1. EXOTHERMIC ENERGY TIME
Draw in notes:
Chemical Reactions
EXOTHERMIC
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
PRODUCTS
START
END
TIME

2. ENDOTHERMIC ENERGY TIME
Draw in notes:
Chemical Reactions
ENDOTHERMIC
PRODUCTS
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
START
END
TIME

3. EXOTHERMIC ENERGY TIME
Every reaction – even exothermic ones – must absorb some energy to get started.
Chemical Reactions
EXOTHERMIC
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
ENERGY RELEASED
PRODUCTS
START
END
TIME

4. ENDOTHERMIC ENERGY TIMEq
ENDOTHERMIC
Chemical Reactions
ENERGY ABSORBED
PRODUCTS
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
START
END
TIME

5. The amount of energy needed to start a reaction is called the activation energy.
Chemical Reactions
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.

6. Activation Energy The amount of energy needed to start a reaction.
A chemical reaction is a process that changes one set of chemicals into another set of chemicals. The coke/mentos explosion is a type of chemical reaction.
The amount of energy needed to start a reaction.

7. EXOTHERMIC ENERGY TIME
The amount of energy needed to start a reaction is called the activation energy.
Chemical Reactions
EXOTHERMIC
MORE
Low A.E.
A.E.
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
ENERGY RELEASED
PRODUCTS
LESS
START
END
TIME

8. ENDOTHERMIC ENERGY TIMEdd
ENDOTHERMIC
Chemical Reactions
ENERGY ABSORBED
MORE
PRODUCTS
A.E.
High A.E.
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
LESS
START
END
TIME

9. Chemical Reactions Fuck off Exothermic Endothermic Photosynthesis
Energy absorbed
Energy released
Exothermic
Endothermic
(More common in living things)
Photosynthesis
Burning glucose
Breakdown of starch
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
Low A.E.
High A.E.
Copyright Pearson Prentice Hall

10. Based on the graphs, which reaction is harder to start –exothermic or endothermic?
Chemical Reactions
EXOTHERMIC
ENDOTHERMIC
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
Harder to start
High A.E.

11. Based on the graphs, which reaction is slower – exothermic or endothermic?
Chemical Reactions
EXOTHERMIC
ENDOTHERMIC
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
Slower
High A.E.

12. Endothermic reactions are difficult to start and occur slowly because they have high A.E.
Chemical Reactions
ENERGY ABSORBED
MORE
PRODUCTS
A.E.
ENERGY
REACTANTS
Other reactions occur quickly. For example, when something is burned, the reaction is rapid and sometimes explosive. LIGHT CANDLE. But what exactly does it mean to “burn” something? Like rusting, burning means combining material with oxygen. When I burn the candle, I am combining it with oxygen. PLACE GLASS OVER CANDLE. This is why a flame will go out if it doesn’t get any air – it needs oxygen to burn. However, unlike rusting, when something is burned, it reacts with oxygen very rapidly. Burning also happens in our bodies. We eat food and breath in oxygen. We burn the food by combining it with oxygen . But how is the burning reaction in our bodies different from burning a candle? Our bodies can control the rate of the reaction so that we don’t burn up our food all at once. Instead, we burn it slowly. Our 98.6 degree body heat is a result of this slow burn.
LESS
START
END
TIME

13. These reactions are made possible by enzymes.
REMEMBER - DON’T SWALLOW. So, what is a catalyst? A catalyst is a substance that starts or speeds up a chemical reaction. Catalysts work by lowering a reaction’s activation energy. What is activation energy? The amount of energy needed to start a reaction. BOOK DEMO. Remember, this book will not fall off the desk by itself. In order to make it fall, I have to push it. In other words, I have to overcome the activation energy. A catalyst makes this process a lot easier by lowering the activation energy of the reaction. BOOK/WEDGE DEMO.

14. Enzyme A protein that catalyzes chemical reactions by lowering the AE.
A chemical reaction is a process that changes one set of chemicals into another set of chemicals. The coke/mentos explosion is a type of chemical reaction.
A protein that catalyzes chemical reactions by lowering the AE.
Speeds up

