Chapter 2 The Chemistry of Life Section 2 – 4 Chemical Reactions & Enzymes

9C IDENTIFY AND INVESTIGATE THE ROLE OF ENZYMES STAAR STANDARDS 9C IDENTIFY AND INVESTIGATE THE ROLE OF ENZYMES

WHAT ARE THEY? Enzymes WHY DO WE NEED THEM? NAME SOME EXAMPLES?

Enzymes PROTEINS THAT CATALYSE CHEMICAL REACTIONS IN LIVING ORGANISMS SPECIFIC PROPERTIES INCREASE RATE OF THE REACTION UNCHANGED AT THE END OF THE REACTION BECAUSE REACTIONS ARE TOO SLOW TO MAINTAIN LIFE NEED THEM CAN’T INCREASE TEMPERATURES/PRESSURE IN CELLS (FATAL)

__________  __________ Chemical Reaction KEY CONCEPT: CHEMICAL REACTIONS ALWAYS INVOLVE BREAKING BONDS OF REACTANTS AND THE FORMATION OF NEW BONDS TO FORM IN PRODUCTS __________  __________ REACTANTS PRODUCTS ARROW READS AS “CHANGES TO” OR “FORMS”

PRODUCT CHEMICAL REACTIONS TAKE PLACE IN CELLS _____________. ALL THE TIME CATALYST SUBSTRATE PRODUCT ENZYME

Many enzyme NAMES end in _____ and the beginning of the name tells what it does -ASE DNA POLYMERASE= “polymerizes” or joins monomers to make DNA PROTEASE= breaks down proteins ATP SYNTHASE= synthesizes ATP

H2CO3 H2CO3 Transport of CO2 CO2 + H20 CO2 + H20 TISSUE TO BLOOD Carbonic anhydrase BLOOD TO LUNG H2CO3 CO2 + H20 Carbonic anhydrase YOU BREATHE OUT

Transport of CO2 WITHOUT carbonic anhydrase the reaction that produces carbonic acid is _____________; only about _______ molecules of carbonic acid are produced in _____________. This rate is ______fast enough for your blood to carry away the carbon dioxide released by million of cells. VERY SLOW 2000 ONE HOUR NOT

600,000 SECOND Transport of CO2 MILLION WITH carbonic anhydrase about __________________ molecules of carbonic acid can be produced every __________. The enzyme increases the reaction rate about 10 ___________ times enabling your body to eliminate carbon dioxide efficiently. 600,000 SECOND MILLION

CELLS AND POISONS POISONOUS Your cells are always making __________ chemicals. They can die if these chemicals are not changed into ________ substances. HARMLESS HYDROGEN PEROXIDE 2H2O2 WATER + OXYGEN H20 O2 CATALASE

ENERGY IN REACTIONS Key Concept: Reactions That Release Energy Often occur spontaneously Chemical Reactions That Absorb Energy Will Not Occur Without A Source Of Energy

ENERGY FOR LIFE PROCESSES _________IS THE ABILITY TO MOVE OR CHANGE MATTER

ENERGY IN REACTIONS RELEASED ENERGY IS ___________ OR _________ EVERY TIME CHEMICAL BONDS FORM OR BREAK. STORED ENERGY _________CHANGES DETERMINE WHETHER A REACTION WILL TAKE PLACE OR NOT.

REVIEW METABOLISM IS….. SUM ENERGY SUNLIGHT ________ of all the chemical reactions in an organism ALL REACTIONS REQUIRE ______ ___________ IS THE ULTIMATE ENERGY FOR LIFE ON EARTH ENERGY SUNLIGHT

REVIEW ANABOLISM IS….. STORING LIGHT TO BUILD OR MAKE SYNTHESIZING ANY PROCESS IN AN ORGANISM THAT INVOLVES __________________ SUBSTANCES FROM SIMPLER SUBSTANCES ____________ ENERGY IN THE PROCESS SYNTHESIZING STORING PLANTS OBTAIN THEIR ENERGY DIRECTLY FROM SUNLIGHT IN A PROCESS KNOWN AS ___________________ “PHOTO” MEANS-_________________ SYNTHESIS-______________________ PHOTOSYNTHESIS LIGHT TO BUILD OR MAKE

