The following diagram outlines the events that occur as a result of a particular signalling molecule - VCE - SSCE Biology - Question 24 - 2008 - Paper 1

To determine the correct answer, we need to analyze each stage in the provided diagram that represents the process of signal transduction.

1. Stage 1: The binding of a signalling molecule to the cell membrane initiates the process. This is crucial as it starts the transduction pathway.

2. Stage 2: Second messengers are generated, which relay the signal within the cell. This indicates a critical part of signal amplification and processing.

3. Stage 3: Changes in gene expression happen, leading to the synthesis of new proteins based on the received signal. This step is significant as it reflects how external signals can modify cellular function.

4. Stage 4: The newly synthesized proteins are processed in the Golgi apparatus and prepared for secretion from the cell, finalizing the response to the signalling molecule.

Based on this analysis, the entire process of signal transduction is fully represented in Stage 1, making the correct answer A. 1.