BIO 151 Exam 2 review ZehnderThis review sheet will be “graded” for completeness, meaning that you earn 5 points forsubmitting it on Moodle by Sunday night. The answer key is already posted on Moodle, soyou can check your answers after you complete it. This review does not cover everything thatwill be on the test and some things covered in this review may not be on the test.ANSWERS ARE BOLDED1. Categorize the following proteins as either being expressed from either proto-oncogenes ortumor suppressor genes: p53, Rb, E2F, cyclin, CDK, CDKI, cell division receptor.● Proto-oncogenes:○ Cyclin○ CDK○ Cell division receptor○ E2F● Tumor suppressor genes:○ P53○ Rb○ CDKI2. Using the cell division diagram, explain how a stem cell receiving a differentiation signalprevents the stem cell from self-renewing.A stem cell with a differentiation signal will bind to the differentiation receptor whichwill inhibit the cyclin-cdk complex due to the expression of CDKIs. The cell will alsonot move past the G1/S checkpoint.3. Human papillomavirus can cause cervical cancer. The virus encodes E6, a protein that bindsp53. What effect do you think E6 binding has on p53 activity?A. E6 activates p53B. E6 inactivates p53 (causes rapid growth)C. E6 mutates p53D. E6 binding marks p53 for degradation4. Explain your answer to #3 in one sentence.The inactivation of p53 causes uncontrolled cell division due to the fact the p53 is a tumorsuppressor gene.5. Describe the relationship between a genome, chromosomes, and genes?A genome is the entirety of genes in a cell or organism. Chromosomes are molecules of DNAthat are packed together. There can be many different genes on the same chromosome.6. Describe the general conditions that must be met at each of the three main cell-cyclecheckpoints.G1/S: cell has received division signal, the DNA is intact, the cell has grownenough, cell has enough nutrients.G2: DNA has fully replicated, no DNA damage, cell has grown properlyM: all chromosomes lined up correctly and are attached to microtubules.7. p53 can trigger apoptosis if certain cell-cycle events fail. How does this regulatory outcomebenefit a multicellular organism?This benefits a multicellular organism because it can stop a cell from having damagedDNA passed down through mitosis.8. Label: one phosphodiester bond (be sure to circle the entire bond), the 3’ end of themolecule, the 5’ end of the molecule. Is this RNA or DNA?5’ (Two phosphodiester bonds are between the adenosine andcytosine, and the cytosine and guanine)This is DNA3’9. Imagine that you and your colleagues are working in a lab to develop a protein synthesissystem for a new type of synthetic cell. During your brainstorming sessions, you propose thatpolycistronic mRNA would be much more useful than mRNA that is only translated into oneprotein because this would allow for multiple proteins necessary for a particular function tobe translated together. One of your colleagues says that is a good idea, but if you decide to gowith polycistronic mRNA, then you need to make sure to use a prokaryotic translationsystem. Why would it be a problem to use a eukaryotic translation system with polycistronicmRNA?It would be a problem to use a eukaryotic translation with polycistronic mRNA becauseeukaryotic translations need to start with a 5’ cap. Without this, the mRNA would notbe able to be initiated. It isn’t a problem for prokaryotic cells however because theydon’t need to bind first to a 5’ cap for the start codons to bind. (A prokaryotic ribosomethat recognizes the Shine-Dalgarno would be required)10. You are investigating an abnormal eukaryotic cell line that makes all of its mRNAs muchlonger than the mRNAs from normal cells (that is, they have more nucleotides than usual).Intrigued, you examine the proteins in these abnormal cells and note that many of them areeither much longer or much shorter than the normal proteins from non mutant cells.Assuming there is just one mutant defect in these cells, what is that defect?One possible defect is that the cells don’t splice correctly. It is possible that thespliceosomes aren’t processing the primary transcripts properly and in turn, themRNA is longer. As a result of this, stop codons could be introduced prematurely oron the flip side, the absence of splicing would result in longer proteins.11. Describe how a tRNA moves through the sites of a ribosome.tRNA binds with the A site, then is moved to the P site, and then eventually to the E site asthe ribosome shifts.12. Covalent bonds form during transcription and translation. What type of covalent bonds formsduring transcription? Translation? What do these covalent bonds link together?With transcription, phosphodiester bonds form between nucleotides in RNA.In translation, peptide bonds are formed between amino acids.13. During elongation of translation, the growing polypeptide is transferred from the tRNA inthe P site of the ribosome to the tRNA in the A site as a peptide bond is formed between thegrowing polypeptide and the newest tRNA.14. You’re studying the MSC gene, which is expressed only in mesenchymal stem cells whichare multipotent adult stem cells found in multiple tissues, including bone marrow and fattissue. Mesenchymal stem cells can self-renew by dividing and can differentiate into multipletissues including bone, cartilage, muscle and fat cells, and connective tissue like ligamentsand tendons. You want to obtain samples of the MSC gene and mRNA for your experiments.You have access to ligament cells, embryonic stem cells, and mesenchymal stem cells. Foreach of the cells below, indicate if you could get the MSC DNA, mRNA, both the DNA andmRNA or neither the DNA nor mRNA.∙ Ligament cells= DNA∙ Embryonic stem cells= DNA∙ Mesenchymal stem cells= mRNA and DNA15. Explain your answers to #14 in 1-2 sentences.Since the cells all contain the same DNA, the MSC gene is found in every cell, which is whyDNA is listed for all of them. Since the gene is only expressed in the mesenchymal cells, themRNA is also present in those cells.16. Which of the following is/are a critical region(s) of a tRNAmolecule?A. amino acid attachment site and start codonB. anticodon loop and ribosome binding siteC. stop codon and Shine-Dalgarno sequenceD. amino acid attachment site and anticodon loopE. ribosome binding site and 5′ cap17. Imagine that your lab is synthesizing a new type of cell. One of your colleagues suggests thatyour