It depends on the replication configuration. The two Replication Formats are Statement-based Replication and Row-Based Replication.
If the Statement-Based Replication is used, the master writes SQL statements to the binary log and the SQL statements are executed on the slave.
In the case of Row-Based Replcation, the master writes events to the binary log that indicate how individual tables rows are changed. These events are then copied to the slave.
Another format is Mixed-Based Replication. MySQL replication can also be configured to use a mix of both Statement and Row-Based logging. Statement-based log is used by default, but depending on certain statements, the log is automatically changed to row-based.
Refer to binlog_format, to configure the logging format and for more information.