Explain in your own words what a chemical reaction is.   2. Fill in the blanks: There are two parts to a chemical reaction. The starting substances also known as the _________, and the substances formed during the reaction known as the_________.

Types of Chemical Reactions Exergonic – reaction that occurs spontaneously, gives off energy, salt dissolving Endergonic – reaction that absorbs energy, does not occur spontaneously energy is required to get the reaction going

Equation for ? 6CO2 + 6H2O + sunlight  Glucose + 6O2 Set of reactions that do not occur on their own Requires many different ENZYMES What is the energy source?

Objective! Students will be able to explain the function and structure of enzymes.

Once upon a time… A woman named Jane and a man named Steve were both single and lonely, living on opposite sides of town. They each went on a lot of first dates with other singles, but never seemed to meet anyone special. Eventually, Jane and Steve both grew weary of the single life and decided to speed things up by logging on to the matchmaking site eharmony.com. Within a day eharmony.com suggested that Jane and Steve go on a date. On their first date, sparks flew. Jane and Steve soon decided to get married.

Enzymes Amino Acid many linked together to build a protein An enzyme is a protein. There are 20 different R groups each with their own unique properties. The R groups determine the shape and activity of the protein. All enzymes are proteins but not all proteins are enzymes!

Review of Protein Structure

Enzymes: 1.Enzymes are proteins that catalyze (speed up) chemical reactions. 2. Also known as biological catalysts The enzymes called synthases remove water from molecules speeding up reactions that normally wouldn’t occur quick enough for survival of the organism.

Enzymes 3. Bring chemical ingredients (substrates) together to help speed up the reaction. 4. The substrates meet, react, and change. 5. The new, changed materials are called PRODUCTS.

Activation Energy the energy needed to start a chemical reaction Lowering the activation energy is key in helping reactions take place quickly enough for the body to remain in a state of homeostasis. Enzymes lower Activation Energy

Enzymes Can be reused after each reaction not destroyed after making the products. Only work with specific substrates The surface of an enzyme has a distinct shape that allows it to interact with only certain substrates. An enzyme will fit like a puzzle piece with it’s substrate partner, but ONLY it’s partner Humans have thousands of enzymes that each have specific functions (ex. Lactase, Amylase)

The substrate binds to a location of the enzyme called the active site The substrate binds to a location of the enzyme called the active site. The active site and the substrate have complimentary shapes. An induced fit is created where the active site fits the substrate tightly; like a baseball fitting into a catcher’s mitt.

Strong forces hold the enzyme and the substrate together Strong forces hold the enzyme and the substrate together. The tightly bound structure is held together until the reaction is complete. When the reaction is done, the products are released. The enzyme remains unchanged and then waits for more substrates to bind to it to have another reaction occur.

…so what does this have to do with Jane and Steve?

Think about how Jane, Steve, and eharmony Think about how Jane, Steve, and eharmony.com might be related to enzymatic reactions. Hint:

Which piece is Jane, Steve, eharmony?

How do enzymes ACTUALLY help reactions? Living things are chemical factories driven by chemical reactions. However, these reactions occur very slowly because it takes a lot of energy to allow the reactions to take place. Enzymes lower this energy. Which requires LESS energy? Steve going on 1000 first dates until he randomly finds Jane at the grocery store in ten years Steve logging on to eharmony.com, meeting Jane within a day.

Regulation of Enzyme Activity Certain enzymes work best at a specific pH (stomach acid – pH2) Enzymes are designed to work at specific temperatures (human body temp) Controlled by other proteins that turn on or off enzyme activity VERY Well-designed systems!

Enzymes speed up reactions that could eventually happen on their own. Example: salivary amylase breaks apart starches on a molecular level – before they even leave your mouth! This saves work for your intestines by breaking food into small pieces early on

Let’s Practice! Looking at this diagram label: A, B, C

A: Active Site B: Enzyme C: Substrate

What macromolecule are enzymes made of? Proteins

What do enzymes lower in order to speed up reactions? Energy needed to start the reaction

What are the two components involved in a reaction What are the two components involved in a reaction? What are the “lock” and the “key”? Substrate and Enzyme

What is the area called where the substrate binds to the enzyme? Active Site

Do chemical reactions NEED enzymes to occur? NO! But without the help of the enzymes to speed up the reactions what would happen? Chemical reactions would occur too slowly for organisms to maintain homeostasis.

-Which letter undergoes a chemical reaction? C - substrate

which of these changes into a new substance? C - substrate

which of these is where the reaction occurs? B- Enzyme

Substrate Active site Enzyme Products releasing

Why is it important that the enzymes are able to lower activation energy? The reactions can occur much faster than they would have without the enzyme. Living organisms need reactions to occur quickly so that they can maintain “homeostasis”

WHY???????

Without enzymes, many of the chemical reactions that occur in living things would occur at rates that are much too slow for the organism to survive!

Experiencing enzymes at work! We are now going to do a mini lab on how a specific enzyme in your saliva works to break down food. You will complete the following in your notes: 1. Observations after crushing up the cracker inside your bag. 2. How did your cracker change after it was placed inside your mouth? 3. What are some observable differences between the cracker in the bag after being crushed and the cracker put inside your mouth?