Lesson 3 Enzymes and Chemical Digestion Bio 30S

B11-2-05 Explain the role of enzymes in the chemical digestion of nutrients and identify factors that influence their action.

Ask students to do the following before they get this handout.

1. Briefly research what enzymes are.

Enzymes break down food and other materials into small particles. Enzymes are built of proteins folded into complicated shapes Our metabolism relies on the work that enzymes carry out. Enzymes speed up (catalyze) chemical reactions

2. Why do we need enzymes? What do they do?

They allow chemical reactions that we need to survive to happen faster. Without enzymes, these reactions would occur too slowly to sustain life. Enzymes lower the amount of activation energy required to get these reactions started.

3. Briefly research hydrolysis.

From Ancient Greek: hydro-, meaning 'water', and lysis, meaning 'to unbind'

Any chemical reaction in which a molecule of water ruptures one or more chemical

bonds.

Do an Enzyme Demo - Jello and pineapple?

WHAT ARE ENZYMES?

Enzymes are made up of proteins, - long chains of amino acids that act as a catalyst (increases the

rates of chemical reactions).

Most enzymes contain between 100 and 1000 amino acids, which are joined together in a long chain

folded to produce a unique 3D structure.

Enzymes break apart large food molecules by hydrolysis – which is the addition of water.

WHAT DO ENZYMES DO?

Enzymes control chemical reactions in our cells

The body performs millions of chemical reactions every minute of every day. Without the “encouragement” of enzymes, these reactions would occur too slowly to sustain life.

Enzymes LOWER the amount of activation energy needed to get these reactions started.

Watch video on Enzymes and Activation Energy (2 min): https://www.youtube.com/watch?

v=ueup2PTkFW8

WHY ARE ENZYMES SO SPECIFIC?

Each enzyme is specific to a substrate and can be used over and over again.

The molecules at the beginning of the reaction, called substrates, are converted to different molecules, called products.

Watch Amoeba Sisters Enzymes (6 min): https://www.youtube.com/watch?v=qgVFkRn8f10

Has an accompanying worksheet and answer key

Watch video on Hydrolysis & Dehydration Synthesis (2 min):

https://www.youtube.com/watch?v=ZMTeqZLXBSo

Watch video on Enzymes: The Induced Fit Model (2 min): https://www.bing.com/videos/search?q=induced+fit+model&view=detail&mid=F70013072525175962D1F70013072525175962D1&FORM=VIRE

Enzymes are very specific about which reactions they catalyze.

Only molecules with exactly the right shape will bind to the enzyme and react.

These are the reactant, or substrate, molecules.

The part of the enzyme to which the reactant binds is called the active site.

This is a very specific shape and the most important part of the enzyme.

What happens at the active site? In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site.

The enzyme is the lock and the substrate is the key.

The Lock & Key Theory of Enzymes Action

Note the importance of shape, known as “enzyme specificity”

At the end of the chemical reaction, does:

a) The substrate look like it has changed? Yes/No?

b) What about the enzyme? Yes/No?

For some enzymes the complexity of the binding sites can be very precise, allowing only a single kind of substrate to bind to it.

Some other enzymes have lower specificity and will accept a wide range of substrates of the same general type.

Ex. Lipases break up any fatty acid chain length of lipid). This is because the enzyme is specific for the type of chemical bond involved and not an exact substrate.

INDUCED-FIT MODEL

When the shape of the enzyme changes when the substrate fits into it.

COFACTORS, COENZYMES, & INHIBITORS

A coenzyme is a substance that works with an enzyme to initiate or aid the function of

the enzyme.

It can be considered a helper molecule for a biochemical reaction.

Coenzymes cannot function on their own and require the presence of an enzyme.

Some enzymes require several coenzymes and cofactors.

Coenzyme Examples

The B vitamins serve as coenzymes essential for enzymes to form fats, carbohydrates, and proteins.

Main Difference – Coenzyme vs Cofactor

A unique set of biochemical reactions occurring in a particular cell defines the identity of that cell among the other cells. Enzymes are proteins that catalyze those biochemical reactions. Both coenzymes and cofactors are small, non-protein substances that play a vital role in the metabolic functions of the cell by helping the enzymes to catalyze the biochemical reactions. They bind to the active site of the enzyme. The main difference between coenzyme and cofactor is that coenzyme is a

type of cofactor that loosely binds to the enzyme whereas cofactor sometimes binds tightly to the enzyme.

INHIBITORS

A substance which slows down or prevents a particular chemical reaction or other

process, or which reduces the activity of a particular reactant, catalyst, or enzyme.

Watch video on Enzyme Cofactors & Inhibitors (4 min): https://www.youtube.com/watch?v=2rV8vty5UF8

FACTORS AFFECTING ENZYMES The rate of enzyme–catalyzed reactions depends on several factors:

pH level

Temperature

Concentration of the substrate

Concentration of the enzyme

Inhibitors

pH & Temperature

Enzymes function best at specific temperatures and pH levels.

Extreme heat causes the enzyme to lose its shape, denaturing it, and rendering it ineffective.

