31_printout - BIOMG 3350 Lecture 31: DNA structure...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: BIOMG 3350 Lecture 31: DNA structure Jim Blankenship jeb14@cornell.edu 255-1983 219 Stimson Hall Office Hours: M,F 2:30 – 3:30 PM 219 Stimson Hall Note: Changed office hours for Friday 4/1 (1:30 – 2:30 PM) and Monday 4/4 (11:45AM – 12:45 PM). If you would like to meet me during this time period and neither of these times will work, please e-mail to schedule an appointment. Lecture 31 (3/28/11) DNA Reading assignment: pp. 945 ­6, 271 ­81, 287 ­92, 319. Problems: N&C p. 280, #8 ­1, ch. 8, #2, 10, ch. 9, #8, 11. SG pp. 107 ­11, #1 ­2, 4 ­5, 8 ­10, 13 ­14 1 BIOMG 3350 Lecture 31: DNA structure 2 BIOMG 3350 Lecture 31: DNA structure 3 BIOMG 3350 Lecture 31: DNA structure Three dimensional structure of DNA http://www.sdsc.edu/ScienceWomen/franklin.html 4 BIOMG 3350 Lecture 31: DNA structure The three ­dimensional structure of DNA The Watson and Crick DNA Double Helix  ­ 1953 Solved structure by model building based on: 1. X ­ray fiber diffrac0on data from Rosalind Franklin and Maurice Wilkins Cross indicates helical structure Figure 8 ­14 2 periodici0es: an internucleo0de distance of 3.4 Å 1 complete turn every 34Å or 10 nucleo0des/turn Diameter = 20 Å From density of DNA, diameter, length of helical turn (34Å), and 10 nuc/turn, deduced that helix must contain 2 polynucleo0de chains 2. Chargaff’s Rule on base composi0on of DNA (late 1940’s) [A] = [T], [G] = [C]; [A]/[T] = [G]/[C] = 1 [A+G] = [T+C], or [Pu] = [Py] This rule applies to DNA in all species studied 5 BIOMG 3350 Lecture 31: DNA structure 6 BIOMG 3350 Lecture 31: DNA structure 7 BIOMG 3350 Lecture 31: DNA structure Do Nelson & Cox problem #11, p. 341. 8 ...
View Full Document

Ask a homework question - tutors are online