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Division Ave High School Ms. Foglia REGENTS Biology

Regents Biology 2009-2010

Enzymes: “Helper” Protein molecules

Regents Biology

Flow of energy through life §  Life is built on chemical reactions

Regents Biology

I. Chemical reactions of life § Processes of life

u building molecules §  synthesis

u breaking down molecules §  digestion

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Regents Biology

Nothing works without enzymes! § How important are enzymes?

u all chemical reactions in living organisms require enzymes to work §  building molecules

w synthesis enzymes

§  breaking down molecules w digestive enzymes

u enzymes speed up reactions §  “catalysts”

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enzyme

enzyme We can’t live

without enzymes!

Regents Biology

Examples §  synthesis

§  digestion

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enzyme

enzyme

Regents Biology

II. Enzymes are proteins § Each enzyme is the specific helper to

a specific reaction u each enzyme needs to be the right shape

for the job u enzymes are named for the reaction

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

Oh, I get it! They end in -ase

Regents Biology

Enzymes aren’t used up § Enzymes are not changed by the reaction

u used only temporarily u  re-used again for the same reaction with

other molecules u very little enzyme needed to help in many

reactions

enzyme

substrate product

active site

Regents Biology

III. It’s shape that matters! §  Lock & Key model

u shape of protein allows enzyme & substrate to fit

u specific enzyme for each specific reaction

Regents Biology

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Division Ave High School Ms. Foglia REGENTS Biology

Regents Biology

Enzyme vocabulary § Enzyme

u helper protein molecule § Substrate

u molecule that enzymes work on § Products

u what the enzyme helps produce from the reaction

§ Active site u part of enzyme

that substrate molecule fits into

Regents Biology

V. What affects enzyme action § Correct protein structure

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

§  Temperature u why? enzyme has to be right shape

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

Regents Biology

Order of amino acids § Wrong order = wrong shape = can’t do its

job!

DNA

DNA

chain of amino acids

chain of amino acids

folded protein

folded protein

right shape!

wrong shape!

Regents Biology

VI. Temperature §  Effect on rates of enzyme activity

u Optimum temperature § greatest number of collisions between

enzyme & substrate § human enzymes

w 35°- 40°C (body temp = 37°C) u Raise temperature (boiling)

§ denature protein = unfold = lose shape u Lower temperature T°

§ molecules move slower § fewer collisions between enzyme &

substrate Regents Biology

37°

Temperature

temperature re

actio

n ra

te

What’s happening

here?!

human enzymes

Regents Biology

How do cold-blooded creatures do it?

Regents Biology

VII. pH § Effect on rates of enzyme activity

u changes in pH changes protein shape u most human enzymes = pH 6-8

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

Regents Biology

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pH

pH

reac

tion

rate

2 0 1 3 4 5 6 8 9 10

stomach pepsin

intestines trypsin

What’s happening

here?!

11 12 13 14

Regents Biology

Real Life Connections § What is lactose intolerance?

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Division Ave High School Ms. Foglia REGENTS Biology

Regents Biology

Why do we get uncomfortable symptoms with lactose intolerance?

Regents Biology 2009-2010

For enzymes… What matters?

SHAPE!

Regents Biology

Review Questions: § What is the function of enzymes?

§ What factors influence the functionality of enzymes?

§ Would amylase work on breaking down lipids? Why or why not?

Regents Biology 2009-2010

Let’s build some

Enzyme Models!