Nucleotides in both DNA and RNA are bound by phosphate ester bonds. See the following link for a detailed discussion: http://www.ncc.gmu.edu/dna/structur.htm
point mutation
the nucleotides are jointed to one another by a covalent bond between the sugar of one nucleotide and the phosphate of the next
"base"
Atom, in that DNA is constructed of nucleotides and nucleotides are constructed of atoms.
How to Password-Protect User Accounts
How to Create Strong Passwords You'll Remember
Beginner's Guide to Hotmail - #10 - Hotmail Personal Account Settings
How to Change Your Password in Windows Vista