1. ENZYMES http://hillarybio.blogspot.com/2008_09_01_archive.html

2. Types of Chemical Reactions in Your Body
anabolic: (building/creating)
smaller molecules join to form larger molecules
ex: making cell parts (growth, repair)
glucose
catabolic: (breaking down)
larger molecules broken
down into smaller ones
ex: polysaccharides
synthesis reactions
glycogen
(in animals)
starch
(in plants)
digestion reactions
monosaccharides

3. Enzymes enzymes are proteins
biological catalysts (speed up chemical reactions)
they are reusable
Enzyme Structure
each enzyme has a place called the active site
substrate is the reactant that an enzyme acts on when it catalyzes a chemical reaction
the active site is the location where the substrate binds to an enzyme
enzymes are very specific for the types of substrates they attach
most will only attach to one type of molecule
a different enzyme is therefore needed for every reaction in the body
the substrate and the active site must have well-matched shapes for binding to occur
proteins

4. Enzymes anabolic reaction catabolic reaction Induced-Fit Model
as the substrate enters the active site, the protein changes shape to better fit the substrate
the attachment of the substrate to the active site creates the enzyme- substrate complex
Lock & Key Hypothesis
each enzyme is uniquely designed to fit with its substrate (reactant in a chemical reaction) at the active site
they fit perfectly like ‘a lock & key’
anabolic reaction
catabolic reaction

5. Anabolic Chemical Reaction
Lock & Key Hypothesis
Anabolic Chemical Reaction
substrate 1.
substrates bind with the
enzyme’s active site 4.
enzyme-substrate complex forms
active site 2.
enzyme
product is released
enzyme detaches & is reused 3.
bonds are formed between 2 substrates
endothermic

6. Catabolic Chemical Reaction
Lock & Key Hypothesis
Catabolic Chemical Reaction
products are released
enzyme detaches & is reused 4. 1.
substrate binds
with enzyme’s
active site
bonds are broken
exothermic 3. 2.
enzyme-substrate complex forms
helps break bond

7. Lock & Key Hypothesis
An Example
Products

8. Denaturation of Proteins
+ heat
denaturation:
when proteins lose their specific 3D shape
washing a pure wool (protein) sweater in hot water → shrinks
egg white & yolk solidify when heated
denatured enzymes lose their functionality
substrate no longer fits the enzyme’s active site
chemical reaction won’t be catalyzed
denaturation can be caused by:
very hot temperatures
strong acids (low pH)
strong bases (high pH)
ex.
Note: Each enzyme has an ideal temperature & pH at which it works best.

9. Importance of Enzymes
Proteins make up about 15% of the mass of the average person. Protein molecules are essential to us in many different ways. A lot of our body is made from protein molecules. Muscle, cartilage, ligaments, skin and hair are mostly made of protein materials.
Larger proteins also hold us together. Smaller protein molecules play a vital role in keeping our body working properly. Haemoglobin, hormones (ex. insulin, antibodies, and enzymes are all examples of smaller proteins.
Both vegetarians and meat eaters must have protein in their diet. The protein in the food we eat is our main source of the chemical building blocks we need to build our own protein molecules.

10. Synthesizing a Paper-Clip Polymer with a Paper Enzyme
Activity
Synthesizing a Paper-Clip Polymer with a Paper Enzyme

11. Homework