Lecture 2 Intro to Nucleic Acids & Proteins
Nucleic Acid Chains
1. DNA is synthesized from deoxyribonucleoside triphosphates, otherwise known as:
dNTP’s – things that are used to make this linear structure. 2 phosphates get
removed during this process.
2. RNA is synthesized from ribonucleoside triphosphates, or: NTP’s
3. Nucleotides are linked by: phosphodiester bonds (through phosphate groups)
-DNA is double stranded while RNA is single stranded – in order for
replication & transmission of info contained in DNA strand, it needs to be
double-stranded. Basis of exactly how those strands together is mediated
through process called base pairing – ensures that base opposite of it in
opposing strand is specific base b/c not all bases are complementary to each
1. Holds DNA double helix together
2. A-T – 2 H-bonds
G-C – 3 H-bonds
H-bonds form, helping to keep 2 strands together
Strands run anti-parallel
3 forces that keep DNA together:
1. H-bonds – dipole-dipole interactions with each other
2. Van der Waals – are induced dipoles (slight variation in positive &
negative charge) – clouds of e- that when they come near each other
induce dipoles in each other.
3. Hydrophobic interactions – tendency to avoid water – stacking b/w bases
which are very hydrophobic particularly ring structure – tend to like to
stack in certain way.
- Info is always read 5’ to 3’ – DNA is composed of 2 antiparallel
strands. Has ladder-like structure. Same info present on 1 strand is on
other b/c of complementarity of bases & this redundancy is extremely
important for preservation of info.
-DNA structure is organized into double helix – ladder twists
around itself forming major groove & minor groove. Interactions with
turns of helix make DNA more stable.