The following figure contains several examples of the Shine–Dalgarno sequence. Using the seven Shine–Dalgarno sequences from E. coli, determine the consensus sequence and describe its location relative to the start codon.

The line below represents a mature eukaryotic mRNA. The accompanying list contains many sequences or structures that are part of eukaryotic mRNA. A few of the items in the list, however, are not found in eukaryotic mRNA. As accurately as you can, show the location, on the line, of the sequences or structures that belong in eukaryotic mRNA; then, separately, list the items that are not part of eukaryotic mRNA.
5′ ____________________________ 3′

a. stop codon
b. poly-A tail
c. intron
d. 3' UTR
e. promoter
f. start codon
g. AAUAAA
h. 5' UTR
i. 5' cap
j. termination sequence

Explain why the one-gene:one-enzyme concept is not considered totally accurate today.

After completing Problem 17, carefully draw a line below the mRNA to represent its polypeptide product in accurate alignment with the mRNA. Label the N-terminal and C-terminal ends of the polypeptide. Carefully draw two lines above and parallel to the mRNA, and label them 'coding strand' and 'template strand.' Locate the DNA promoter sequence. Identify the locations of the  nucleotide and of a transcription termination sequence.

Identify and describe the steps that lead to the secretion of proteins from eukaryotic cells.

Table C contains DNA-sequence information compiled by Marilyn Kozak (1987). The data consist of the percentage of A, C, G, and T at each position among the 12 nucleotides preceding the start codon in 699 genes from various vertebrate species and at the first nucleotide after the start codon. (The start codon occupies positions +1 to +3 and the first nucleotide immediately after the start codon occupies position +4) Use the data to determine the consensus sequence for the 13 nucleotides ( -12 to -1 and +4) surrounding the start codon in vertebrate genes.

Many antibiotics are effective as drugs to fight off bacterial infections because they inhibit protein synthesis in bacterial cells. Using the information provided in the following table that highlights several antibiotics and their mode of action, discuss which phase of translation is inhibited: initiation, elongation, or termination. What other components of the translational machinery could be targeted to inhibit bacterial protein synthesis?

The flow of genetic information from DNA to protein is mediated by messenger RNA. If you introduce short DNA strands (called antisense oligonucleotides) that are complementary to mRNAs, hydrogen bonding may occur and 'label' the DNA/RNA hybrid for ribonuclease-H degradation of the RNA. One study [Lloyd et al. (2001). Nucl. Acids Res. 29:3664–3673] compared the effect of different-length antisense oligonucleotides upon ribonuclease-H–mediated degradation of tumor necrosis factor (TNFα) mRNA. TNFα exhibits antitumor and pro-inflammatory activities. The following graph indicates the efficacy of various-sized antisense oligonucleotides in causing ribonuclease-H cleavage. What factors other than oligonucleotide length are likely to influence antisense efficacy in vivo?

The flow of genetic information from DNA to protein is mediated by messenger RNA. If you introduce short DNA strands (called antisense oligonucleotides) that are complementary to mRNAs, hydrogen bonding may occur and 'label' the DNA/RNA hybrid for ribonuclease-H degradation of the RNA. One study [Lloyd et al. (2001). Nucl. Acids Res. 29:3664–3673] compared the effect of different-length antisense oligonucleotides upon ribonuclease-H–mediated degradation of tumor necrosis factor (TNFα) mRNA. TNFα exhibits antitumor and pro-inflammatory activities. The following graph indicates the efficacy of various-sized antisense oligonucleotides in causing ribonuclease-H cleavage. What general conclusion can be drawn from the graph?