REVIEW CATABOLISM IS….. SAME ALL RELEASE BREAKDOWN THE _____________OF COMPLEX SUBSTANCES INTO SIMPLER ONES, WHICH RESULTS IN THE ___________ OF ENERGY. RELEASE LIVING THINGS PRACTICE ANABOLISM AND CATABOLISM AT THE __________ TIME _______ THE TIME. SAME ALL

Enzymes Key Concept: Cells Use Enzymes To Speed Up Chemical Reactions That Take Place In Cells Often act as Catalyst Speed up the rate of reaction Lower activation energy

Chemical reactions need help to get started. Ex: A fire needs a match to get it started.

______________ to get a chemical reaction _______________ ENERGY REQUIRED ______________ to get a chemical reaction _______________ = ________________________ STARTED ACTIVATION ENERGY ACTIVATION ENERGY REACTANTS PRODUCTS

IT’S LIKE PUSHING A ROCK UP A HILL ONCE IT GETS TO TOP . . . IT CAN ROLL BACK ALL BY ITSELF

chemical reactions _________ CATALYSTS ___________ help chemical reactions _________ CATALYSTS HAPPEN FASTER Catalysts work by ____________ the ___________________________to get a chemical reaction started. DECREASING ACTIVATION ENERGY REQUIRED

CATALYSTS in Living Things In living systems __________ that ________________to control chemical reactions are called = _________ PROTEINS ACT AS CATALYSTS ENZYMES

Enzymes Without Enzyme With Enzyme Free Energy Progress of the reaction Reactants Products Free energy of activation

ONE ENZYME – ONE REACTION There are thousands of different enzymes in your body. Why are there so many different enzymes? Each enzyme has its own unique protein structure and shape, which is designed to match or COMPLEMENT its substrate.

FIT REUSABLE ENZYMES _____ like a _______________ to only _________of _________. Enzymes are ___________ by the reaction and ___________ FIT LOCK AND KEY ONE KIND SUBSTRATE UNCHANGED REUSABLE

EACH ENZYME IS SPECIFIC TO ONE SUBSTRATE MOLECULE OR TYPE OF MOLECULE THE _______________HYPOTHESIS STATES THAT THE ACTIVE SITE SPECIFICALLY MATCHES THE ___________OF THE SUBSTRATE MOLECULE LOCK AND KEY SHAPE enzyme active site

ENZYMES AND SUBSTRATE ARE “MADE” FOR EACH OTHER

Induced Fit A change in the shape of an enzyme’s active site Induced by the substrate

Enzyme Action: Induced Fit Model E + S ES complex E + P P S S S P

FACTORS THAT AFFECT ENZYME ACTIVITY __________ & ______________ Conditions that are TOO ACIDIC or TOO HOT cause proteins to ________ or _________ pH TEMPERATURE UNWIND DENATURE

Regulation of Enzyme Activity Most Enzymes work best at pH ~6-8 Most Enzymes work best at ~37°C which is the normal temperature of the human body (98.5 F).

THE ACTIVITY AND SHAPE OF ENZYMES IS ALSO AFFECTED BY PH ENZYMES PREFER TO WORK AT AN OPTIMUM pH. OUTSIDE OF ITS pH RANGE THE ENZYME IS DENATURED. Optimum pH pepsin amylase Rate Of Reaction 1 2 3 4 5 6 7 8 9 10 11 12 pH

EFFECT OF PH ON ENZYMES When the pH changes outwith optimal conditions, the shape of the active site of the enzyme alters and the enzyme is denatured. Movie

