Review 7 Control of Gene Expression 1. All organim’s ____________ encodes all of the RNA and protein molecules that are needed to make its cell. Nealy all the cells of a multicellular organism contain the same ___________. 2. _____________ is a complex process by which cells selectively direct the synthesis of the many thousands of proteins and RNAs encoded in their genome. Cell differentiation is achieved by changes in __________________. - Fill in the blanks in the following statements and place the types of control listed below at the appropriate places on the diagram 3. _______________ control determines when and how often a given gene is transcribed. 4. _______________ control determines how the primary RNA transcripts is spliced or otherwise processed. 5. _______________ control determines which completed mRNAs in the cell nucleus exported to the cytoplasm. 6. _______________ control determines which mRNAs in the cytoplasm are transcribed by ribosomes. 7. _______________ control selectively destabilizes certain mRNA molecules in the cytoplasm. 8. _______________ control activates, inactivates, or compartmentalizes specific protein molecules after they have been made. 9. In principle, gene expression can be controlled at any of the steps between a gene and its ultimate functional product. For the majority of genes, however, the __________ is the most important point of control. Because this control point can ensure that no unnecessary intermediates are synthesized. 10. The genes of a bacterial ___________ are transcribed into a single mRNA. Many bacterial promoters contain a region known as an _____________, to which a specific transcription regulator binds. 11. How are most eukaryotic transcription regulators able to affect transcription when their binding sites are far from the promoter?12. Label the following structures in Figure. A. activator protein B. RNA polymerase C. general transcription factors D. Mediator 13. From the sequencing of the human genome, we believe that there are approximately 21,000 protein-coding genes in the genome, of which 1500–3000 are transcription factors. If every gene has a tissue-specific and signal-dependent transcription pattern, how can such a small number of transcriptional regulatory proteins generate a much larger set of transcriptional patterns? 14. The transmission of information important for gene regulation from parent to daughter cell, without altering the actual nucleotide sequence, is called __________ inheritance. This type of inheritance is seen with the inheritance of the covalent modifications on ____________ proteins bound to DNA; these modifications are important for reestablishing the pattern of chromatin structure found on the parent chromosome. Another way to inherit chromatin structure involves DNA __________, a covalent modification that occurs on cytosine bases that typically turns off the transcription of a gene. Gene transcription patterns can also be transmitted across generations through positive _________loops that can involve a transcription regulator activating its own transcription in addition to other genes. These mechanisms all allow for cell __________, a property involving the maintenance of gene expression patterns important for cell identity. 15. MicroRNAs are noncoding RNAs that are incorporated into a protein complex called RISC, which searches the mRNAs in the cytoplasm for sequence complementary to that of the miRNA. When such a molecule is found, it is then targeted for destruction. RNAi is triggered by the presence of foreign double-stranded RNA molecules, which are digested by the Dicer enzyme into shorter fragments approximately 23 nucleotide pairs in
View Full Document
Unlocking...