Tanner Young Al Young 2006-11-30T05:04:21Z 2006-11-30T00:27:00Z 2007-07-11T22:33:00Z UCLA MC EMC 11.5703 11688 15180 120 72 False False Eukaryotic Gene Regulation Tanner Young Mechanism On/Off Volume How Does it Function? A2 Activators Enhancers and Chemical Initiation Presence of other transcription factors and Control Elements The Activator is a special transcirption factor that binds to an enhancer. This complex allows other transciprtion factors and an RNA polymerase to attach to make pre-mRNA. Transcription Factors Chemical Initiation and Attachment to a Transcription Complex Control Elements It binds to a specific sequence of DNA and a complex allows for pre-mRNA synthesis. Splicing RNA Processing How many interons and other non-coding strands are in the RNA. Splicosomes form around the pre-mRNA. The complexes in turn break the pre-MRA into the form that it will be utilized by the cell. Steroids Presence in a cell Amount secreted It binds to a receptor protein in the cytoplasm or nucleus. It then acts as a transcription factor. Ribosome Presence of mRNA Amount of mRNA It binds to an mRNA molecule, and it translates the mRNA into a polypeptide chain. Enhancers Presence of Activators How much the DNA bends to initiate transcription of DNA. Enhancers are DNA sequences that bind to activators. These activators in turn position the transciption complex prior to transcription. Degredation Time How quickly a molecule (mRNA or a protein) deteriorates by chemical reaction. What molecular groups surround the molecule. (The more groups the longer the degredation time.) A molecule-either mRNA or a protein-will break down by enzyme catalisys in a certain period of time. For example a hemoglobin mRNA can last indefinitely because of its moelecular structure, but another can only last a few hours. Acytlation Chemical Initiation How removed the DNA needs to be from the histone. An enzyme attaches acytl groups to histones to break the DNA away temporarlily for transcription or DNA repair. Phosphorylation Chemical Stimulation How long the phosphate group remains attached to the protein. A phosphate group attaches to a transcription molecule making it useless until the phsophate is removed. This allows the cell to compensate for too much transcription. Methylation Chemical Stimuli How many genes need to be deactivated. Methyl groups are attached to the DNA molecule rendering transcription impossible. Mutation Random DNA Synthesis Errors How well the cell repairs its own DNA. It causes changes in a gene, and this leads to a change in either the gene's ability to be transcirbed or its ability to be processed properly. Gene Methylation Transcrption factor concentration It codes for pre-mRNA. It is transcirbed by the transcription complex. Transposons Presence of Proteins Amount of Proteins They move around the genome in the same that prokaryotes do, except their movement is based on RNA not DNA. The cell uses reverse transcriptase to intorduce the DNA into the proper genome position. Amplification Presence of Mutliple Copies of a Gene How many are present The amplified gene will make many more copies of itself than it would normally. This is why trisomy is so dangerous to humans. It leads to a disproportionate amount of proteins from a chromosome. -3 0 3 5 7 False False