1. How Would You Make A Cake?
Cake mix
Mix & bake it
Yummy cake
Ingredients
Add energy
Have a complete product

2. Objectives Identify where living things get energy.
Understand how chemical reactions occur.
Identify why enzymes are important to living things.

3. Vocabulary Energy Reactant Product Activation Energy Enzyme
Active State
Substrate

4. Changing Matter
Living things are made of matter, which consists of a substance with a form.
In the case of the living, this form is always changing.
This is a constant in the natural world; that changes constantly occur.
Development
Seasons
Metabolism
Etc.

5. Changes Change usually comes in two forms: PHYSICAL
Physical change occurs when only the form or shape of the matter changes (it looks different but contains the same atoms & molecules).
CHEMICAL
Chemical change occurs when a substance changes into a different substance (the molecules & atoms change into different molecules).

6. What types of change happened here?
PHYSICAL B
CHEMCIAL

7. Energy The necessary ingredient of change is energy.
Energy is the ability to move or change matter.
Luckily, energy is all around us and exists in many forms.
It can be converted from one form to another & with enough education you can cause this conversion yourself, on purpose.

8. Forms of Energy Kinetic (Thermal Heat): Energy of motion Potential:
Energy that can be used at a later time.
Mechanical:
Energy transferred in machines
Electro-magnetic:
Electrons transferring energy
Nuclear:
Energy stored in the nucleus of atoms
Sound:
Energy in waves
Chemical:
Energy stored in bonds
Forms of Energy

9. Changing Matter: Bound by Laws
There are many other constraints on changes in the natural world = Universal Laws
Law of conservation of mass. = Matter is neither created nor destroyed in any change.
This means that any new forms of matter comes from existing matter!
Entropy = As matter changes, some energy is lost as heat to the surroundings
This means with every change some energy is lost forever, requiring refueling.
Law of conservation of energy = Energy may change from one form to another, but the total amount of energy does not change.
This means that any new type of energy comes from energy that has already been here…just in a different form.

10. Changing Matter Where does this energy come from?...
From heat…from the sun, the Earth’s core, or some other produced source (fires, etc.)
Or from bonds being broken…such as when food is broken down.
See Bonds & Energy at the end…

11. Chemical Reactions There are two participants of a reaction
Changing a substance chemically requires a chemical reaction. During this process, bonds between atoms are broken, and new ones are formed.
The bonds are usually through C to C bonds
There are two participants of a reaction
A reactant (aka substrate) is a substance that is changed in a chemical reaction
It’s all the stuff that you start with that mixes and mingles together.
A product is a new substance that is formed.
This is the stuff that you end up with after the mingling.

12. Reactants to Products
Reactants
Products
Reaction

13. Reactants to Products You will see several reactions in this course.
They are written in the same form:
Reactants  Products
The arrow means “changes to” or “forms”
Sometimes the arrow only goes one way (like from ingredients to cake) and sometimes the arrow goes both ways.
When the arrow goes both directions it shows you that the reactants and products can switch positions… that the reaction can go both ways.

14. Types of Chemical Reactions
There are numerous reactions in the body but 2 main types.
Catabolic: Breakdown
Uses the energy stored in bonds
Hydrolysis: ATP  ADP + Pi
Oxidation:
Anabolic: Building
Stores energy in bonds for later use
Dehydration: Synthesis of a polypeptide
Phosphorylation: ADP + Pi  ATP
Reduction:
Usually there’s two or more molecules in the reaction & they are often reversible

15. Building & Breaking: Forming the Macromolecules
The anabolic process for the macromolecules is called DEHYDRATION SYNTHESIS.
Water is pulled from neighboring subunits to allow a covalent bond to form between them.
Breaking down the molecules requires the reverse reaction, HYDROLYSIS.
Water is broken down and the resulting H+, OH- is used to split subunits apart.

