The Top Ten COOLEST “words” (in Eukaryotic Gene Expression) And now…. The Top Ten COOLEST “words” (in Eukaryotic Gene Expression) 10. Retrotransposons - genetic elements that can amplify themselves in a genome and are ubiquitous components of the DNA of many eukaryotic organisms. They copy themselves to RNA and then, via reverse transcriptase, back to DNA. 9. Immunoglobulin- (also known as antibodies) proteins that are found in blood or other bodily fluids of vertebrates, and are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses. Coded for by permanent rearrangement of DNA in B lymphocytes!!! 8. Helix-Turn-Helix Motif - One type of Transcription Factor Binding Domain (TFBD) which is part of the factor’s 3-dimensional structure. This one is is composed of two α helices joined by a short strand of amino acids. 7. Zinc-Finger Motif - another type of TFBD, consists of two antiparallel β sheets, an α helix, all wrapped around a zinc atom.

The Top Ten COOLEST “words” (in Eukaryotic Gene Expression) 6. Leucine Zipper Motif: A third type of TFBD: 2 α-helices with regularly spaced leucines wrapping around each other. 5. Ubiquitin: Cytosolic enzymes which attach to molecules and mark it for destruction. 4. Proteasomes: Huge protein complexes that recognize the ubiquitin tagged molecules, engulfs them in their barrel-like structures and chops them up. D:\bc_campbell_biology 3. Ras-Oncogenes: Actually begin as “Proto-oncogenes” which code for relays in a cell’s normal response to growth factors to stimulate cell division. When it mutates into an oncogene, it codes for an over active relay which causes uncontrolled cell growth …..CANCER!!

The Top Ten COOLEST “words” (in Eukaryotic Gene Expression) 2. Apoptosis: Programmed cell death in embryonic development certain genes code for destructive enzymes at critical stages of gestation. And the number one word in Eukaryotic gene expression… 1. Sonic-Hedgehog factor: A protein growth factor that gives positional information to growing tissues that are part of the posterior side of a “bud”….. …..now wasn’t that fun!?!