Wednesday, February 26, 2014

Video about cellular respiration

Tuesday, February 25, 2014

Underpants - Biochemistry

And when you thought that you have already seen everything... there is always someone that surprises you! ;)

Thursday, February 20, 2014

Dipole-dipole interaction

The dipole-dipole interaction, unlike the ionic bond (recently explained here in the blog ... ) involves non ionizable functional groups, ie without total positive or negative charges. It involves regions with partial charges...
It is a type of electrostatic interaction established between polar molecules, or at least between polar regions of biomolecules. As explained on a previous post about the concept of electronegativity, the presence of atoms with different electronegativities in a specific region of a molecule, will lead to inequalities in the distribution of the electronic cloud, which will, in turn, create regions with less electron density (and hence with partial positive charges) and regions with higher electron density (and hence with partial negative charges).
Thus, a region with a partial positive charge tends to interact electrostatically with a region of a partial negative charge, through a dipole-dipole bond.

Tattoo - Science

Friday, February 7, 2014

Song about vegetarians

Dr. Ahern got inspiration in the music Blowin' in the Wind of Elton John, to create a short song about vegetarians.

The Vegetarian's Song

How many hot dogs did you eat today?
With all of those nitrites inside?
And those heterocyclic amines in your steak
Were not something you should have tried

There's cancer my friend
Inside your bottom end
There's cancer inside your bottom end

Tuesday, February 4, 2014

Ionic bond

The ionic bond, also called salt bridge, it is, perhaps, the easiest non-covalent bond type to understand. As the name implies, it is an interaction that occurs between ions, i.e., between positive and negative charges. In biochemistry, the concept of ion is slightly different, because in a biomolecule (a protein, for example) we can have multiple regions with negative and/or positive charges. For this to happen just it is only necessary the presence of ionizable functional groups...
Therefore, when one biomolecule has a region with a negative charge (a phosphoryl or carboxyl group, for example), it can establish electrostatic interactions with a region of a biomolecule that presents a positive charge (e.g., amine or imidazole functional groups). This electrostatic attraction that occurs between the opposite charges is the ionic bond.
It is a type of interaction that occurs between polar molecules or at least between ionizable polar regions of biomolecules. As examples, we have the case of an interaction between a lysine and a glutamate in the interior of a protein or the interaction between DNA and histones, among many others...

Monday, February 3, 2014

Famous quote (25)

“The saddest aspect of life right now is that science gathers knowledge faster than society gathers wisdom.”
(Isaac Asimov)