enzymes (part i)
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Enzymes (Part I)
Objectives for todayWhat are enzymes? What do they
do?Characteristic of enzymes
Overview Biological Molecules
Water and Living Organisms
Carbohydrates, Fats and Proteins
Enzymes
Lock & Key hypothesis
Mode of Action
Factors affecting enzyme
reactionsSpeed up chemicalRxnNot chemically altered at the endOf Rxn
Lowering Activation Energy
Specificity
Temperature pH
RecapFunctions of food for living
organismCarbohydrates, proteins and
lipidsCondensation and hydrolysis
How can the waffle be quickly broken down into individual glucose, lipid molecule and amino acid to provide you with energy?
Hydrolysis in the LabHowever, in laboratory, hydrolysis of complex food molecules like starch takes a long time and to speed things up, high temperature is needed to chemically break down starch molecules!
Hydrolysis in our BodySo, how is it possible that our body can break down food molecules so fast and break down in a relatively low temperature of 37˚C?
EnzymesEnzymes are biological
catalyst… 1.It has mass2.Most enzymes
are made up of proteins
3.There are thousands of different enzymes in our body each with a unique function!
Catalyst **“Substance which can alter or speed
up a chemical reaction, without itself being chemically changed at the end of the reaction”
1. Speed up chemical reaction2. Without being chemically changed
Crack the seed demonstration!Need 2 volunteersObjective is to crack 10 seeds in
1 minSee who is the faster one!
11
Can we break the glycosidic bonds?Hydrolytic reaction The break up of a disaccharide into monosaccharid is sped up by enzyme
+OH O
H
+Water
ENZYME
1 Maltose2
Glucose
Water
OH
OH
ENZYME
Water
ENZYME
OH
OH
Cut the wire
ScissorsSpeed up the cutting
process!
After cutting, still remain as a
scissors! Not altered!
Enzyme
ENZYMESpeed up the
chemical reaction! Like condensation and hydrolysis
Not chemically altered at the end of
the reaction!
Quick factsSince it is chemically unchanged
at the end of the reaction, enzymes can be used over and over again!
An enzyme which helps to break down starch can produce millions of glucose molecules in ONE second!
The Seed cracker is the catalyst!
1.Speed up chemical reaction
2.Without being chemically changed
3. Lower Activation energy
Reactants = “ You in bed in
home clothes”
6:20am
Products = “ You in school with uniform”
7:29am
Normal Day
Exam!
3. Lower Activation energy
Reactants = “ Starch + Water”
Products = “Glucose
molecules”
Without Enzyme
s
With Enzyme
s!
Activation energyActivation energy is defined as the energy needed to start a chemical reaction.
Since activation is lowered, our body can break down many biomolecules at 37˚C. No need any high temperature heating breakdown like those in labs.
Summary Enzymes
Biological Catalysts
Not chemically altered at the end of the Rxn
Can be reused many times
Speed up chemical reactions
Speed up condensation and hydrolysis
Lower activation energy of chemical Rxn
Some review questionsEnzymes are only found in living
thingsEnzymes cannot be re-used after a
chemical reaction since it has undergone chemical reactions
The activation energy is higher for a enzymatic reaction because enzymes need energy to function
Enzymes can only break things down and not build things up
Going a bit furtherWhere can enzymes be found?Can they be extracted out of the
body and still be functional?Let’s look at something more
close to our lives!
Flies! Do you know how they eat?
HWFind out what is the meaning of G6PD!
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