1.  For transcription to begin the gene needs to be stimulated by transciptional factors. These move from the cytoplasm into the nucleus.  Each transcriptional factor has a site that binds to a specific region of DNA  When it binds it stimulates transcription  mRNA is then produced and translation into a polypeptide occurs.  When the gene is not being expressed the site that the transcriptional factor binds to is blocked by an inhibitor molecule.  The inhibitor molecule prevents the transcriptional factors from binding and thus prevents transcription

2.  One way which has been researched but you do not have to necessarily know about is the Lac Operon

3.  The example you have to know about is how the effect oestrogen has on transcription.  Using figure 1 from page 214 and the information on page 240 produce a flow diagram of how oestrogen effect gene transcription.

4.  http://www.nature.com/focus/rnai/animations/inde x.html http://www.nature.com/focus/rnai/animations/inde x.html  Watch the following animation and make notes, we are going to watch it twice so do not panic!  Read through the two articles about how Andrew Z. Fire and Craig C. Mello were award the Nobel prize for their work in discovering si-RNA  Task using you notes and the articles write a 5 minute speech explaining what si-RNA is, how it works and its significance to medicine.

5.  Complete the application questions from page 242 – 243  Start working on the exam style questions on page 244 – 245 these have to be completed for homework.