EnzymesProteins Making Chemical Reactions Possible

11/30/15Do Now: Copy down Vocab●Enzyme=special proteins that speed up chemical reactions

●Substrate = molecules that enzymes bind to●Active site = area where chemical reactions occur●Anabolism = the building up of molecules●Catabolism = the breaking down of molecules●Denatured = the change of shape of an enzyme due to temperature or pH

●Inhibitors = molecules that slow down or stop enzymes

Amoeba Sisters VideoFill out worksheet that goes along with video

Biomolecules reviewhttps://youtu.be/IJ7xOSCEmZw

Enzymeshttps://youtu.be/XUn64HY5bug

Energy and chemical reactions●Most chemical reactions require energy to

begin - the energy required to start a chemical

reaction is called activation energy.

What are enzymes?●Enzymes are proteins which reduce

activation energy allowing chemical reactions to occur in living things

Enzymes reduce activation energy

Enzymes Act as Biological Catalysts●Catalysts are inorganic molecules that speed up

chemical reactions -

Enzymes are organic molecules that speed up reactions in living things-enzymes are not changed by the reaction they speed up

Active Site●Enzymes have an area called an active site. - the active site is where the chemical

reaction occurs

The Shape of the Enzyme Determines Function●The active site of the enzyme fits with only

one type of molecule known as the substrate.●Substrate is the molecule that the enzyme

acts on.

Enzyme Reactions●Written as : Enzyme + Substrate Enzyme + Product

ExampleCatalase + 2H2O2 ES Catalase + 2H2O +

O2 enzyme substrate enzyme product

enzyme-substrate complex

Lock & Key Model●Substrate fits into the active site like a key

into a lock●The enzyme reduces the amount of energy needed to break apart the substrate●The products of the reaction leave and make the enzyme available for more substrates

Enzymes can build molecules

Substrate molecules can only bond one way.

Substrate moleculesfit into the active site in the best position to bond Once in the active

site, the molecules of

substrate join together form a new product

Enzyme Inhibitors●Inhibitors control the rate of enzyme activity - if there is too much of an enzyme’s product,

inhibitors can slow or even stop an enzyme’s activity

●Two types of Inhibition - Competitive - Non competitive

Competitive Inhibition●The inhibitor is a molecule that can occupy part

of the active site●While the inhibitor is in the active site, substrate

can’t bind with the enzyme – inhibitors compete with the substrate for the active site

inhibitor competes inhibitor blocks the with substrate active site

Noncompetitive Inhibition●The inhibitor binds with the enzyme at a site away

from the active site.●Inhibitor causes enzyme to change shape –

prevents substrate from entering the active site

Inhibitor binds with enzyme Enzyme changes shape keeps

substrate from active site

Denatured Enzymes• Enzymes are proteins and if they are exposed to extremes of temp or pH lose their shape

- if a protein loses its shape, it loses its function - a protein that loses its shape is said to be denatured - if an enzyme is denatured, substrate can’t enter the active site

extreme temperature

or pH

Common Enzymes●Amylase - breaks down starch●Catalase – breaks down H2O2

●DNA polymerase – joins DNA nucleotides to build DNA

●Lipase – break apart fats●Lactase – breaks apart lactose – milk sugar●Protease- breaks apart protein molecules

-What does –ase in a molecules’ name imply?