EXIT SLIP:

1. What are enzymes made of?

Proteins

2. What do they do?

Catalyze reactions (speed up)

3. How do they do it?

Decreasing the amount of activation energy required for the chemical reaction to occur

4. What factors affect the effectiveness of an enzyme?

pH, temperature, concentration of substrate, concentration of enzyme

5. Label the following on the diagram below:

Substrate Active Site Enzyme Products

Lesson 3 Enzymes and Chemical Digestion Bio 30S

B11-2-05 Explain the role of enzymes in the chemical digestion of nutrients and identify factors that influence their action.

Ask students to do the following before they get this handout.

1. Briefly research what enzymes are.

2. Why do we need enzymes? What do they do?

3. Briefly research hydrolysis.

WHAT ARE ENZYMES?

Enzymes are made up of _______________, long chains of ________ ________ that act as a

_________________ (increases the rates of ________________ _______________________).

Most enzymes contain between 100 and 1000 amino acids, which are joined together in a long chain

folded to produce a unique 3D structure.

Enzymes break apart large food molecules by hydrolysis – which is the addition of _______________.

WHAT DO ENZYMES DO?

Enzymes control ________________ ____________ in our cells

The body performs millions of chemical reactions every minute of every day. Without the “encouragement” of enzymes, these reactions would occur too slowly to sustain life.

Enzymes _______________ the amount of __________________ ______________ needed to get these reactions started.

Watch video on Enzymes and Activation Energy (2 min): https://www.youtube.com/watch?

v=ueup2PTkFW8

WHY ARE ENZYMES SO SPECIFIC?

Each enzyme is ____________ to a ________________ and can be

_________________________________________

The molecules at the beginning of the reaction, called _________________, are

converted to different molecules, called ____________________.

Watch Amoeba Sisters Enzymes (6 min): https://www.youtube.com/watch?v=qgVFkRn8f10

Has an accompanying worksheet and answer key

Watch video on Hydrolysis & Dehydration Synthesis (2 min):

https://www.youtube.com/watch?v=ZMTeqZLXBSo

Watch video on Enzymes: The Induced Fit Model (2 min): https://www.bing.com/videos/search?q=induced+fit+model&view=detail&mid=F70013072525175962D1F70013072525175962D1&FORM=VIRE

Enzymes are very specific about which reactions they catalyze.

Only molecules with exactly the right ____________ will bind to the enzyme and react.

These are the reactant, or ______________________, molecules.

The part of the enzyme to which the reactant binds is called the ______________ _________.

This is a very specific shape and the most important part of the enzyme.

What happens at the active site? In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site.

The enzyme is the _____________ and the substrate is the ____________.

The Lock & Key Theory of Enzymes Action

Note the importance of shape, known as

“____________ __________________”

At the end of the chemical reaction, does:

a) The substrate look like it has changed? Yes/No?

b) What about the enzyme? Yes/No?

For some enzymes the complexity of the binding sites can be very precise, allowing

only a single kind of substrate to bind to it.

Some other enzymes have lower __________________________ and will accept a

wide __________________ of substrates of the same general type.

Ex. Lipases break up any fatty acid chain length of lipid). This is because the enzyme is specific for the type of chemical bond involved and not an exact substrate.

INDUCED-FIT MODEL

When the shape of the enzyme ___________________ when the substrate fits into it.

COFACTORS, COENZYMES, & INHIBITORS

A coenzyme is a substance that works with an ___________________ to initiate or aid the function of the enzyme.

It can be considered a __________________ molecule for a biochemical reaction.

Coenzymes _______________ function on their own and require the presence of an

___________________.

Some enzymes require several coenzymes and cofactors.

Coenzyme Examples

The B vitamins serve as coenzymes essential for enzymes to form fats, carbohydrates, and proteins.

Main Difference – Coenzyme vs Cofactor

A unique set of biochemical reactions occurring in a particular cell defines the identity of that cell among the other cells. Enzymes are ________________ that _________________ those biochemical reactions. Both coenzymes and cofactors are small, _________________________ substances that play a vital role in the ____________________ functions of the cell by helping the enzymes to catalyze the biochemical reactions. They bind to the _____________ _________ of the enzyme. The main difference between coenzyme and cofactor is that coenzyme is a type of cofactor

that ________________ binds to the enzyme whereas cofactor sometimes binds ______________ to the enzyme.

INHIBITORS

A substance which _____________ __________ or ________________ a particular

chemical reaction or other process, or which _______________ the ______________

of a particular reactant, catalyst, or enzyme.

Watch video on Enzyme Cofactors & Inhibitors (4 min): https://www.youtube.com/watch?v=2rV8vty5UF8

FACTORS AFFECTING ENZYMES The rate of enzyme–catalyzed reactions depends on several factors:

________________________

________________________

________________________

________________________

pH & Temperature

Enzymes function best at specific ____________________ and ________________.

Extreme heat causes the enzyme to lose its _____________, ___________________ it,

and rendering it ________________________.

EXIT SLIP:

1. What are enzymes made of?

2. What do they do?

3. How do they do it?

4. What factors affect the effectiveness of an enzyme?

5. Label the following on the diagram below:

Substrate Active Site Enzyme Products