Bell RingerO Answer the following questions in your

notebook pg 50.O 1. Identify the following macromolecules. a. b.

• Discuss the type of bond for each and the process by which this occurs.

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Enzymes

What is an enzyme?O Proteins that act as biological

catalysts. All chemical reactions in your body require enzymes

Definitions associated with enzymes

O Catalyst - A substance that speeds up a chemical reaction

O Substrate - reactants in the enzymatic reaction, this is what an enzyme attaches to

Why are enzymes important?

O Chemical reactions take a long time to happen OR require too much energy.

O Enzymes help speed up the time it takes for reactions to happen OR allow the reaction to happen without using up too much energy

What is activation energy?

O In chemical reactions, energy is either released or absorbed.

O In order to get the chemical reaction started, it requires a certain amount of “Activation Energy”

Graph of energy of activation

Discuss in your notesO Observe the information presented

in the graphO What do you observe about the

energy of reactants with enzymes compared to without enzymes?

How do enzymes speed up chemical reactions?1. Chemical compounds attach to the

ACTIVE SITE of an enzymes2. The SUBSTRATE are the specific

substances that can bind to enzymes3. Enzymes hold the substrate in place

so the chemical reaction can happen4. After reaction is finished, enzyme

releases the PRODUCTS and helps another substrate.

Do enzymes need a specific environment?

O YESO They are sensitive to pH (acidity) and

temperature

O Human body is 37 C so most enzymes function best at this temperature

O Different organs have different pH (like the stomach) so enzymes “adapt” to their specific environments

What happens to enzymes out of their preferred

environments?O Enzymes can be denatured - they

change shape so much that they are no longer effective.

O High temp or pH can cause this to occur

Factors Affecting Enzymatic Speed1. Substrate concentration2. Temperature & pH *3. Enzyme concentration

 

Enzymatic Inhibition - when a substance binds to an enzyme and decreases its activity. (Usually reversible)

TYPES OF INHIBITION:Competitive inhibition & noncompetitive inhibition

Some inhibitors are NOT reversible - poisons like cyanide, lead poisoning all affect enzymes

QUESTION: What type of inhibition is pictured below?

Write in your journal/notes…

O Describe what is happening in each phase of this picture.

How do we name enzymes?

O They are named for the reaction the catalyze and have the suffix –ase attached to the end

O Ex. Lipase – breaks down lipidsO Protease – breaks down proteinsO Amylase – breaks down starch or

amylumO Lactase – breaks down lactose (milk

sugar)

Properties of Enzymes: NEED TO KNOW!• Enzymes are made of

proteins.

• They speed up chemical reactions inside the cytoplasm.

• They are needed only in small amounts

• They remain unchanged after each reaction and can therefore be reused

• Each enzyme is specific for a substrate

Write the following questions and answers in your notes.1. Why are enzymes necessary for

life?

2. What is the active site of an enzyme?

3. How do enzymes catalyze chemical reactions?