Goal 2.04: Enzymes

“Helper” Protein molecules

“Enzyme” music videohttp://casesblog.blogspot.com/2009/04/music-video-enzyme-what-are-you-doing.html

Recall? Processes of life

making molecules synthesis

breaking down molecules digestion

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Nothing works without enzymes! How important are enzymes?

ALL chemical reactions in living organisms require enzymes to work building molecules

synthesis enzymes

breaking down moleculesdigestive enzymes

enzymes speed up reactions “catalysts”

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enzyme

enzyme

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How Do Enzymes Work?EN

ERG

Y

TIME

ACTIVATION ENERGY = energy required to cause the reaction to occur.

ENER

GY

TIME

ACTIVATION ENERGY = energy required to cause the reaction to occur.

Enzymes reduce the activation energy!Enzymes reduce the activation energy!?

Enzymes are PROTEINS! Each enzyme is the specific helper to

a specific reaction each enzyme needs to be the right shape

for the job enzymes are named for the reaction

they help sucrase breaks down sucrose proteases breakdown proteins lipases breakdown lipids DNA polymerase builds DNA

I get it!They end

in -ase

SPECIFICITY!

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

How enzymes work:http://highered.mcgraw-hill.com/

sites/0072495855/student_view0/chapter2/

animation__how_enzymes_work.html

Enzyme = reusable protein that can make or break molecules

Substrate = substance to be changed

Products = substances produced

Active Site = location on enzyme where substrate fits

Is this a digestive or synthesizing enzyme?Is this a digestive or

synthesizing enzyme?

Enzyme-Substrate Complex = enzyme and molecules temporarily joined

It’s shape that matters! Lock & Key model

shape of protein allows enzyme & substrate to fit

specific enzyme for each specific reaction

Enzyme

Substrate

1

2

3

Lactose Intolerant? You need some LACTASE!

Lactose = sugar found in milk Lactase = enzyme that breaks down lactose.

QuickLab: Building an enzyme model.

Prep VL1 and Do Virtual Lab 1 (potato only):Catalase Action by Living Tissue

What Affects Catalase Activity?http://bioweb.wku.edu/courses/Biol114/enzyme/enzyme2.asp

Regulation of Enzymes Correct protein structure

correct order of amino acids why? enzyme has to be right shape

Temperature why? enzyme has to be right shape

pH (acids & bases) why? enzyme has to be right shape

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Effect on rates of enzyme activityEnzyme Concentration

increase the amount of enzyme = increases how fast the reaction happens more enzymes = more frequently they collide

with substrate

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Enzyme concentration

amount of enzyme

reac

tio

n r

ate

As concentration increases…

Re

act

ion

s in

crea

se…

Why does the reaction rate level off?

Enzyme action uses up substrate!

Substrate Concentration Effect on rates of enzyme activity

as increase amount of substrate = increases how fast the reaction happens

more substrate = more frequently they collide with enzyme

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Substrate concentration

amount of substrate

reac

tio

n r

ate

As concentration increases…

Re

act

ion

s in

crea

se…

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) Too HOT!

denature protein = unfold = lose shape Too COLD!

molecules move s l o w e r decrease collisions

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Optimum Temperature

Enzyme Activity

Tem

per

atu

re

37oC (98.6oF)

What is the optimum temperature for this enzyme?Explain what is happening?

Effect on rates of enzyme activity pH changes protein shape most human enzymes = pH 6-8

depends on where in body pepsin (stomach) = pH 3 trypsin (small intestines) = pH 8

buffers adjust pH to keep it normal

pH Affects Enzymes!

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7

pH

pH

reac

tio

n r

ate

20 1 3 4 5 6 8 9 10

stomachpepsin

intestinestrypsin

11 12 13 14

For enzymes…What matters?

SHAPE!

Enzymeshttp://www.phschool.com/

science/biology_place/labbench/lab2/concepts.html

www.andysmithart.com

Any

Que

stio

ns?

Assignment:Coach Book L11Study Island Lesson 3c

Cap

tain

En

zym

e!