Chapter Questions
Draw one of the 20 amino acids and label the amino group, the carboxyl group, the R group (side chain), and the $\alpha$ carbon.
What are the three major groups of amino acids as categorized by the properties of their R groups? How do the chemical properties of each group affect protein shape?
How do peptide bonds, hydrogen bonds, ionic bonds, disulfide bridges, and noncovalent interactions (van der Waals forces and the hydrophobic effect) define a protein's four levels of structure?
What ultimately determines the three-dimensional shape of a protein?
A mutation leads to a change in one amino acid in a protein. The result is that the protein no longer functions properly. How is this possible?
What are the relationships among the template strand of DNA, the codons in mRNA, anticodons in tRNA, and amino acids?
Which polypeptide sequences would you expect to result from a synthetic mRNA with the repeating sequence 5'-UUUGGGUUUGGGUUUGGG-3'?
What are the steps of translation? Name and describe each one.
Bacterial DNA containing an operon encoding three enzymes is introduced into chromosomal DNA in yeast (a eukaryote) in such a way that it is properly flanked by a promoter and a transcriptional terminator. The bacterial DNA is transcribed and the RNA correctly processed, but only the protein nearest the promoter is produced. Why?
What are two ways that proteins can acquire new functions in the course of evolution? Explain each one.
In the evolution of resistance in the malaria parasite to pyrimethamine, what do you think happened to the mutations that decreased survival or reproduction of the parasites?