BIOL 200 Lecture Notes - Lecture 3: Pyrimidine, Regular Sequence, Polynucleotide

• School: McGill University
• Department: Biology
• Course: BIOL 200
• Professor: Mathieu Roy

Document Summary

Backbone is composed of repeating phosphate-pentose units. Contains no information; it"s too regular (repeating sugar and phosphate) There is an end to end orientation or bias. 5" end: free phosphate group on the 5" carbon of the terminal sugar. 3" end: free hydroxyl on the 3" of the terminal sugar. Sequence of nucleic acids is written as 5" to 3" since this is the direction of dna and rna synthesis. Three-dimensional structure of dna was discovered by watson and crick based on analysis of x-ray diffraction patterns and model building. Two polynucleotide strands wound together to form a double helix. Watson, crick, and wilkins were awarded the nobel prize; rosalind. Franklin was responsible for the x-ray diffraction patterns but died before the prize was awarded. The sugar-phosphate backbone is on the outside of the double helix. Orientation of the polynucleotide strands in the double helix is antiparallel. End bias -> 5" and 3" ends which are antiparallel.