RATE OF REACTION OF AN ENZYME REACTION CHANGES AT DIFFERENT TEMPERATURES Optimum temperature Enzyme is denaturing Molecules gain kinetic energy Rate Of Reaction 0 10 20 30 40 50 60 70 Temperature/oC

THE RATE OF AN ENZYME CONTROLLED REACTION IS AFFECTED BY TEMPERATURE AT _____ TEMPERATURES ENZYME CONTROLLED REACTIONS GO __________. LOW SLOWLY

WHEN TEMPERATURE INCREASES THE REACTION ALSO INCREASES But this only occurs up to the optimum temperature (usually about 40oC) The temperature at which the rate of reaction is fastest is known as the optimum temperature

AFTER THE OPTIMUM TEMPERATURE THE HEAT CAUSES THE ENZYME TO DENATURE SHAPE THE ENZYME CHANGES _________AND THE ACTIVE SITE NO LONGER MATCHES THE SHAPE OF THE ________________ MOLECULE SUBSTRATE

SHAPE ACTIVE SITE CAN’T BIND CHANGES Denaturing _______ the _______ of the ______________ so enzyme ______________ to ____________ ACTIVE SITE CAN’T BIND SUBSTRATE _______________ (keeping pH and temperature constant) is ______________ for maintaining ____________________ HOMEOSTASIS IMPORTANT ENZYME FUNCTION

YOUR CONNECTIONS FEVER IS A RESPONSE TO AN _________________ HIGH FEVER IS DANGEROUS BECAUSE IT WILL ____________ ENZYMES NECESSARY FOR LIFE FEVER EXCEEDING _________CAN BE _________ INFECTION INACTIVATE 105° FATAL

ENZYMES ARE USED IN THE FOOD INDUSTRY PECTINASE _________ BREAK DOWN SUBSTANCES IN APPLE CELL WALLS AND ENABLE GREATER JUICE EXTRACTION. ________ BREAKS DOWN LACTOSE IN MILK INTO ___________ AND ________________. THIS MAKES MILK DRINKABLE FOR LACTOSE INTOLERANT PEOPLE. LIPASE GLUCOSE GALACTOSE

___________ BREAKS DOWN PROTEINS PROTEASE ENZYMES ARE USED IN LAUNDRY SOAP ___________ BREAKS DOWN PROTEINS PROTEASE LIPASE _________ BREAKS DOWN LIPIDS AMYLASE __________ BREAKS DOWN CARBOHYDRATES THESE ENZYMES ALLOW YOU TO WASH CLOTHES AT A LOWER TEMPERATURES…THUS SAVING ENERGY

ENZYMES ARE USED IN SEED GERMINATION STARCH AMYLASE SECRETED embryo plant ABSORBED MALTOSE

REVIEW ???????????? ????????????? 1 2 3 5 4 SUBSTRATE ENZYME-SUBSTRATE COMPLEX ???????????? 5 ENZYME Unchanged & Reusable ????????????? 4 PRODUCTS ?????????????

An Example HYDROLYSIS SUCROSE + H2O GLUCOSE + FRUCTOSE DEHYDRATION SYNTHESIS OR HYDROLYSIS? HYDROLYSIS GLUCOSE + FRUCTOSE

An Example SUBSTRATES SUCROSE + H2O PRODUCTS SUBSTRATES OR PRODUCTS? DISACCHARIDE SUCROSE + H2O ENZYME NAME? SUCRASE GLUCOSE + FRUCTOSE MONOSACCHARIDE SUBSTRATES OR PRODUCTS? PRODUCTS

AMINO ACIDS MAKE PROTEINS ATP

Hydrolysis or synthesis? ENZYME SUMMARY Enzyme Substrate Product(s) Hydrolysis or synthesis? Amylase Starch Maltose Hydrolysis Catalase Hydrogen peroxide Oxygen and water Protease Protein Amino acids DNA polymerase DNA nucleotide Synthesis Lipase Lipid Glycerol & fatty acids

Animation for enzymes http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter2/animation__how_enzymes_work.html