Section
How would this mutation affect attenuation of the tryptophan operon? Explain your answer.
Would formation of the
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Chapter 12 Solutions
Genetic Analysis: An Integrated Approach (3rd Edition)
- What is the primary difference betwee class I and class II aminoacyl-tRNA synthetases. a. Class I synthetases acylate the terminal 2’ hydroxyl group of tRNAs; Class II synthetases acylate the terminal 3’ hydroxyl group of tRNAs. b. Class I synthetases acylate the terminal 3’ hydroxyl group of tRNAs; Class II synthetases acylate the terminal 2’ hydroxyl group of tRNAs. c. Class I synthetases acylate tRNAs with hydrophobic amino acids; Class II synthetases acylate tRNAs with polar amino acids. d. Class I synthetases acylate tRNAs with polar amino acids; Class II synthetases acylate tRNAs with hydrophobic amino acids.arrow_forwardIs the Aminoacyl tRNA synthetases in human cells specialized or non specialized? Explain.arrow_forwardDNA in human mitochondria encodes 22 different tRNA molecules. However, 32 different tRNA molecules are required for translation of proteins within mitochondria. Explain.arrow_forward
- Many clinically relevant mitochondrial diseases are caused by mutations in mitochondrial genes affecting tRNAs. For example, one form of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) is caused by a point mutation in the gene encoding the mitochondrial tRNA whose anticodon recognizes the codons 5' UUA and 5' UUG. The mutation makes the aminoacylation of this tRNA inefficient. a. The rate of synthesis of most mitochondrial proteins is either unaffected or slightly decreased in MELAS cells, but one mitochondrial protein called NAD6 is synthesized at only 10% of the normal rate. How is it possible that the translation of this single mitochondrial protein might be affected specifically?arrow_forwardIn this chapter you were introduced to nonsense suppressor mutations in tRNA genes. However, suppressormutations also occur in protein-coding genes. Using thetertiary structure of the β subunit of hemoglobin shownin Figure 9-3(c), explain in structural terms how a mutation could cause the loss of globin protein function. Nowexplain how a mutation at a second site in the same protein could suppress this mutation and lead to a normalor near-normal protein.arrow_forwardDescribe the two sequential reactions that occur in the activesite of aminoacyl-tRNA synthetases.arrow_forward
- Consider the now dominant variant of the SARS-CoV-2 called the D614G mutation: a) The mutation changes an Aspartate (D, Asp) to a Glycine (G, Gly) at nucleotide position 614 (that’s why it’s called the D614G mutant) in the S1 subunit of the Spike protein. Using only the information above and a codon table, what are the mRNA codon sequences of the 2019-dominant and 2020-dominant Spike proteins? Note the figure above is not needed toanswer the question. Report in 5’ to 3' orientation __________________________________________ b) What type of substitution is this? In your answer, address the following: • The expected substitution in base sequence (e.g., A à C)• If the mutation is synonymous, nonsynonymous, or a frameshift• If the mutation is a transition or a transversion c) The mutation increases infectivity by reducing the stability of the Spike protein such that it can remain in the open conformation more often. The open conformation increases the chances of binding to the host ACE2…arrow_forwardDescribe the processing events that occur during the production of tRNA in E. coli.arrow_forwardAlthough aminoacyl-tRNA synthetases make few errors, occasionally an error does occur. How can these errors be detected and corrected?arrow_forward
- The covalent attachment of an amino acid to a tRNA is an endergonic reaction. In other words, it requires an input of energy for the reaction to proceed. Where does the energy come from to attach amino acids to tRNA molecules?arrow_forwardExplain whether the specificity of lysine incorporation by lysyl-tRNA synthetase depends on tRNA or lysine, how does it work ?arrow_forwardWhat is the role of aminoacyl-tRNA synthetase? The ability of aminoacyl-tRNA synthetases to recognize tRNAs has sometimes been called the “second genetic code.” Why has the function of this type of enzyme been described this way?arrow_forward
- Biology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage Learning