15. Enzyme-catalyzed reaction
Enzymes
Enzyme-catalyzed reaction
MORE
A.E.
High A.E.
ENERGY
PASS OUT BREAD, CHEW IT, AND KEEP IT IN YOUR MOUTH. DON’T SWALLOW! Yesterday, we talked about chemical reactions. As you know, some chemical reactions occur spontaneously and have low activation energies. These reactions will happen all by themselves. But many chemical reactions that make life possible are too slow or have activation energies that are too high to make them practical for living tissue. For example, the bread in your mouth contains starch. Although starch contains lots of energy, our bodies can’t use starch directly. We can only use glucose. Is there glucose in starch? Yes! Starch is made from glucose monomers. Unfortunately, starch won’t break down into glucose on its own. Even if we chewed for hours, the high activation energy of this reaction would prevent it from occurring spontaneously. This type of chemical reaction is made possible by a catalyst, which we will learn about today. If you want to experience the effect of a catalyst on this reaction, don’t swallow the bread.
LESS
START
TIME
END

16. Reactant Enzyme Products Lowers the A.E. Products released
REMEMBER - DON’T SWALLOW. So, what is a catalyst? A catalyst is a substance that starts or speeds up a chemical reaction. Catalysts work by lowering a reaction’s activation energy. What is activation energy? The amount of energy needed to start a reaction. BOOK DEMO. Remember, this book will not fall off the desk by itself. In order to make it fall, I have to push it. In other words, I have to overcome the activation energy. A catalyst makes this process a lot easier by lowering the activation energy of the reaction. BOOK/WEDGE DEMO.
Products released

17. Enzymes lower A.E. by holding the reactant(s) in place, making it easier for the reaction to occur.
REMEMBER - DON’T SWALLOW. So, what is a catalyst? A catalyst is a substance that starts or speeds up a chemical reaction. Catalysts work by lowering a reaction’s activation energy. What is activation energy? The amount of energy needed to start a reaction. BOOK DEMO. Remember, this book will not fall off the desk by itself. In order to make it fall, I have to push it. In other words, I have to overcome the activation energy. A catalyst makes this process a lot easier by lowering the activation energy of the reaction. BOOK/WEDGE DEMO.
Products
Lowers the A.E.
Products released

18. When the reaction is complete, the products are released, and the enzyme is free to start the process again.
Enzymes
Reactant
Enzyme
REMEMBER - DON’T SWALLOW. So, what is a catalyst? A catalyst is a substance that starts or speeds up a chemical reaction. Catalysts work by lowering a reaction’s activation energy. What is activation energy? The amount of energy needed to start a reaction. BOOK DEMO. Remember, this book will not fall off the desk by itself. In order to make it fall, I have to push it. In other words, I have to overcome the activation energy. A catalyst makes this process a lot easier by lowering the activation energy of the reaction. BOOK/WEDGE DEMO.
Products
Lowers the A.E.
Products released

19. Since enzymes can be reused, it only takes a few enzymes to convert a large number of reactants into products.
Enzyme Action
ENZYME VIDEO. So, enzymes are used over and over again. They’re recycled. After an enzyme acts upon one molecule of substrate, it moves onto the next molecule of substrate.

20. ENZYME-SUBSTRATE COMPLEX
The reactant in an enzyme-catalyzed reaction is called the substrate.
Enzymes
Endothermic reaction
High A.E.
SUBSTRATE
Reactant
ENZYME-SUBSTRATE COMPLEX
Enzyme
REMEMBER - DON’T SWALLOW. So, what is a catalyst? A catalyst is a substance that starts or speeds up a chemical reaction. Catalysts work by lowering a reaction’s activation energy. What is activation energy? The amount of energy needed to start a reaction. BOOK DEMO. Remember, this book will not fall off the desk by itself. In order to make it fall, I have to push it. In other words, I have to overcome the activation energy. A catalyst makes this process a lot easier by lowering the activation energy of the reaction. BOOK/WEDGE DEMO.
Products
Lowers the A.E.
Products released

21. The fit between an enzyme and a substrate is very precise (like a lock and key).
DON’T SWALLOW. Enzymes are very specific, generally catalyzing only one chemical reaction. For this reason, part of an enzyme’s name is usually derived from the reaction it catalyzes. The starch in your mouth is called amylose. The enzyme that breaks it down is called amylase. There are lots of enzymes in your body, but only amylase can break down amylose.

