Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 15, Problem 5P
The human mitochondrial genome includes no genes for tRNA synthetases.
| a. | How are mitochondrial tRNAs charged with amino acids? |
| b. | Given your answer to part (a), explain how AUA can specify Met in mitochondria but Ile in the nucleus. |
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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?
How many ATP and GTP molecules would be hydrolyzed in the synthesis of a 125 amino acid protein? Explain why this is a good argument for careful regulation of gene expression (especially considering that most proteins are larger than 125 amino acids).
A recent genome sequencing project for the bacterium Burkholderia mallei has identified a new protein with high similarity to the lysylphosphatidylglycerol flippase enzyme. A short section of the new protein sequence is shown below. TVEVNAPGDVQKALSELQQINDGRLDIRI (a) Are any reverse turns likely to be present? Explain your answer. (b) Are any beta-strands likely to be present? Explain your answer. (c) Are any alpha helices likely to be present? Explain your answer. (d) Is any supersecondary structure likely to be present? Explain your answer. (e) Identify two residues that are likely to be buried in the core of the folded protein. Explain your answer. (f) Identify two residues that are likely to be hydrogen bonded to each other. Explain your answer.
Chapter 15 Solutions
Genetics: From Genes to Genomes
Ch. 15 - Match each numbered item with the most closely...Ch. 15 - Assuming human cells have on average 1000...Ch. 15 - Reverse translation is a term given to the process...Ch. 15 - The human nuclear genome encodes tRNAs with 32...Ch. 15 - The human mitochondrial genome includes no genes...Ch. 15 - How do you know if the halibut you purchased at...Ch. 15 - Is each of these statements true of chloroplast or...Ch. 15 - Suppose you are characterizing the DNA of a...Ch. 15 - An example of a gene-targeting DNA plasmid vector...Ch. 15 - Which of the following characteristics of...
Ch. 15 - The Saccharomyces cerevisiae nuclear gene ARG8...Ch. 15 - The so-called hypervariable regions HV1 and HV2 of...Ch. 15 - Suppose a new mutation arises in a mitochondrial...Ch. 15 - Describe at least two ways in which the...Ch. 15 - Why are severe mitochondrial or chloroplast gene...Ch. 15 - Suppose you are examining a newly found plant...Ch. 15 - A form of male sterility in corn is inherited...Ch. 15 - Plant breeders have long appreciated the...Ch. 15 - A mutant haploid strain of Saccharomyces...Ch. 15 - Prob. 20PCh. 15 - What characteristics in a human pedigree suggest a...Ch. 15 - The first person in the family represented by the...Ch. 15 - In 1988, neurologists in Australia reported the...Ch. 15 - If you were a genetic counselor and had a patient...Ch. 15 - Kearns-Sayre syndrome KSS, Pearson syndrome, and...Ch. 15 - Many clinically relevant mitochondrial diseases...Ch. 15 - Leigh syndrome is characterized by psychomotor...Ch. 15 - All mutations in mitochondrial genes ultimately...Ch. 15 - How could researchers have determined that the...
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