Biomedical Engineering Reference
In-Depth Information
14.
Briefly describe the major differences between replication and transcription.
15.
Describe how the hereditary information contained in genes within the cell's DNA is expressed
as proteins that direct the cell's activities.
16.
Six different codons code for leucine, while only one codes for methionine. Why might this be
important for regulating translation and producing proteins?
17.
Insulin (Figure 3.41) was the first protein to be sequenced biochemically. Assuming that there
were no introns involved in the process, what are the possible DNA sequences that produced
the last four amino acids in the molecule?
Phe
Gly
Val
Ile
Asn
Val
Gln
Glu
Leu
His
Gln
Ser
Tyr
Leu
Cys
-S-S-
Cys
Gln
Cys
-S-S-
Cys
Val
Leu
Ala
Ser
Glu
Gly
Asn
Ser
Tyr
Leu
Tyr
His
Val
Leu
Leu
Cys
-S-S-
Cys
Ala
Gly
Val
Asn
Glu
Glu
Arg
Gly
Phe
Phe
Tyr
Thr
Pro
Lys
Ala
FIGURE 3.41
Bovine insulin consists of two polypeptide chains that are joined by two disulfide bonds
(-S-S-). Hydrogen bonds also exist between the chains and between segments of the same chain. The three-
letter names stand for different amino acids (see Table 3.1).