22. STARCH Lowers the A.E. GLUCOSE
DO YOU TASTE SWEETNESS IN YOUR MOUTH YET? The amylose is being broken down into glucose by the amylase. Now, why can’t amylase act on any other substrates? Because it can’t fit with them. The fit between an enzyme and its substrate is so precise that the active site and substrates are often compared to a lock and key. Amylase is like a key that will open only one type of lock, the starch amylose.
GLUCOSE

23. CELLULOSE Lowers the A.E. GLUCOSE
Enzyme Action
CELLULOSE
Lowers the A.E.
DO YOU TASTE SWEETNESS IN YOUR MOUTH YET? The amylose is being broken down into glucose by the amylase. Now, why can’t amylase act on any other substrates? Because it can’t fit with them. The fit between an enzyme and its substrate is so precise that the active site and substrates are often compared to a lock and key. Amylase is like a key that will open only one type of lock, the starch amylose.
GLUCOSE

24. a
Enzyme Action
DO YOU TASTE SWEETNESS IN YOUR MOUTH YET? The amylose is being broken down into glucose by the amylase. Now, why can’t amylase act on any other substrates? Because it can’t fit with them. The fit between an enzyme and its substrate is so precise that the active site and substrates are often compared to a lock and key. Amylase is like a key that will open only one type of lock, the starch amylose.

25. a
DO YOU TASTE SWEETNESS IN YOUR MOUTH YET? The amylose is being broken down into glucose by the amylase. Now, why can’t amylase act on any other substrates? Because it can’t fit with them. The fit between an enzyme and its substrate is so precise that the active site and substrates are often compared to a lock and key. Amylase is like a key that will open only one type of lock, the starch amylose.

26. Copyright Pearson Prentice Hall
Since there are thousands of different substrates, your body must make thousands of different enzymes .
Enzyme Action
DO YOU TASTE SWEETNESS IN YOUR MOUTH YET? The amylose is being broken down into glucose by the amylase. Now, why can’t amylase act on any other substrates? Because it can’t fit with them. The fit between an enzyme and its substrate is so precise that the active site and substrates are often compared to a lock and key. Amylase is like a key that will open only one type of lock, the starch amylose.
Copyright Pearson Prentice Hall

27. Enzymes don’t work well at high temperatures.
Enzyme Action
Enzyme activity tends to increase as temperature increases. However, at very high temperatures, enzyme activity decreases and may stop completely.
Enzymes can be affected by any variable that influences a chemical reaction. What does this mean? Well, just like you study best under certain conditions, enzymes work best under certain conditions. Some enzymes work best at certain pH values. For example, the enzymes that break down food in your stomach work best in a very acidic environment (low pH). Many enzymes are affected by changes in temperature. If you raise the temperature too much, you risk damaging the enzyme by changing its shape. Then, it can no longer fit into the “lock” of its substrate. Most of the enzymes in your body work best at body temperature, 98.6 degrees F. 27

28. Enzymes are proteins. If you heat an enzyme, it changes shape
Enzymes are proteins. If you heat an enzyme, it changes shape. It will no longer be able to fit with its substrate.
Enzyme Action
Enzyme activity tends to increase as temperature increases. However, at very high temperatures, enzyme activity decreases and may stop completely.
Body temperature
Enzymes can be affected by any variable that influences a chemical reaction. What does this mean? Well, just like you study best under certain conditions, enzymes work best under certain conditions. Some enzymes work best at certain pH values. For example, the enzymes that break down food in your stomach work best in a very acidic environment (low pH). Many enzymes are affected by changes in temperature. If you raise the temperature too much, you risk damaging the enzyme by changing its shape. Then, it can no longer fit into the “lock” of its substrate. Most of the enzymes in your body work best at body temperature, 98.6 degrees F. 28

29. Enzyme work best at body temperature (98.6 ° F).
Enzymes can be affected by any variable that influences a chemical reaction. What does this mean? Well, just like you study best under certain conditions, enzymes work best under certain conditions. Some enzymes work best at certain pH values. For example, the enzymes that break down food in your stomach work best in a very acidic environment (low pH). Many enzymes are affected by changes in temperature. If you raise the temperature too much, you risk damaging the enzyme by changing its shape. Then, it can no longer fit into the “lock” of its substrate. Most of the enzymes in your body work best at body temperature, 98.6 degrees F.
Copyright Pearson Prentice Hall 29

30. A very high fever can kill you because the enzymes in your body change shape and can no longer catalyze reactions.
Enzymes can be affected by any variable that influences a chemical reaction. What does this mean? Well, just like you study best under certain conditions, enzymes work best under certain conditions. Some enzymes work best at certain pH values. For example, the enzymes that break down food in your stomach work best in a very acidic environment (low pH). Many enzymes are affected by changes in temperature. If you raise the temperature too much, you risk damaging the enzyme by changing its shape. Then, it can no longer fit into the “lock” of its substrate. Most of the enzymes in your body work best at body temperature, 98.6 degrees F. 30