BI0157 Biochemistry Labs

Lab 3: Design-it-yourself Glycolysis

Test your understanding of the chemistry involved in glycolysis at the Design-it-yourself glycolysis site produced by Jon Maber at the University of Leeds. If that link is not working, then try this mirror site.

INTRODUCTION
The process of glucose catabolism, glycolysis, involves a reaction sequence that is the single most ubiquitous pathway in all energy metabolism. Glycolysis occurs in almost every living cell, in aerobically as well as anaerobically living organisms. It is generally regarded as a primitive process that evolved early in biological history. It occurs in the cytosol, rather than in a special compartment. The essence of the process is the splitting of a six-carbon molecule, glucose, to yield two three-carbon molecules, one of which, glyceraldehyde-3-phosphate, is the only oxidisable molecule in the whole pathway. Subsequent to the cleavage, two ATP-generating steps occur. These represent the energy payoff of glycolysis, and are the only ATP-yielding reactions in glucose catabolism under anaerobic conditions. Note that these ATP molecules are obtained by the direct transfer of a phosphoryl (P_i) group from a high-energy compound to ADP. This process is called substrate-level phosphorylation.

In the presence of oxygen as electron acceptor (aerobic conditions), however, the glucose molecule can be completely oxidised to CO₂. A large part of the extra electrons thus obtained are used in the process of oxidative phosphorylation. In this process, which takes place in the mitochondrial membrane, the generation of a proton motive force across the membrane is coupled to ATP-production. This process, oxidative phosphorylation, differs from the earlier mentioned substrate-level phosphorylation. This metabolic process is not studied in this lab exercise.

No lab report is required for this computer lab. Instead, you will have to answer a list of questions, which will be given to you at the beginning of the lab.

Reading material: Horton, chapters 8 & 11

Lectures:
Carbohydrates, glycolysis

Links:
Design-it-yourself glycolysis
Another glycolysis tutorial

Lab index

[1 - basic lab techniques] [1] [2] [4]