16. Concept Check
What are the two parts of a reaction and what are they called?
Reactants & Products
How do you show a reaction?
Reactants  Products

17. Activation Energy
The processes that form and break down molecules often need a little energy help.
Activation Energy is the minimum kinetic energy required to start a chemical reaction
Going through a reaction, or going from reactants to products, can only occur under the right conditions.
The right conditions to start a reaction involve overcoming the natural repulsion between their negatively charged electron clouds.
Remember, like charges repel.

18. Reaction with the correct activation energy

19. Activation Energy: Summation
Chemical reactions can only occur when the activation energy is available and the correct atoms are aligned.
Activation Energy

20. Activation Energy: Energy of Matter
One of the universal laws, stated by Sir Isaac Newton hundreds of years ago, was that objects in motion stay in motion…
Think of activation energy like motivation.
When you are motivated to get off the couch and start chores or work out it’s like molecules getting the energy to react with each other…
The energy for reactions comes from temperature or how much movement the molecules have…its kinetics.
Sometimes this happens with stirring… = physical
Sometimes this happens with heating… = thermal

21. Activation Energy: Alignment of Matter
Alignment is the proper orientation the molecules.
Sometimes, even if enough energy is available, the product still may not form.
When the reactant particles collide, the correct atoms must be brought close together in the proper orientation.
Orientation means the correct parts of the molecules must meet up.

22. In living things, like our bodies, chemical reactions occur between large, complex biomolecules.
Biological Reactions
They are happening all the time…millions of reactions per second in every cell.
Many of these reactions require large activation energies to get the ball rolling.

23. Biological Reactions
Reactions are tracked using what’s called a reaction curve.
On the left is the reactants
On the right are the products.
X-axis is time.
Y-axis is energy.
Reactions travel from left to right in time.
Energy required or released is tracked, usually as heat absorbed or released.

24. NET ENERGY GIVEN OFF OR TAKEN AWAY
Biological Reactions
ENERGY ABSORBED
LINE SEPARATING REACTIONS THAT GIVE OFF ENERGY (RELEASES HEAT) OR TAKE ENERGY AWAY FROM SURROUNDINGS. (FEELS COLDER)
ACTIVATION
ENERGY
NET ENERGY GIVEN OFF OR TAKEN AWAY
ENERGY RELEASED

25. Biological Reactions… Enzymes
If given enough time most chemical reactions will occur spontaneously, but, in life, time is important.
Enzymes
In Essence: Enzymes help reactions happen that may not normally happen or may take too long to happen unaided.
HOW?
An enzyme is a protein that lowers the necessary activation energy of a reaction
Enzymes hold molecules close together and in the correct orientation.
By assisting in necessary biochemical reactions, enzymes help organisms maintain homeostasis.

26. Effect of Enzyme on Activation Energy

27. Enzymes
Enzymes
Each enzyme has an active site, the region where the reaction takes place.
Each different enzyme acts only on specific substrates.
The shape of the active site determines which reactants, or substrates, will bind to it.
Induced-fit Theory: Binding of the substrates causes the enzyme’s shape to change. This change causes some bonds in the substrates to break and new bonds to form.
Enzymes are not “used-up” in chemical reactions; they’re recycled.
Once the reaction takes place, the product leaves and the enzyme returns back to its original shape.

28. Enzyme Action Enzyme Right Orientation Product AB Reactant A
Wrong Orientation =
NO REACTION
Right Orientation
Product AB
Reactant A
Reactant B

29. Enzyme Action
Click to animate the image.

30. Enzymes Enzymes activity is dependent up two main factors;
Temperature and pH.
Many enzymes are proteins.
One restraint on proteins is that they are specific to an environment.
Changes in temperature and pH can change a protein’s shape.
Every cook an egg?
If an enzyme changes shape, it won’t work well.
Most enzymes need a certain range of temperatures and pH.
What important property of life ensures this?
Homeostasis
What molecule help us maintain this in our bodies?
Water

