ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
6th Edition
ISBN: 9781260406092
Author: HARTWELL, Leland, HOOD, Leroy, Goldberg, Michael
Publisher: Mcgraw-hill Education/stony Brook University
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Chapter 8, Problem 9P
The results shown in Fig. 8.5 may have struck you as incongruous because many synthetic RNAs that lacked AUG start codons (such as poly-U) were nonetheless translated into polypeptides in vitro. The reason this experiment was possible is that Marshall Nierenberg found that a high concentration of Mg2+ ions in the test tube, much higher than that found in cells, allows ribosomes to initiate translation at any position on an RNA molecule. Predict the outcomes of in vitro translation with each of the following synthetic mRNAs at both high and low Mg2+ concentrations:
| a. | poly-UG (UGUGUG...) |
| b. | poly-CAUG (CAUGCAUGCAUG...) |
| c. | poly-GUAU (GUAUGUAUGUAU...) |
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Students have asked these similar questions
The chemical bisulfite transforms cytosine (C) to uracil (U) (U). In DMSO, bisulfite is dissolved. Bisulfite was treated ribosomes. The bisulfite was subsequently removed, and the amount of protein produced was determined using a translation assay.
Why do you think we need a DMSO treated control group instead of a group not treated with anything?
Phenylalanine (Phe) is encoded by either UUU or UUC, while Tyrosine (Tyr) is encoded only by UAC and UAU. Given this, and given what you know about tRNA selection, will Phenylalanine be found in the resulting polypeptides? (Assume translation will happen even without a start codon; Also this is a bit tricky, so review the contents of the assay before answering.)
Yes, in part because phenylalanine is also coded for by UUU
Yes, because ribosomes select the amino acid regardless of the anticodon sequence
Yes, for both of the reasons listed above.
No, because it is no longer attached to the tRNA with the GAA anticodon
Suppose RNA is synthesized in vitro using the polynucleotide phosphorylase enzyme with a 3:1 ratio of C and G nucleotides (3C:1G ratio). If you were to use the resulting RNA to synthesize protein in an in vitro translation system, what percentage of the total amino acids in the protein would be made up of alanine (Ala)?
56.25%
6.25%
18.75%
0%
14%
Chapter 8 Solutions
ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
Ch. 8 - For each of the terms in the left column, choose...Ch. 8 - Match the hypothesis from the left column to the...Ch. 8 - How would the artificial mRNA 5GUGUGUGU . . . 3 be...Ch. 8 - An example of a portion of the T4 rIIB gene in...Ch. 8 - Consider Crick and Brenners experiments in Fig....Ch. 8 - The HbSsickle-cell allele of the human -globin...Ch. 8 - The following diagram describes the mRNA sequence...Ch. 8 - The amino acid sequence of part of a protein has...Ch. 8 - The results shown in Fig. 8.5 may have struck you...Ch. 8 - Identify all the amino acid-specifying codons in...
Ch. 8 - Before the technology existed to synthesize RNA...Ch. 8 - A particular protein has the amino acid sequence...Ch. 8 - How many possible open reading frames frames...Ch. 8 - Prob. 14PCh. 8 - Charles Yanofsky isolated many different trpA-...Ch. 8 - The sequence of a segment of mRNA, beginning with...Ch. 8 - You identify a proflavin-generated allele of a...Ch. 8 - Using recombinant DNA techniques which will be...Ch. 8 - Describe the steps in transcription that require...Ch. 8 - Chapters 6 and 7 explained that mistakes made by...Ch. 8 - The coding sequence for gene F is read from left...Ch. 8 - If you mixed the mRNA of a human gene with the...Ch. 8 - Prob. 23PCh. 8 - The Drosophila gene Dscam1 encodes proteins on the...Ch. 8 - Describe the steps in translation that require...Ch. 8 - Locate as accurately as possible the listed items...Ch. 8 - Concerning the figure for Problem 26: a. Which...Ch. 8 - a. Can a tRNA exist that has the anticodon...Ch. 8 - For parts a and b of Problem 28, consider the DNA...Ch. 8 - Remembering that the wobble base of the tRNA is...Ch. 8 - Prob. 31PCh. 8 - The yeast gene encoding a protein found in the...Ch. 8 - The sequence of a complete eukaryotic gene...Ch. 8 - Arrange the following list of eukaryotic gene...Ch. 8 - Prob. 35PCh. 8 - The human gene for 2 lens crystallin has the...Ch. 8 - In prokaryotes, a search for genes in a DNA...Ch. 8 - a. The genetic code table shown in Fig. 8.2...Ch. 8 - a. Very few if any eukaryotic genes contain tracts...Ch. 8 - Explain how differences in the initiation of...Ch. 8 - Do you think each of the following types of...Ch. 8 - Null mutations are valuable genetic resources...Ch. 8 - The following is a list of mutations that have...Ch. 8 - Considering further the mutations described in...Ch. 8 - Adermatoglyphia described previously in Problem 18...Ch. 8 - Prob. 46PCh. 8 - You learned in Problem 21 in Chapter 7 that the...Ch. 8 - When 1 million cells of a culture of haploid yeast...Ch. 8 - Why is a nonsense suppressor tRNATyr, even though...Ch. 8 - A mutant B. adonis bacterium has a nonsense...Ch. 8 - You are studying mutations in a bacterial gene...Ch. 8 - Another class of suppressor mutations, not...Ch. 8 - Yet another class of suppressor mutations not...Ch. 8 - At least one nonsense suppressing tRNA is known...Ch. 8 - An investigator was interested in studying UAG...Ch. 8 - Prob. 56PCh. 8 - In certain bacterial species, pyrrolysine Pyl,...Ch. 8 - Canavanine is an amino acid similar to arginine...
