Enzymes Back when we discussed proteins we learned that one critical function of protein was to speed up chemical reactions Enzymes are the proteins that increase the rate of chemical reactions ID: 917272
Download Presentation The PPT/PDF document "Enzymes What do enzymes do, and why do w..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Enzymes
What do enzymes do, and why do we need them?
Slide2Enzymes
Back when we discussed proteins, we learned that one critical function of protein was to speed up chemical reactions.
Enzymes
are the proteins that increase the rate of chemical reactions
To understand how enzymes work, we need to see how reactions work.
Slide3enzymes
There are two types of reactions:
Spontaneous
reactions, which occur on their own and release energy.
Non-spontaneous
reactions, which do NOT occur on their own, and absorb energy.
Slide4enzymes
Now, enzymes do NOT make a non-spontaneous reaction spontaneous.
However, enzymes do speed up the rate of a spontaneous reaction. Basically, they make a reaction go faster.
Enzymes do this by lowering the
activation energy
of a reaction.
Slide5enzymes
All reactions – even those that release energy – require the addition of energy before they can proceed.
Slide6enzymes
Enzymes lower the amount of activation energy required for the reaction.
In this way, reactions can happen faster than they would in nature.
Slide7enzymes
Enzymes bind to the reactants at the
active site
, a very small part of the enzyme that fits the reactants.
Reactants are also called
substrates.
Slide8enzymes
The reaction then proceeds, and the products are released.
The enzyme is NOT used up at the end of the reaction.
I
t can be used again and again.
Slide9Denaturing
Enzymes, like all other proteins, can be
denatured.
This means that they lose their shape and function.
Several factors can denature proteins.
Excessive heat – this is why fevers can be lethalExposure to extreme levels of pH – both high and low
Exposure to high levels of salt (salinity)
Denaturing is almost always permanent and
irreversable
.
Slide10Exit Ticket
Proteins that speed up the rate of reaction are called ___________.
Activations ________ the activation energy of a reaction.
True or false: Enzymes can make a non-spontaneous reaction spontaneous.
The site on the enzymes that binds to the products, or substrates, is called the ___________________.
____________ takes place when a protein loses its shape and function.