Scientists investigated the function of a eukaryotic cell protein called Cdc6. This protein is involved in recruiting and loading the helicase enzyme required to initiate DNA replication.
The scientists treated cultures of cells in four different ways:
They then determined the percentage of cells in each culture in which DNA replication was occurring. Their results are shown in the table below:
| Cell treatment | Percentage of cells where DNA was replicating |
|---|---|
| W (Control) | 88%88\%88% |
| X (Antibody to Cdc6) | 12%12\%12% |
| Y (siRNA against Cdc6) | 9%9\%9% |
| Z (siRNA + exogenous Cdc6) | 87%87\%87% |
Suggest explanations for the results of Treatment X, Treatment Y, and Treatment Z.
21 exam-style questions on AQA A Level Biology Gene expression is controlled by a number of features (A-level only), covering Most of a cell's DNA is not translated (A-level only), Regulation of transcription and translation (A-level only), and Gene expression and cancer (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.