Possible Explanation

Molecular Machines as Functional Systems

Molecular Machines and Integrated Biological Systems • Molecular Machinery

Living cells contain organized molecular assemblies that perform functions resembling motors, transport systems, assembly lines, information processors, and quality-control machinery.

The Explanation

The term "molecular machine" is not merely an analogy used by Intelligent Design advocates. Molecular biologists routinely describe large protein assemblies in mechanical and functional terms because their components interact in organized ways to accomplish particular tasks.

ATP synthase rotates while coupling an ion gradient to ATP production. Motor proteins transport cargo through cells. Ribosomes coordinate the translation of genetic information into proteins. Other complexes fold, inspect, transport, and degrade cellular components.

Supporting Evidence

The evidence examined here includes ATP synthase, kinesin and dynein, the ribosome, molecular chaperones, the proteasome, and the bacterial flagellum. These systems differ greatly in structure and function, but each depends upon coordinated interactions among multiple molecular components.

Modern cell biology therefore presents the cell not simply as a collection of independent chemical reactions but as an organized system containing interacting molecular assemblies.

Limitations

Calling something a machine does not establish that it was intelligently designed. Machine terminology describes organization and function. It does not by itself identify the origin of that organization.

Questions That Remain

What features of molecular machinery can be explained by chemistry and evolutionary history, and which features, if any, require an additional explanation?

Intelligent Design Response

Intelligent Design should not infer design merely from the word "machine." The design question concerns the origin of the functional organization, coordination, and information required to produce and integrate these molecular systems.

Research Sources

Alberts — The Cell as a Collection of Protein Machines

Bruce Alberts • Cell • 1998

Provides a broad scientific basis for describing cellular processes as the work of interacting protein machines.

Alberts describes major cellular processes as being carried out by organized assemblies of proteins and emphasizes that these molecular machines interact within larger cellular systems.

Scientific Foundation

Noji et al. — Direct Observation of F1-ATPase Rotation

Hiroyuki Noji; Ryohei Yasuda; Masasuke Yoshida; Kazuhiko Kinosita Jr. • Nature • 1997

Provides direct experimental evidence of rotary motion in F1-ATPase.

Direct observation of ATPase rotation provides a particularly clear example of why mechanical terminology is useful when describing some molecular systems.

Experimental Evidence

Ramakrishnan — Ribosome Structure and the Mechanism of Translation

Venkatraman Ramakrishnan • Cell • 2002

Provides structural and mechanistic context for understanding the ribosome as a complex molecular machine.

The ribosome demonstrates that molecular machinery includes not only movement and energy conversion but also coordinated processing of genetic information.

Information Processing