Enzymes

Enzyme in our daily lives

Any other uses?

Washing Detergent

Enzyme

It is a biological catalyst….

Exam Time!!!!

Unmotivate

d Slow

Bored

Motivated

FasterInterested

Reward!!!!

Reward is the catalyst.

Catalyst

“Substance which can alter or speed up a chemical reaction, without itself being chemically changed at the end of the reaction”

Speed up chemical reaction Without being chemically changed

Catalyst

catalyst

Without Catalyst• Slow reaction• Needs a lot of energy to start reaction

With Catalyst

• Faster

• Needs less

energy to start

reaction

Example of Inorganic Catalyst Potassium Chlorate (VII) Melt during heating and produce oxygen

Reaction is slow High temperature

Add catalyst manganese (IV) oxide Reaction is faster Lower temperature No change to catalyst

at the end of the reaction.

Enzyme – Biological Catalyst

EnzymeEnzyme is like a wrench

Enzyme remains

unchanged.

Like wrench, it

can be reused

over and over

again.

Enzyme is

specificE.g. wrench can

only fit bolts of

certain sizes.

Enzyme speeds up reaction in both directions.E.g. wrench can take things apart or put them together

Enzymes

Catalyse chemical reactions in living cells

Change rate of reaction

Not chemically changed

Catalyse reaction that

Build up complex substances

Break down complex substances

Biological catalysts made of proteins

Enzymes

Clip – Enzymes are proteins

Enzymes

Clip – Enzyme activity

Denaturation of Proteins

When denatured,

Bonds within protein molecules broken

Enzyme changes its shape

Denaturation is caused by

High temperature

Change in pH

Recap

Enzyme and Digestion

Food molecules

Large

insoluble in water

Cannot diffuse through cell membrane Need to break down into simpler and smaller

molecules

Soluble in water

diffusible

Enzymes and Digestion

Enzymes and Digestion

Digestive enzymes Enzymes that help to digest food Example

Amylase: digests starch to maltose

Maltase: digests maltose to glucose

Proteases: digest proteins to amino acids

Enzyme Names

Maltose

aseProtein

sase

Characteristics of Enzymes1. Speed up chemical reactions

Lower activation energy

Characteristics of Enzymes1. Speed up chemical reactions

Definition Activation Energy: Energy required to start the reaction Reactants: Starting materials for reaction Products: End materials from reaction

Characteristics of Enzymes2. Enymes are required in small amounts

Remain unchanged Reused over and over again Hence only small amount is required

Characteristics of Enzymes2. Enzymes are specific

Each chemical reaction is catalysed by a unique enzyme

Lock and Key hypothesis

Characteristics of Enzymes2. Enzymes are specific

Characteristics of Enzymes2. Enzymes are specific

Definition Substrates: Substances enzymes act on Active Sites: “pockets” on enzymes where

specific substrates will fit

Characteristics of Enzymes Heating or change of pH will change the

shape of enzyme Active site changes shape Loses its uniqueness

Any Questions?