Unit 8
Metabolic Pathways

Overview

There are virtually no biochemical reactions in a cell that are not connected to other reactions. This statement makes sense if you realize that reaction A will consume certain biomolecules (reactants), and produce other biomolecules (products). Unless there is a process to produce the reactants for reaction A, the reaction will not occur. Unless there is another process to consume the products of reaction A, these products will accumulate and overload the system. The complex sequences of chemical processes that produce products and consume reactants, are called “metabolic pathways,” and form the subject of the single lesson in this unit.

Objectives

After completing this unit, you should be able to

  1. explain the meaning of the term “metabolic pathway.”
  2. list the principle characteristics of metabolic pathways, and explain the purpose of each of the two major types of pathways.
  3. identify the types of chemical reactions that are important in biochemistry.

Glossary

elimination reaction reaction in which a molecule decomposes into two molecules of unequal size
metabolic pathway tightly regulated, interconnected set of biochemical reactions in which some chemicals (nutrients) are used up and other chemicals are produced (e.g., glucose → ATP)
oxidation loss of one or a pair of electrons
redox reaction reaction in which electrons are transferred from one molecule to another
reduction gain of one or a pair of electrons
Top