5 WK 5 Carbon Cycling_ CR 24-25 Andrew Nguyen_ Cellular Respiration

What is glycolysis?

Glycolysis is a central metabolic pathway that breaks down glucose (a six-carbon sugar) into pyruvate (a three-carbon compound) through a series of ten enzymatic reactions. This process occurs in the cytoplasm of cells and generates energy-rich molecules: 2 ATP (adenosine triphosphate) are produced while also reducing NAD+ (nicotinamide adenine dinucleotide) to NADH. Glycolysis is the first step in the cellular respiration process, which can lead to further energy production under aerobic or anaerobic conditions.

What are the first steps in glycolysis?

The first steps of glycolysis involve the phosphorylation of glucose to form glucose-6-phosphate. This is achieved through the action of the enzyme hexokinase, and it requires the consumption of 2 ATP molecules. This phosphorylation is crucial for 'tr trapping' glucose within the cell and initiating its metabolic breakdown for energy production.

What happens during the energy investment phase of glycolysis?

The energy investment phase consists of the first five reactions of glycolysis, where ATP is utilized to convert glucose into energy-utilizing intermediates, such as fructose-1,6-bisphosphate. In this phase, glucose experiences modifications that prepare it for subsequent cleavage into smaller molecules, which is essential for the subsequent processes leading to energy extraction.

What occurs during the energy payoff phase of glycolysis?

The energy payoff phase comprises the last five reactions of glycolysis, resulting in the generation of ATP through substrate-level phosphorylation. Additionally, NAD+ is reduced to form NADH, a key energy carrier. This phase concludes with the formation of pyruvate, which can then enter further metabolic pathways such as the Krebs cycle if oxygen is present (aerobic respiration) or undergo fermentation (anaerobic respiration).