Name: Directions: Fill in your ID AND NAME on the scantron and bubble in the letters and numbers. For the following questions, if the answers are preceded by letters, select one answer. If the answers are preceded by numbers, then each one requires you to indicate whether it is A correct or B incorrect. If you wish you can mark your answers on this sheet – you may keep it. I will post the key online this evening. Each question is worth 2.77 points. 1. Embryonic blastocyst cells differ from adult skin stem cells because skin stem cells are A. Pluripotent B. Multipotent C. Totipotent D. Omnipotent Two second messengers A and B are synthesized at 10 molecules per second, but have different lifetimes. A lasts 1 second per molecule whereas B lasts 60 seconds. Which of the following would be true or false (each answer is a separate problem so you should mark A for T or B for F). Do the math, pay attention to turn-over time. 2. There would be 600 molecules of B at steady state. T 3. B would make a better rapid signaling molecule because its concentration is high. F 4. If the cell started synthesizing both molecules at 100 molecules per second but didn’t change the turnover time there would be 110 molecules of A after 2 s. F 5. A would make a better rapid signaling molecule because its steady state concentration is low. T 6. If you change the turnover time (100 times) instead of the synthesis rate (10X) the increase in concentration would be faster. F 7. If the sequence of a eukaryotic gene’s promoter region were to mutate, what might be the consequence? A. The sigma factor could not bind B. No transcription would occur C. Transcription of this particular gene would not occur D. No translation would occur. E. There would be no consequences 8. The central Dogma A. DNAprotein  RNA B. RNA  DNA  protein C. DNA RNA  protein D. Protein  DNA  RNA E. Protein  RNA  DNAUse this Diagram for the next three questions: 9. Which of the following would block the SR signal from reaching the nucleus? A. If TK1 not only targeted TK2, but also targeted TFa. B. If TK2 not only targeted TFa but also target TK1. C. If TFa caused the production of a phosphatase that targeted TK2. D. If TK2 caused ubiquitin-dependent proteolysis of TFa. 10. Which of the following would set up a positive feedback loop? A. If TK1 not only targeted TK2, but also targeted TFa. B. If TK2 not only targeted TFa but also target TK1. C. If TFa caused the production of a phosphatase that targeted TK2. D. If TK2 caused ubiquitin-dependent proteolysis of TFa. 11. Which of the following would set up an oscillating output from a constantly present signal? A. If TK1 not only targeted TK2, but also targeted TFa. B. If TK2 not only targeted TFa but also target TK1. C. If TFa caused the production of a phosphatase that targeted TK2. D. If TK2 caused ubiquitin-dependent proteolysis of TFa.12. In lane 1 I have added a sample of linear DNA. In lane 2 I pre-treated the DNA with a protein that cuts the DNA in two unequal pieces. Which of the following images shows the correct arrangement of bands? 13. APC stands for adenomatous polyposis coli protein. In people with a nonfunctioning mutation in the protein (the protein doesn’t work) the chance of colorectal cancer by age 40 is 100% because of an over-proliferation of cells in the crypts of the intestinal epithelium. In healthy cells a signal (S) is necessary to cause proliferation, when APC (not shown) is non-functional, no signal is necessary for cell proliferation. S is signal, the snakey thing is the receptor, a dashed line shows several steps TF is a transcription factor leading to expression of genes related to proliferation. What might un-mutated APC do in a HEALTHY cell? Pick the BEST answer A. APC is a kinase for the receptor B. APC is a kinase for TF C. APC leads to ubiquitin mediated degradation of TF D. APC blocks endocytosis of the receptor. E. None of the above 1 2 1 2 A. B. C. D. TF S14. The phrase “survival of the fittest” is often used to summarize the complex concept of evolution by natural selection. Why is the phrase misleading? A. The phrase doesn’t account for artificial selection B. The survivor must pass on his/her/its genes to offspring for evolution to happen. C. Natural selection does not select for fitness D. You can’t live forever, but evolution still occurs E. None of the above 15. A GTPase is in its inactive state when A. It hydrolyzes GTP B. It is bound to GDP C. It is bound to GTP D. It is activated by a kinase E. It is ubiquitinated 16. A small number of surface receptors can ultimately generate a large intracellular response, as each step of the pathway is often expanded by signal _________. A. amplification B. transduction C. negative feedback D. second messengers E. Any of the above 17. _______ help adhere cells to one another, whereas ________ help to anchor cells to the ECM A. Adherins/gap junctions B. Gap junctions/tight junctions C. Tight junctions/integrins D. Cytoskeleton/desmosomes 18. AAP is a cytosolic protein that is phosphorylated in its active state. Which of the following could inactivate the protein temporarily? A. A kinase B. A phosphatase C. Ubiquitin mediated degradation D. Receptor endocytosis E. Any of the above19. Transcription begins at a RNA polymerase-binding site called a _____. A. ribosome B. replicator C. inducer D. promoter 20. In _________, a ribosome assembles a polypeptide, whose amino acid sequence is specified by the nucleotide sequence in the mRNA (which itself is a copy of the template DNA). A. transcription B. translation C. replication D. synthesis 21. Most eukaryotic genes contain coding sequences called ________ that are interspersed with noncoding sequences. A. introns B. exons C. codons D. DNA 22. Amino acids are transported to the ribosome for use in building the polypeptide by A. mRNA molecules. B. tRNA molecules. C. DNA polymerase molecules. D. rRNA molecules. E. DNA ligase molecules. 23. The different components of the protein synthesizing machinery include all of the following except A. mRNA. B. tRNA. C. ribosomes. D. amino acids. E. RNA polymerase.24. If the sequence of bases in a section of template DNA is 5’ ATCGCTCC 3’, what is the corresponding sequence of bases in mRNA? A. 5’ TAGGCTGG 3’ B. 5’ UAGCGAGG 3’ C. 5’ GGAGCGAU 3’ D.