Skip to content
MathsGenie logo
Open app

Course home

  1. A Level
  3. Biology AQA
  5. Question bank

Gene expression is controlled by a number of features (A-level only)

EasyMediumHard
12345678910111213141516
Question 8

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:

  • Treatment W: Control cells, untreated
  • Treatment X: Added a specific monoclonal antibody that binds to Cdc6
  • Treatment Y: Added small interfering RNA (siRNA) that prevents translation of Cdc6 mRNA
  • Treatment Z: Added siRNA that prevents translation of Cdc6 mRNA and added exogenous, active Cdc6 protein

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 treatmentPercentage 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.

[6]

Gene expression is controlled by a number of features (A-level only) Questions

  1. A Level
  2. /Biology
  3. /Gene expression is controlled by a number of features (A-level only)