What is pi, and how did it originate? Succinctly, pi--which is written as the Greek letter for p, or --is the ratio of the circumference of any circle to the diameter of that circle. Regardless of the circle's size, this ratio will always equal pi. In decimal form, the value of pi is approximately 3.14.
Inverted repeat. An inverted repeat (or IR) is a single stranded sequence of nucleotides followed downstream by its reverse complement. The intervening sequence of nucleotides between the initial sequence and the reverse complement can be any length including zero. When the intervening length is zero, the composite sequence is a palindromic sequence.
A: Palindrome, B: Loop, C: Stem. A palindromic sequence is a nucleic acid sequence on double-stranded DNA or RNA wherein reading 5' (five-prime) to 3' (three prime) forward on one strand matches the sequence reading backward 5' to 3' on the complementary strand with which it forms a double helix.ecause a DNA sequence is double stranded, the base pairs are read, (not just the bases on one strand), to determine a palindrome. Many restriction endonucleases (restriction enzymes) recognize specific palindromic sequences and cut them.