ENZYMES and Activation Energy OR: Why don’t you burn up in flames when you eat!

What is Energy? Energy is the ability to cause matter to move or change. All life processes are driven by energy Where does all energy come from?

Chemical Reactions When bonds are broken and reformed to make different substances. EX: ReactantsProducts C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O

What is Metabolism? Metabolism is the sum of all chemical reactions in your body - Metabolism is basically two components Literally, you are what you eat! 1.Breaking down foods for energy 2.Building new compounds to make you

What is needed to start a reaction? Energy absorbed Activation energy reactant Products Energy released

What is a Catalyst? A catalyst is anything that lowers activation energy There are basically two kinds: 1. Organic 2. Inorganic Organic catalysts are called Enzymes

Why is the activation energy lower? Energy absorbed Energy released reactant Products Activation energy

Energy absorbed Energy released Reactant Products Comparing Reactions Which line would represent a reaction without an enzyme present? With an enzyme present?

How Do Enzymes Work? Enzymes work like a lock and key. Specific enzymes work with specific substrates. enzyme substrate

How Do Enzymes Work? Each substrate fits into the enzyme’s active site. Then the enzyme controls chemical reaction.

Induced Fit The reactant an enzyme acts on is called the substrate –Enzyme binds to substrate at the active site to initiate rxn

Enzymes aren’t used up Enzymes are not changed by the reaction –used only temporarily –re-used again for the same reaction with other molecules –very little enzyme needed to help in many reactions enzyme substrateproduct active site

Enzymes can be affected by: Temperature: pH: Concentration: Neutral Battery AcidBleachBlood (7.5)

Order of amino acids Wrong order = wrong shape = can’t do its job! DNA chain of amino acids folded protein right shape! wrong shape!

Temperature Effect on rates of enzyme activity –Optimum temperature greatest number of collisions between enzyme & substrate human enzymes –35°- 40°C (body temp = 37°C) –Raise temperature (boiling) denature protein = unfold = lose shape –Lower temperature T° molecules move slower fewer collisions between enzyme & substrate

37° Temperature temperature reaction rate What’s happening here?! human enzymes

How do cold-blooded creatures do it?

pH Effect on rates of enzyme activity –changes in pH changes protein shape –most human enzymes = pH 6-8 depends on where in body pepsin (stomach) = pH 3 trypsin (small intestines) = pH 8

7 pH reaction rate stomach pepsin intestines trypsin What’s happening here?!

Concentration Concentration is how much of something there is in a particular area. Rate is how fast a reaction occurs.

Increasing enzyme concentration

ATP stores Energy ATP is the special carrier molecule that stores energy available for cell use. ATP is the energy currency of the cell; the energy source for all cell functions. ATP ADP P P energy