Chapter 14 Gene Expression From Gene to Protein

Biology-Ch 14 Focus Questions 14.1 a. In what 3 ways does RNA differ from DNA? b. Fill in the following sequence in the flow of genetic information, often called the Central Dogma. Above each arrow, write the name of the process involved. 14.2 Practice using the codon table in your textbook. Determine the amino acid sequence for a polypeptide coded for by the following mRNA transcript (written 5' to 3'): AUGCCUGACUUUAAGUAG 14.3 Describe the key steps of transcription as they occur in eukaryotes: A. B. C. 14.4 How does the mRNA that leaves the nucleus differ from pre-mRNA? 14.5 Using some of the codons and the amino acids you identified in Focus Question 14.2, fill in the following table. DNA Triplet mRNA Codon Anticodon 35 Amino Acid 35 5'3' GCA methionine TTC UAG 14.6 In the following diagrams of polypeptide synthesis, name the stages (1-4), identify the components (a-1), and then briefly describe what happens in each stage. (This diagram does not include the initiation stage.) h. Chapter 14: Gene Expression: From Gene to Protein 115 16. Translocation in the process of translation involves a. the hydrolysis of GTP. b. movement of the tRNA in the A site to the P site. c. movement along the mRNA a distance of one triplet. d. the release of the unattached tRNA from the E site. e. all of the above 17. Which of the following types of molecules cata-lyzes the formation of a peptide bond? a. RNA polymerase b. rRNA c. mRNA d. aminoacyl-tRNA synthetase e tRNA 18. Which of the following is not true of an anticodon? a. It consists of three nucleotides. b. It lines up in the 5'-3' direction along the 5'→3 mRNA strand. c. It extends from one loop of a tRNA molecule. d. It may pair with more than one codon. e. Its base uracil base-pairs with adenine 19. Changes in a polypeptide following translation may involve a. the addition of sugars or lipids to certain amino acids. b. the enzymatic addition of amino acids at the begin-ning of the chain. the removal of poly-A from the end of the chain. d. the addition of a 5' cap of a modified gutnosine. all of the above. 20. Several proteins may be produced at the same time from a single mRNA by a. the action of several ribosomes in a string, called a polyribosome. b. several RNA polymerase molecules working sequentially. e signal peptides that associate ribosomes with rough ER. d. the action of several promoter regions, e. the involvement of multiple spliceosomes. 21. A signal peptide a. is most likely to be found on cytosolic proteirs pro-duced by bacterial cells. b. directs an mRNA molecule into the lumen of the ER. e. is a sign to bind the small ribosomal unit at the initia-hon codon d. would be the first 20 or so amino acids of a protein destined for a membrane location or for secretion from the cell. e. is part of the UTR following the 5' cap. 22. A nucleotide deletion early in the coding sequence of a gene would most likely result in a nonsense mutation. b. a frameshift mutation. c. multiple missense mutations. d. a nonfunctional protein. e. all of the above. 23. The type of mutation responsible for sickle-cell anemia is a a silent mutation. b. a nucleotice-pair insertion. e a point mutation. d. a nucleotide-pair substitution. e. Both cand d describe the type of mutation. Use the following diagram of coupled transcription and translation in bacteria to answer questions 24 through 28. b. 24. Which letter refers to an mRNA molecule? 25. Which letter refers to a forming polypeptide? 26. Which letter refers to RNA polymerase? 27. Which letter refers to a ribosome? 28. Which letters indicate structures or molecules con-taining nucleotides... a. a and b b. a, b, and d c. b, c, and d d. b, d, and e e. cand d 14.7 What determines if a ribosome becomes bound to the ER? 14.8 Define the following terms, and explain what type of small-scale mutation could cause each of these types of mutations. a. Silent mutation b. Missense mutation c. Nonsense mutation d. Frameshift mutation Name: Chapter 14 Active Reading Guide From Gene to Protein This is going to be a very long journey, but it is crucial to your understanding of bicology. Work on this chapter a single concept at a time, and expect to spend at least 6 hours to truly master the material. To give you an idea of the cepin and time required, took over 5 hours to write this Reading Guide! You will need even longer to complete it and leam the information, Good luck, and take your time Overview 1. What is gene expression? Section 1 2. What situation did Archibald Garod suggest caused "inborn errors of metabolism"? 3. Describe one example Garrod used to illustrate his hypothesis. 2 4. Slate the hypothesis formulated by George Beadle while studying eye color mulations in Crosophila 5. What sonategy did Beadle and Tatum adopt to lest this hypothesis? 6. Which organism cid Beadle and Tatum use in ther research? How did this organism's nutritional requirements facilitate this research? translation 7. How were Neurospora spores treated to increase the mutation race? 8. Cire two significant findings that resulted from the research of Boadile and Tatun 9. What revision of detail (but not of basic principle) did the hypothesis undergo as more information was gained? Winte this restatament and then highlight it. This is an important concept! Basic Principles of Transcription and Translation This section will introduce you to the processes anc associated terminology in the form of an overview. Once you have the big picture, you will take a closer look in the next few corncepts 10. From the first paragraph in this section, find three ways in which RNA differs from DNA 11. What are the monomers of DNA and RNA? Of proteins? 12. Define each or these processes that are essential to the formation of a pruusi Iranscription 13. Complete the following table to summarize each process Tempate Product Synthesized Location in the Eukaryotic Cell Transcription Translation