Chapter 6
25
11 September, 2006 Chapter 6 DNA Structure
-
Upload
phylicia-fauna -
Category
Documents
-
view
12 -
download
0
description
Chapter 6. DNA Structure. 11 September, 2006. Overview. The classical DNA structure is an antiparallel duplex of polynucleotides . The two strands of DNA have complementary sequence because of base pairing interactions. - PowerPoint PPT Presentation
Transcript of Chapter 6
Overview• The classical DNA structure is an antiparallel duplex of
polynucleotides .• The two strands of DNA have complementary sequence because of base
pairing interactions.• The major groove of a DNA duplex is carries accessible information
about the sequence.• DNA can exist in alternative structures.• DNA molecules can melt and anneal.• The linking number, composed of twist and writhe is a property of
covalently closed circles.• DNA in cells is negatively supercoiled.• Topoisomerases cleave and rejoin strands to change the supercoiling
state of DNA.• RNA is usually single stranded, and form complex seconbdary and
tertiary structures, including some that have enzymatic activity.