Gene Regulation Section 12ndash;5.ppt

Gene Regulation Section 12–5 This section explains how some genes in prokaryotes and eukaryotes arecontrolled. Gene Structure Gene Regulation: Where does RNA polymerase bind? It binds to the promoter. Gene Regulation: Is the following sentence true or false? The actions of DNA-binding proteins help to determine whether a gene is turned on or turned off. Gene Regulation: What is an operon? It is a group of genes that is operated together. Gene Regulation: What is the function of the genes in the lac operon? They must be expressed for E. coli to use lactose as a food. Gene Regulation: Circle the letter of each sentence that is true about lactose. To use lactose for food, E. coli must take lactose across its cell membrane. The bond between glucose and galactose must be broken in order for E. coli to uselactose for food. Gene Regulation: Circle the letter of the number of genes in the lac operon found in E. coli. 1 2 3 4 Gene Regulation: What turns the lac operon off and on? The lac genes are turned off by repressors and turned on by the presence of lactose. Gene Regulation: How does the repressor protein prevent transcription? It prevents RNA polymerase from binding to the operator. Gene Regulation: How does lactose cause the lac operon to turn on? Lactose molecules bind to the repressor protein, causing it to change shape so that the repressor releases the operator. This allows RNA polymerase to bind to the promoter and transcribe the genes of the operon. Gene Regulation: Circle the letter of each sentence that is true about gene regulation in prokaryotic genes. b. Many other genes are regulated by repressor proteins.c. Some genes are regulated by proteins that enhance the rate of transcription. Eukaryotic Gene Regulation  Is the following sentence true or false?  Operons are frequently found in eukaryotes. False Eukaryotic Gene Regulation: How are eukaryotic genes usually controlled? Most are controlled individual