Class Notes (808,753)
Canada (493,377)
Biochemistry (176)
BIOCH200 (124)

BIOCH 200 (January 8, 2014) - Biomolecules

4 Pages
Unlock Document

University of Alberta
Walter Dixon

*  marks information that I think is important BIOCH 200 Introductory Lecture and Biomolecules (con’t) | Nucleotides and Nucleic Acids – (January 8, 2014) Water • Overall, there is no formal charge on a water molecule. o The electron density is greatest at the oxygen atom therefore it is slightly negative  As a result, the hydrogen atoms on either side are slightly positive too counteract it. • Water molecules have an overall dipole pointing in the direction of the oxygen atom from between the two hydrogen atoms. (this is a net dipole) • Water molecules will interact with each other via hydrogen bonding o *PLEASE KEEP IN MIND THAT:  Hydrogen bonding occurs between molecules and NOT within molecules *  marks information that I think is important • The covalent bond between the hydrogen atoms and the oxygen atom IN a water molecule is NOT a “hydrogen bond” o *Since the oxygen atom has an abundance of electrons (2 lone pairs), it is the hydrogen bond DONATOR and the hydrogen atoms are therefore hydrogen bond acceptors. o These hydrogen bonds form and break all the time o *Each water molecule can theoretically participate in the formation of 4 hydrogen bonds  2 hydrogen atoms to act as hydrogen bond acceptors  2 lone pairs on the oxygen atom to act as hydrogen bond donators o *However, the number of hydrogen bonds that ACTUALLY occur in a water molecule is approximately 3. (In most cases, the oxygen atom will only participate in 1 hydrogen bond, not 2) o Hydrogen bonds are longer than covalent bonds and therefore weaker  *Generally, the longer the bond, the weaker it is.  *Also, they can only form between the hydrogen atom and either oxygen, nitrogen, or fluorine • In ice, the molecules are more organized and this lends to a more stable interaction… the formation of a lattice o *Ice is characterized by the lattice formation that the molecules take on o *Water is characterized by fluctuating h-bond formation and disassembly (constantly) Van der Waals forces • There are 2 types: o Dipole-dipole interactions  Slightly positive atoms of a molecule are attracted to slightly negative atoms of another molecule o London Dispersion Forces  Is due to slight differences in electronegativity of atoms within a molecule that has no overall dipole *  marks information that I think is important  Occasionally a dipole forms on its own but only for a short instance and
More Less

Related notes for BIOCH200

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.