NEETZoologyBiotechnology - Principles and Processes
A restriction enzyme recognizes a specific 6-base pair palindromic sequence in DNA. The first three bases of this recognition site on one strand, read in the 5' 3' direction, are 5' - A A G. What will be the complete sequence of this recognition site on the complementary strand, read in the 3' 5' direction?
Options
- A3' - T T C G A A - 5'
- B3' - A A G C T T - 5'
- C5' - T T C G A A - 3'
- D3' - U U C G A A - 5'
Correct answer
A. 3' - T T C G A A - 5'
Step-by-step solution
A palindromic nucleotide sequence in DNA reads the same on the two strands when the orientation of reading is kept the same (e.g., 5' 3'). If the first three bases on one strand are 5' - A A G, the complementary strand must also start with 5' - A A G when read in the 5' 3' direction. Thus, the complementary strand in the 5' 3' direction is 5' - A A G C T T - 3'. When this complementary strand is read in the 3' 5' direction, the sequence is 3' - T T C G A A - 5'. Answer: 3' - T T C G A A - 5'