Concept explainers
REFLECT AND APPLY A sample of an unknown peptide was divided into two aliquots. One aliquot was treated with trypsin; the other was treated with cyanogen bromide. Given the following sequences (N-terminal to C-terminal) of the resulting fragments, deduce the sequence of the original peptide.
Trypsin treatment
Cyanogen bromide treatment
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Chapter 5 Solutions
Biochemistry
- REFLECT AND APPLY It is possible for the codons for a single amino acid to have the first two bases in common and to differ in the third base. Why is this experimental observation consistent with the concept of wobble?arrow_forwardREFLECT AND APPLY Explain why a 50S ribosomal subunit and a 30S ribosomal subunit combine to form a 70S subunit, instead of an 80S subunit.arrow_forwardREFLECT AND APPLY Would you expect mRNA or rRNA to be degraded more quickly in the cell? Why?arrow_forward
- REFLECT AND APPLY You are studying with a friend who says that the hydrogen-bonded portions of tRNA play no important role in its function. What is your reply?arrow_forwardREFLECT AND APPLY Why is a trimming process important in converting precursors of tRNA and rRNA to the active forms?arrow_forwardREFLECT AND APPLY List three molecular changes that take place in the processing of eukaryotic mRNA.arrow_forward
- REFLECT AND APPLY You are in the process of determining the amino acid sequence of a peptide. After trypsin digestion followed by the Edman degradation, you see the following peptide fragments: LeuGlyArgGlySerPheTyrAsnHisSerGluAspMetCysLysThrTyrGluValCysMetHis What is abnormal concerning these results? What might have been the problem that caused it?arrow_forwardREFLECT AND APPLY The amino acid hydroxyproline is found in collagen. There is no codon for hydroxyproline. Explain the occurrence of this amino acid in a common protein.arrow_forwardREFLECT AND APPLY You are in the process of determining the amino acid sequence of a protein and must reconcile contradictory results. In one trial, you determine a sequence with glycine as the N-terminal amino acid and asparagine as the C-terminal amino acid. In another trial, your results indicate phenylalanine as the N-terminal amino acid and alanine as the C-terminal amino acid. How do you reconcile this apparent contradiction?arrow_forward
- REFLECT AND APPLY Is the following statement true or false? Why? The flow of genetic information in the cell is always DNARNAprotein.arrow_forwardREFLECT AND APPLY Rationalize the following observations. (a) Serine is the amino acid residue that can be replaced with the least effect on protein structure and function. (b) Replacement of tryptophan causes the greatest effect on protein structure and function. (c) Replacements such as LysArgandLeuIle usually have very little effect on protein structure and function.arrow_forwardREFLECT AND APPLY A mutation that changes an alanine residue in a protein to an isoleucine leads to a loss of activity. Activity is regained when a further mutation at the same site changes the isoleucine to a glycine. Why?arrow_forward
- BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage Learning