Glycolysis

Introduction

• Glycolysis is the initial step of cellular respiration, where glucose is broken down into two molecules of pyruvate.
• This process occurs in the cytoplasm of cells and can take place in the absence of oxygen, making it anaerobic.

Key Stages of Glycolysis

1. Glucose Activation

• Glucose is phosphorylated, requiring the input of two ATP molecules.
• This step activates glucose and prepares it for further breakdown.

2. Glucose Splitting

• The activated glucose molecule is split into two molecules of glyceraldehyde-3-phosphate (G3P).
• Each G3P molecule is then converted into pyruvate through a series of reactions.

3. Energy Production

• During the conversion of G3P to pyruvate, energy is generated.
• NADH (a molecule that carries high-energy electrons) is also produced.

Energy Investment and Gain

• Glycolysis begins with an energy investment stage (ATP is used to activate glucose and intermediates).
• However, more ATP molecules are generated in subsequent reactions, resulting in a net gain of ATP.

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Biology

Glycolysis

Role of Dehydrogenase Enzymes

• Dehydrogenase enzymes are involved in glycolysis and the citric acid cycle.
• They remove hydrogen ions (H+) and electrons (e-) from intermediates.
• These hydrogen ions and electrons are transferred to the coenzyme NAD, forming NADH.
• NADH carries high-energy electrons to the electron transport chain in later stages of cellular respiration.

Summary