Monday, January 30, 2012

Animation about the interactions between water molecules

Here it goes the link to download an animation about the non-covalent bonds that exist between water molecules, that is, the hydrogen bonds.

Wednesday, January 25, 2012

Epoxide group

An epoxide is a functional group derived from the ether group. In fact, it is a cyclic ether, forming a ring with 3 members (2 carbons and 1 oxygen). The cyclic structure is an equilateral triangle and presents a high rigidity and structural tension.
In biochemistry, epoxides are important molecules in many metabolic processes, such as, for example, in the synthesis of cholesterol.

Thursday, January 19, 2012

Sunday, January 15, 2012

Music about proteins

Here it is one more music from Dr. Kevin Ahern (, this time about proteins. It was based on the Oh Little Town of Bethlehem.

Oh Little Protein Molecule

Instructor sings
Oh little protein molecule
You're lovely and serene
With twenty zwitterions like
Cysteine and alanine

Everyone sings
Your secondary structure
Has pitches and repeats
Arranged in alpha helices
And beta pleated sheets

Instructor sings
The Ramachandran plots are
Predictions made to try
To tell the structures you can have
For angles phi and psi

Everyone sings
And tertiary structure
Gives polypeptides zing
Because of magic that occurs
In protein fol-ding

Instructor sings
A folded enzyme's active
And starts to catalyze
When activators bind into
The allosteric sites

Everyone sings
Some other mechanisms
Control the enzyme rates
By regulating synthesis
And placement of phosphates

Instructor sings
And all the regulation
That's found inside of cells
Reminds the students learning it
Of pathways straight from hell

Everyone sings
So here's how to remember
The phosphate strategies
They turn the GPb's to a's
And GSa's to b's

Wednesday, January 11, 2012

Atomic music

Did you know that each atom produces music while suffers radioactive decay? What if suddenly we became atomic musicians, using the atoms as musical instruments? Believe it or not, there is actually people working on it. You can check the information in the following link:

If you want to try your skills as atomic musicion, you can do it here:

P.S. - Thanks for the link, Alves!

Saturday, January 7, 2012

Thursday, January 5, 2012

Thioester group

The thioester group, as its name indicates, is characterized by being derived from an ester group, in which the oxygen that is connected by a single bond to the carbon is replaced by a sulfur atom. Its chemical formula is COSR. Thioesters are obtained when a carboxylic acid reacts with a thiol.
Thioesters are very important in biochemistry, mostly as a consequence of the fact that the molecule coenzyme A (CoA) has a free thiol group which reacts with carboxylic groups to form thioesters. The best known example is the molecule of acetyl-CoA.
It is thought that thioesters may have been precursors of life, as advocated by de Duve in "Thioester World":
It is revealing that thioesters are obligatory intermediates in several key processes in which ATP is either used or regenerated. Thioesters are involved in the synthesis of all esters, including those found in complex lipids. They also participate in the synthesis of a number of other cellular components, including peptides, fatty acids, sterols, terpenes, porphyrins, and others. In addition, thioesters are formed as key intermediates in several particularly ancient processes that result in the assembly of ATP. In both these instances, the thioester is closer than ATP to the process that uses or yields energy. In other words, thioesters could have actually played the role of ATP in a "thioester world" initially devoid of ATP. Eventually, [these] thioesters could have served to usher in ATP through its ability to support the formation of bonds between phosphate groups.
By the way, as a curiosity, if the oxygen from the ester group that is replaced by sulfur is the one of the double bond, the resulting functional group is called thionoester.

Tuesday, January 3, 2012

Famous sentence (7)

"A cell of a higher organism contains a thousand different substances, arranged in a complex system. This great organized system was not discovered by chemical or physical methods; they are inadequate to its refinement and delicacy and complexity." — Herbert Spencer Jennings

Sunday, January 1, 2012