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- Suppose RNA is synthesized in vitro using the polynucleotide phosphorylase enzyme with a 3:1 ratio of C and G nucleotides (3C:1G ratio). If you were to use the resulting RNA to synthesize protein in an in vitro translation system, what percentage of the total amino acids in the protein would be made up of proline (Pro)? 56.25% 6.25% 42.19% 18.75% 0%arrow_forward(c) By binding one L-tryptophan molecule/monomer, the trp repressor binds to DNA to suppress syn- thesis of L-tryptophan in E. coli. Below is the amino acid sequence of the helix – (reverse) turn – helix region of the trp repressor that binds to DNA compared to the sequence of the corresponding DNA binding motif of the Prl protein, a different type of repressor protein. A diagram of the trp repressor dimer is also shown. reverse turn trp helix 4 70 Trp -Gly-Glu-Met-Ser-Gln-Arg-Glu-Leu-Lys-Asn-Glu-Leu-Gly-Ala-Gly- Ile- Prl -Ser-Glu-Glu-Ala-Lys-Glu-Glu-Leu-Ala-Lys-Lys-Cys-Gly-Ile-Thr- Val- Pri heilix trp helix 5 80 90 Trp Ala-Thr-Ile-Thr-Arg-Gly-Ser sgn-Ser-Leu-Lys-Ala-Ala- Prl Ser-Gln-Val-Ser-Asn-Trp-Phe-Gly-Asn-Lys-Arg-Ile-Arg- Prl helixarrow_forwardEven though the lac Z, Y, and A structural genes are transcribed as a single polycistronic mRNA, each gene contains the initiation and termination signals essential for translation. Predict what will happen when a cell growing in the presence of lactose contains a deletion of one nucleotide (a) early in the Z gene and (b) early in the A gene.arrow_forward
- in a clever experiment performed in 1962, a cysteine already attached to its tRNA was chemically converted to an alanine. these “hybrid” tRNA molecules were then added to a cell- free translation system from which the normal cysteine-tRNAs had been removed. When the resulting protein was analyzed, it was found that alanine had been inserted at every point in the polypeptide chain where cysteine was supposed to be. Discuss what this experiment tells you about the role of aminoacyl- tRNA synthetases during the normal translation of the genetic code.arrow_forwardSeveral experiments were conducted to obtain information about how the eukaryotic ribosome recognizes the AUG start codon. In one experiment, the gene that encodes methionine initiator tRNA (tRNAiMet) was located and changed; specifically, the nucleotides that specify the anticodon on tRNAi Met were mutated so that the anticodon in the tRNA was 5′ –CCA–3′ instead of 5′ –CAU–3′. When this mutated gene was placed in a eukaryotic cell, protein synthesis took place, but the proteins produced were abnormal. Some of these proteins contained extra amino acids, and others contained fewer amino acids than normal. a. What do these results indicate about how the ribosome recognizes the starting point for translation in eukaryotic cells? Explain your reasoning. b. If the same experiment had been conducted on bacterial cells, what results would you expect? c. Explain why some of the proteins produced contained extra amino acids while others contained fewer amino acids than normalarrow_forwardThe sequence of the sense strand of a mammalian gene is (shown). Determine the sequences of the mature RNA and the encoded protein. Assume that transcription initiates at a G approximately 25 bp downstream of the TATAATA sequence, that each 5′ splice site has the sequence AG/GUAAGU, and that each 3′ splice site has the sequence CAG/G (where / marks the location of the splice).arrow_forward
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