Concepts of Genetics (12th Edition)
12th Edition
ISBN: 9780134604718
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino, Darrell Killian
Publisher: PEARSON
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Textbook Question
Chapter 14, Problem 16PDQ
The study of biochemical mutants in organisms such as Neurospora has demonstrated that some pathways are branched. The data shown in the following table illustrate the branched nature of the pathway resulting in the synthesis of thiamine:
Why don’t the data support a linear pathway? Can you postulate a pathway for the synthesis of thiamine in Neurospora?
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Wild-type E. coli cells can synthesize all 20 common amino acids, but some mutants, called amino acid auxotrophs, are unable
to synthesize a specific amino acid and require its addition to the culture medium for optimal growth. Besides their role in
protein synthesis, some amino acids are also precursors for other nitrogenous cell products. Consider the three amino acid
auxotrophs that are unable to synthesize glycine, glutamine, and aspartate, respectively.
Match each nitrogenous product with the mutant or mutants that would fail to synthesize it. Each mutant may fail to synthesize
more than one nitrogenous product, and some nitrogenous products may fail to be synthesized by more than one mutant.
glycine auxotrophs
glutamine auxotrophs
aspartate auxotrophs
Answer Bank
adenine
nucleotides
cytosine
nucleotides
guanine
nucleotides
uridine
nucleotides
An active site of a hypothetical serine protease with a peptide substrate bound is shown below:
This serine protease has 3 specificity pockets (S1, S2, S1') as shown in the figure above. S1 pocket has a glutamic acid in the bottom, the S2 pocket is small and hydrophobic, and the S1' pocket is deep and hydrophobic.
Based on this information you can conclude that R1 is most likely side chain of
a. Asp
b. Lys
c. Lle
d. Gly
e. Phe
Like ribonuclease A, lysozyme from T4 phage is a model enzyme for understanding the energetics and pathways of protein
folding. Unlike ribonuclease A, T4 lysozyme does not contain any disulfide bonds. A number of studies have quantified the
thermodynamic contributions individual amino acid residues and their interactions make to lysozyme folding.
An ion pair between an Asp residue and a His residue in lysozyme contributes 13-21 kJ/mol of favorable folding energy at
pH 6.0. However, this ion pair contributes much less to lysozyme folding at either pH 2.0 or pH 10.0.
Why does the Asp-His ion pair contribute more energy at pH 6.0 than at low or high pH?
At pH 10.0, Asp is protonated and His may be deprotonated.
At pH 6.0, Asp is protonated and His may be deprotonated.
At pH 2.0, Asp and His are both deprotonated.
At pH 10.0, Asp and His are both protonated.
● At pH 6.0, Asp is deprotonated and His may be protonated.
Chapter 14 Solutions
Concepts of Genetics (12th Edition)
Ch. 14 - Prob. 1NSTCh. 14 - A series of mutations in the bacterium Salmonella...Ch. 14 - HbS results from the substitution of valine for...Ch. 14 - Given that a faulty ribosomal protein is the...Ch. 14 - A couple with a child affected with DBA undergoes...Ch. 14 - Prob. 3CSCh. 14 - HOW DO WE KNOW? In this chapter, we focused on the...Ch. 14 - CONCEPT QUESTION Review the Chapter Concepts list...Ch. 14 - Contrast the roles of tRNA and mRNA during...Ch. 14 - Francis Crick proposed the adaptor hypothesis for...
Ch. 14 - During translation, what molecule bears the codon?...Ch. 14 - The chain of eukaryotic hemoglobin is composed of...Ch. 14 - Assuming that each nucleotide in an mRNA is 0.34...Ch. 14 - Summarize the steps involved in charging tRNAs...Ch. 14 - To carry out its role, each transfer RNA requires...Ch. 14 - What are isoaccepting tRNAs? Assuming that there...Ch. 14 - When a codon in an mRNA with the sequence 5-UAA-3...Ch. 14 - Discuss the potential difficulties of designing a...Ch. 14 - Prob. 13PDQCh. 14 - Prob. 14PDQCh. 14 - The synthesis of flower pigments is known to be...Ch. 14 - The study of biochemical mutants in organisms such...Ch. 14 - Explain why the one-gene: one-enzyme concept is...Ch. 14 - Why is an alteration of electrophoretic mobility...Ch. 14 - Prob. 19PDQCh. 14 - Prob. 20PDQCh. 14 - Prob. 21PDQCh. 14 - Prob. 22PDQCh. 14 - Several amino acid substitutions in the and ...Ch. 14 - Define and compare the four levels of protein...Ch. 14 - What are the two common types of protein secondary...Ch. 14 - How do covalent disulfide bonds, hydrogen bonds...Ch. 14 - Prob. 27PDQCh. 14 - List three different types of posttranslational...Ch. 14 - Prob. 29PDQCh. 14 - How does an enzyme function? Why are enzymes...Ch. 14 - Prob. 31PDQCh. 14 - Three independently assorting genes (A, B, and C)...Ch. 14 - How would the results vary in cross (a) of Problem...Ch. 14 - Deep in a previously unexplored South American...Ch. 14 - Many antibiotics are effective as drugs to fight...Ch. 14 - The flow of genetic information from DNA to...Ch. 14 - Prob. 37ESP
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