Figure 1.
Antiparallel-stranded DNA. The two strands are complimentary, meaning
that each attracts specifically to its
partner, and are often unique. As a
consequence of the pairing, ‘genes’ are usually only encoded on one strand. In
chromosomal coding DNA, in which the two strands are antiparallel, Adenine (A)
pairs with Thymine (T) and Guanine (G) pairs with Cytosine (C). In RNA, T is
replaced with Uracil (U). The G-C interaction holds two strands together more
tightly than the A-T interaction because there is one more Hydrogen bond
between the nitrogenous bases, thus organisms that must thrive in
high-temperature environments like deep sea vents tend to have G/C-rich genomes
that were naturally selected to keep their genetic material from unraveling.
Though not so apparent in this figure, the purine (A,G) and pyrimidine (C,T,U)
bases are relatively free to rotate about the bond to the sugar backbone, hence
both parallel and antiparallel strand orientations are allowed.
Anyway, I haven't finished that yet because I've been working on two presentations that are conveniently scheduled back-to-back this coming week (Sunday and Monday). One of them is my thesis, which was "done" three months ago but, of course, not finished. While I'm riding that tangent, let me just express my dissatisfaction with academia (again) because my advisor tried to scold me when I jauntily noted that "Science is never actually done." And that's why I need a break. Maybe forever.
Anyway, I am excited to finally defend this thesis while my committee is present.
I'd say "Wish me luck", but I don't need it. Maybe I should do that anyway...
'Til next time.
