[Campbell Biology P.466] Based on the flow-gram provided in the 'INTERPRET THE DATA' section... | Practice Question

Based on the flow-gram provided in the 'INTERPRET THE DATA' section, what is the sequence of the first 25 nucleotides synthesized, starting from the left? Ignore very short lines

  • option_A: AGCTGCTCGAAACTGTCGTACTGCT
  • option_B: AGCTTGCGAA TCTCGTCT GCTACTGCT
  • option_C: TCCGACTTGAAGAGCACTAGACTGA
  • option_D: CTGGTACGTTCTTAGACGATCAGTC

Explanation

The flow-gram represents the sequence of incorporated nucleotides, where the height of each peak indicates the number of identical nucleotides added in a single flow step. By transcribing the peaks from left to right, we get: A 1 , G 1 , C 1 , T 2 , G 1 , C 1 , G 1 , A 2 , T 1 , C 1 , T 1 , C 1 , G 1 , T 1 , C 1 , T 1 , G 1 , C 1 , T 1 , A 1 , C 1 , T 1 , G 1 , C 1 , T 1 . Concatenating these yields the 25-nucleotide sequence: AGCTTGCGAA TCTCGTCT GCTACTGCT.