A node is a logical grouping of managed servers.A node usually corresponds to a logical or physical computer system with a distinct IP host address. Where as a Cell is logical grouping of multiple nodes.
Cell profile : Use the cell profile to make applications available to the Internet or to an intranet under the management of the deployment manager.
Creation of a cell profile generates a deployment manager profile and a federated node profile in one iteration through the Profile Management tool. The result is a fully functional cell on a given system.

Important Terms in WAS
Cell : Represents a logical grouping of multiple nodes for administrative purposes.
Node : Represents a physical system running one or more WebSphere servers.
Server : Represents an instance of a Java™ virtual machine (JVM).
Cluster : Represents a logical grouping of multiple application servers within a cell for administration, application deployment, load balancing, and failover purposes.
Federation :The process of joining a stand-alone WebSphere node to a WebSphere cell.
Picture to visualize the things :
References : [1][2][3][4]