2. Operon A group of genes that operate together is known as an operon. Because these genes must be expressed in order for the bacterium to be able to use the sugar lactose as food, they are called the lacoperon.
3. Operator The (O) region of a chromosome in an operon to which the repressor binds when the operon is “turned off”. When the lac repressor binds to the (O) region, RNA polymerase is prevented from beginning the process of transcription.
4. Differentiation This is the process of development in which cells become specialized in structure and function. They don’t just divide during embryonic development, they also become specialized.
5. Hox Gene A series of genes, known as the hox genes, control the differentiation of cells and tissues in the embryo. Mutations can effect these genes, which can change the development of organs and other body parts.
6. How are lac genes turned off and on? The lac genes in E. coli are turned off by repressors and turned on by the presence of lactose. Lactose causes the repressor to be released from the operate (O) region.
7. How are most eukaryotic genes controlled? Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lacoperon. Operons are generally not found in eukaryotes. Many eukaryotic genes include a sequence called the TATA box that may help RNA polymerase.
