Coordination within paragraphs

Expressing coordinate ideas in a parallel structure also applies within paragraphs. Look at this example, consisting of a sentence which expresses the topic of the paragraph, followed by three coordinate ideas:

"The lock-and-key hypothesis was first formulated in 1897 by Emil Fischer, the noted German chemist. He used it to explain the specificity of interactions between enzymes and their substrates. Pioneering immunologist Paul Ehrlich extended it in 1900 to account for the highly specific reactions of the immune system, and researcher Frank Lillie employed it in 1914 to describe recognition between sperm and eggs."

The topic is the lock-and-key hypothesis, expressed in a suitable topic statement.

Topic statement: "The lock-and-key hypothesis was first formulated in 1897 by Emil Fischer, the noted German chemist."

Then follows a description of the three ways this hypothesis has been used. These are coordinate ideas - note how they are skillfully expressed in parallel gramatical structure:

Subject/Verb/Object

• He used it...
• Pioneering immunologist Paul Ehrlich extended it...
• Researcher Frank Lillie employed it...

Verb/Time Modifier

• extended it in 1900...
• employed it in 1914...

Infinitive Clause Complement

• to explain the specificity of...
• to account for the highly specific reactions of...
• to describe recognition between...

Again, potentially complex ideas have been made easier to grasp through the application of Requirement 1.