chapter 4 - enzymes

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ENZYMES

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Page 1: Chapter 4 - Enzymes

ENZYMES

Page 2: Chapter 4 - Enzymes

LIVER

catalase

+ H2O2

H2O + O2

Page 3: Chapter 4 - Enzymes

ARE ENZYMES IMPORTANT

?!?

Page 4: Chapter 4 - Enzymes

IMPORTANCE OF ENZYMES Majority of reactions in living

organisms are enzyme controlled Fatal damage e.g. toxins buildup, food

cannot be absorbed

Page 5: Chapter 4 - Enzymes

WHAT ARE ENZYMES?

A biological catalyst which can alter or speed up a chemical reaction, without itself being chemically changed at the end of the reaction.

Page 6: Chapter 4 - Enzymes

ENZYME SOURCES BACTERIA

FUNGI

PLANTS ANIMALS

Page 7: Chapter 4 - Enzymes

WHAT ARE ENZYMES MADE OF? PROTEIN

all enzymes are made of proteinBUT not all proteins are enzymes

Page 8: Chapter 4 - Enzymes

SUBSTRATE SUBSTRATE = substance on

which enzymes act

E.g. starch, proteins, fats etc

Page 9: Chapter 4 - Enzymes

CLASSIFICATION According to the chemical reactions

they catalyze.

ENZYMES SUBSTRATEcarbohydratecelluloseproteinlipidsstarch

CARBOHYDRASECELLULASEPROTEASE

LIPASEAMYLASE

CARBOHYDRASECELLULASEPROTEASE

LIPASEAMYLASE

Page 10: Chapter 4 - Enzymes

WHY MUST FOOD BE DIGESTED? too large cannot be absorbed by body cells DIGESTION:

Large, insoluble food molecules broken down into small, soluble & diffusible molecules

Page 11: Chapter 4 - Enzymes

USES OF ENZYMES BREAKDOWN

e.g.glucose …. Carbon dioxide + water

SYNTHESISe.g. amino acids….proteins

Page 12: Chapter 4 - Enzymes

CHARACTERISTICS1. ALTER OR SPEED UP RATE OF

REACTION

Page 13: Chapter 4 - Enzymes

CHARACTERISTICS2. VERY POTENT Remain unchanged Can be reused A small amount for

a large amount of chemical reactions

Page 14: Chapter 4 - Enzymes

CHARACTERISTICS3. SPECIFICe.g. amylase only act on starche.g. protease only act on protein

Page 15: Chapter 4 - Enzymes

CHARACTERISTICS4. REVERSIBLE REACTIONS

A + B C + D

Page 16: Chapter 4 - Enzymes

ENZYME ACTIVE SITE = a position on the

enzyme where the substrate binds

Page 17: Chapter 4 - Enzymes

HOW DO ENZYMES WORK?

THE LOCK AND KEY HYPOTHESIS

Page 18: Chapter 4 - Enzymes

HOW DO ENZYMES WORK? SPECIFICITY Due to SHAPE

After substrate fits in,enzyme alters shape slightly

ACTIVE SITE

Page 19: Chapter 4 - Enzymes
Page 20: Chapter 4 - Enzymes

APPLICATIONS

Page 21: Chapter 4 - Enzymes

DETERGENT

Page 22: Chapter 4 - Enzymes

FRUIT JUICE

pectinase

Page 23: Chapter 4 - Enzymes

PAPAYAPAWPAW

papain

MEAT TENDERIZER

Page 24: Chapter 4 - Enzymes

oil spills

Page 25: Chapter 4 - Enzymes

FACTORS AFFECTING ENZYME ACTIVITY1. TEMPERATURE

inactive

most active

denaturedEn

zym

e a

cti

vit

y

Temperature

OPTIMUM TEMPERATURE

Page 26: Chapter 4 - Enzymes

DENATURATION

Shape changed 3D structure lost ACTIVE SITE altered

IRREVERSIBLE DESTRUCTION: extreme heat

High temperature, acids & alkalis

Page 27: Chapter 4 - Enzymes
Page 28: Chapter 4 - Enzymes

FACTORS AFFECTING ENZYME ACTIVITY2. pH most

active

denaturedOPTIMUM pH

En

zym

e a

cti

vit

y

pHdenatured

Page 29: Chapter 4 - Enzymes

FACTORS AFFECTING ENZYME ACTIVITY

3. SUBSTRATE & ENZYME CONCENTRATION

En

zym

e a

cti

vit

y

Substrate concentration

X

Y

Enzyme concentration A

Enzyme concentration B

Page 30: Chapter 4 - Enzymes

LIMITING FACTOR Directly affects rate of reaction if

quantity is changed

Page 31: Chapter 4 - Enzymes

COENZYMES Some enzymes require

coenzymes NON-PROTEIN organic

compounds Most are vitamins (B complex vitamins)

Page 32: Chapter 4 - Enzymes

THE END