What is a coupled reaction?

What is a coupled reaction? Describe oxidation-reduction reactions and draw an example. Label both the oxidizing and reducing agents. Which molecule is oxidized? Which is reduced? Can you think of a mnemonic to describe oxidation-reduction reactions? >What is an enzyme? How can you recognize an enzyme? >Enzymes are said to be "picky" molecules. In what three ways are enzymes "picky?" >What are coenzymes? What types of organic compounds commonly function as coenzymes? > Carbohydrates. Discuss functions & basic chemical composition: