MCB 2050 TEST QUESTIONS WITH CORRECT ANSWERS

MCB 2050 TEST QUESTIONS WITH CORRECT ANSWERS What are promoter proximal elements? - Answer-regulatory sequences close to the promoter that are unique to specific sets of genes Where are enhancers located? - Answer-Either upstream or downstream of the promoter What are some key properties of Promoters - Answer-1. Function within a short distance 2.Immediately upstream of initiation site 3. Position dependent -Non functional if moved 4. Orientation dependent -Drive transcription one direction only What are some key properties of enhancers - Answer-1.Long distance function 2.Upstream or downstream from start or is within introns 3. Position independent -Functional when moved 4. Orientation independent Transcriptional activators or repressors often have______ and ______ - Answer-DNA binding domains and effector domains DNA domains have ____ - Answer-conserved motifs what is a motif - Answer-Structural folds If the activation domain is between 738-823 and it gets chopped off to 792 what happens to activity - Answer-The activity would still be present but would have lost some activity If the DNA binding domain is at 1-74 and activation is 738-823 and it gets chopped to 692 what happens - Answer-DNA can still bind but there is 0 activity What are a couple common motifs? - Answer--Zinc finger for DNA recognition -Leu zipper What do zinc fingers do? - Answer-Insert into major groove of DNA bind to bases of DNA sequence recognise specific sequences What does the leucine zipper do? - Answer-It dimerizes proteins and transcription factors to facilitate their binding to DNA What is the helix-turn-helix motif? - Answer-major structure capable of binding to DNA Most common DNA-binding motif!! DNA proteins work as____ - Answer-dimers Protein dimerization _____ the complexity of DNA-binding specificity - Answer-Increases What do promoters do? - Answer-show DNA polymerase exactly where to begin making RNA (they are signals), there are also signals to show when to stop Determine the site and influence frequency How do enhancers communicate with promotors - Answer-via bending DNA What do lipid soluble hormones bind to once they have diffused through the cell - Answer-Lipid hormone receptors/transcription activators Where are the lipid hormone receptors located - Answer-cytoplasm What happens once the lipid soluble hormone binds to the receptor - Answer-the receptor hormone complex moves to the nucleus. It is now a transcription factor and it can bind to specific response elements in target genes to regulate expression How are other transcription factor activities indirectly regulated - Answer-By cell surface receptors and intracellular signal transduction cascades What is the steps of cell signaling - Answer-1. A cell sends a signal to other cells by expressing and secreting a lipid insoluble peptide hormone 2. The peptide hormone reaches a membrane imbedded receptor on the surface of the recipient cell 3. The binding of the hormone initiates a signal transduction cascade through modifications of several proteins 4. Transcription factor is activated by phosphorylation and directs expression of its target gene