before glycolysis. So the molecule directly broken down in glycolysis is glucose.

Glycolysis begins with glucose, a six-carbon sugar, which is broken down to two three-carbon molecules while producing ATP and NADH. The other options aren’t the molecule that glycolysis directly uses: fructose is a different sugar that can feed into glycolysis after conversion; starch is a large polymer that must be broken down into glucose first; lactose is a disaccharide that must be split into glucose and galactose before glycolysis. So the molecule directly broken down in glycolysis is glucose.