Essential physical features of the structure of B-DNA
Note in
particular (c) the anti-parallel, 5'
3'
directionality of either strand, the alternation of phosphate
group & deoxyribose sugars in either
strand, and the characteristic H-bond
base pairing of CG and AT
pairs between either strand, (b) the 0.34
nm (3.4 x 10-10 m)
spacing between successive base pairs and the
10-base periodicity (3.4 nm)
(3.4 x 10-9 m) of one turn of the
double helix, and (a) the presence of major
and minor grooves that
continue around the complete length of the
double-stranded molecule.
HOMEWORK: If the entire DNA content of a single human cell were arranged in linear order, would (a) you need a microscope to see it, or (b) would it fit on your desk, or (c) would it stretch out the windows of your dwelling? What is your first impression?
Calculate the answer. Use the information on this page along with one other piece of information, also in the course notes. Was your first impression right?
3'
directionality of either strand, the alternation of phosphate
group & deoxyribose sugars in either
strand, and the characteristic H-bond
base pairing of CG and AT
pairs between either strand, (b) the 0.34
nm (3.4 x 10-10 m)
spacing between successive base pairs and the
10-base periodicity (3.4 nm)
(3.4 x 10-9 m) of one turn of the
double helix, and (a) the presence of major
and minor grooves that
continue around the complete length of the
double-stranded molecule. HOMEWORK: If the entire DNA content of a single human cell were arranged in linear order, would (a) you need a microscope to see it, or (b) would it fit on your desk, or (c) would it stretch out the windows of your dwelling? What is your first impression?
Calculate the answer. Use the information on this page along with one other piece of information, also in the course notes. Was your first impression right?
Figure © 2012 TA Brown, Introduction to Genetics (1st
ed.); additional text © 2024 by Steven M. Carr