| A | B |
|---|
| Promoter | A site where the transcription enzyme, RNA polymerase, attaches and initiates transcription |
| Operon | A cluster of genes with related functions, along with a promoter and an operator |
| Repressor | A molecule that can turn off transcription; binds to the operator, blocks RNA polymerase |
| Regulatory Gene | Located outside the operon; codes for the repressor molecules |
| Histones | A small protein that plays a crucial role in DNA packing |
| Nucleosome | A.k.a. “bead,” consisting of DNA wound around a protein core of 8 histone molecules |
| Barr body | The inactive X in each cell of a female; exists in a compact/condensed form |
| Transcription factors | Required by eukaryotic RNA polymerase to function; proteins that assist transcription |
| Enhancers | DNA sequences to which activator proteins bind to initiate eukaryotic transcription |
| microRNA (miRNA) | small, single-stranded RNA molecules bind to complementary mRNA molecules only |
| RNA interference (RNAi) | Uses miRNA mechanism to artificially control gene expression (p.215) |
| Homeotic gene | A master control gene that regulates other genes; determines anatomy |
| DNA microarrays | Test for which genes are active (transcribed); uses cDNA and fluorescent nucleotides |
| Signal transduction pathway | What occurs between a signal on a cell’s surface and the internal cell response (many steps) |
| Oncogene | A gene that, when present in a single copy in a cell, can cause cancer |
| Proto-oncogene | A normal gene that has the potential to become an oncogene (e.g., via mutation) |
| Embryonic stem cells | Give rise to all different kinds of specialized cells of the body; totally unlimited |
| Adult stem cells | give rise to many (but not all) cell types in an organism |
| Reproductive cloning | The type of cloning that results in birth of a new organism |
| Therapeutic cloning | The goal is to produce embryonic stem cells for therapeutic uses |
| Nuclear transplantation | How “Dolly” was cloned; see page 222 for details |
