Identify the structure labeled as number 18. 

 Which has the shortest wavelength?

 A codon is _______ nucleotides long, and there are _______ different possible codons in total. 

 If a sequence of one strand of DNA is 5?-ATGATGT-3?, the complementary strand must be _______. (Include correct orientation.) 

 Suppose the DNA of a gene contains five regions: A, B, C, D, and E, in that order. Regions A, B, and D are located in introns, while regions C and E are located in exons. What is the order of the regions in the pre-mRNA transcribed from that sequence? 

 In eukaryotic cells, translation occurs in the _______ and transcription occurs _______. 

 Ribosomes are a collection of _______ that are needed for _______. 

 During replication, the new DNA strand is synthesized 

 If _______ was nonfunctional, then DNA polymerase could not replicate the 3?-to-5? strand of template DNA. 

 Greater numbers of errors are found in mRNA than in replicated DNA from the same gene sequence, because RNA polymerase.