1.A Enzyme structure, function

1.A.1 Function of enzymes in catalyzing biological reactions

Enzymes are biological catalysts, which, like catalysts, lower the activation energy of a biological reaction, thus increasing the rate of reaction.

“For instance Miley, why do people?”

“Waaahhh.. but how?! I can still see green around, but of course, maybe the grass is greener on the other side hehe,” Miley responds.

“The reason is without an enzyme, that reaction is slow… VERY slow.”

“Essentially then, you can say that enzymes cause a reaction to ‘run’,” Miley concludes. “Get it Jeremy, ‘run’? hehe ”:

Enzymes increase reaction rates by the magnitude of TRILLIONS, which is actually greater than the typical lab catalyst.

Because enzymes increase the reaction rates by such a magnitude, they can essentially pick and choose which reactions will or won’t occur in a cell. What a lot of power

More info: http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

1.A.2 Reduction of activation energy

Similar to catalysts, be aware that enzymes aren’t consumed or permanently altered by the reactions when they catalyzed (which is why they are called a catalyst and not a reactant). Also, enzymes don’t alter the equilibrium of a reaction (they just lower the activation energy).

1.A.3 Substrates and enzyme specificity

Reactants upon which an enzyme work are called the substrate(s).

Substrates are generally smaller than the enzyme.

The position on the enzyme to which the substrate binds (with numerous covalent bonds) is called the active site.

Enzymes are designed to work only on a specific substrate (aka reactant), or a group of closely related substrates, known as enzyme specificity.

The lock and key theory is an example of enzyme specificity, such that the active site of the enzyme has a specific shape (i.e. the key) that only fits in a specific substrate (i.e. the lock).

“I think I have the only key to your locked heart Miley.”

“Nawwwhh,” Miley laughed sarcastically.

More info: http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/activa2.swf