31. Enzymes Environmental Affects on Proteins. Normal Activity
NORMAL PRODUCTIVITY

32. Enzymes Environmental Affects on Proteins.
Temp & pH may change the enzyme’s activity but small changes won’t affect it that much. Large changes will though.
Enzymes
Environmental Affects on Proteins.
VERY RARELY WILL THERE BE AN AFFECT THAT INCREASES PRODUCTIVITY
NORMAL PRODUCTIVITY
TOO COLD: DOES NOT WORK NORMALLY or PRODUCES LESS

33. Enzymes
Denaturing Proteins. Changing the Enzyme’s shape by heating or cooling or by changing the pH too much.
Denaturing often destroys the enzyme’s activity.
DOES NOT WORK NORMALLY
WORKS NORMALLY

34. Denatured proteins will not form products.
Enzymes
Environmental Affects on Proteins.
NORMAL PRODUCTIVITY
Denatured = Will not work/no product formed
Denatured proteins will not form products.

35. Enzymes & Metabolism Sum of all chemical reactions in an organism.
Cells get most of the energy needed for metabolism by breaking down food molecules.
What is metabolism again?
Sum of all chemical reactions in an organism.
The release of energy from food molecules occurs in a series of reactions using many enzymes to capture energy in the form of ATP molecules.
ATP is what?
The energy transporter in the body.
The enzymes reduce the activation energy so much that only a little energy is needed to start the reactions. In this process, very little energy is lost as heat.

36. Concept Check Where is the active site? Where are the reactants? A B C
What is Activation Energy?
The energy necessary to start a reaction.
How are enzymes useful?
They lower activation energy to allow chemical reactions to occur by aligning the specific reactants.
Where is the active site?
Where are the reactants? A B C

37. Closure
Any Questions?
Reflect in your warm ups 1 thing you learned today!

38. Classwork/Homework.
Classwork: Work together and complete the “Polar Enzymes Skills Worksheet”
Ask questions if needed.
Homework: Lactaid Case study. Complete and have ready Monday.

39. Case Study
Some people cannot digest certain foods. For example, diabetics cannot digest sugars properly and those that are lactose-intolerant cannot digest milk. Science has been working tirelessly to help solve these problems but one can’t be too sure if the drug companies are honest.
A certain company claims that their drug will help you digest carbohydrates better (like those to combat lactose-intolerance).
You suspect the active ingredient in the product is an enzyme…lactase.
In an attempt to prove the product’s claim you perform an experiment.
Your experiment involves 3 individuals; 1 individual with lactose intolerance and consuming milk, 1 person with normal lactose tolerance consuming milk, and 1 lactose intolerant individual consuming milk & the enzyme. You need to analyze the results.
Digestive Enzyme

40. Chemical Reactions Analyze the illustration of experimental data that tests whether a digestive enzyme supplement works. In-class/Homework Questions: Answer these questions. Due:_______ Pts:_____/25
Sick/Intolerant
Healthy/Tolerant
What do the curved arrows represent?
What does the dotted line represent?
What part of a reaction is A?
What are B & C?
Describe which reaction is which?
How do the 2nd and 3rd reactions differ?
Which reaction (2 or 3) would you think uses an enzyme?
What does the enzyme do?
Which reaction gives off heat to the environment? (remember conservation of energy)
Extra Credit***: Explain what this experiment did. What are both ‘A’ & ‘C’?

41. What do the curved arrows represent?
1. The curved lines represent reactions over time.
2. The difference between taking or giving heat in the reaction, but the line represents time.
3. A: Reactant
4. B & C: Products
5. AC in lactose intolerant, AB is digesting lactose, 3 is with the enzyme
6. 3 has less activation energy.
7. Reaction 3 uses the enzyme because of the lowered activation energy.
8. Lowers the activation energy and can speed up reactions.
9. Reactions AB (2 & 3).
10. This reaction shows how lactose can be digested in those lactose intolerant. C is the control lactose intolerant. A is the normal lactose digestion.
What do the curved arrows represent?
2. What does the dotted line represent?
3. What part of a reaction is A?
4. What are B & C?
5. Describe which reaction is which.
6. How do the 2nd and 3rd reactions differ?
7. Which reaction (2 or 3) would you think uses an enzyme?
8. What does the enzyme do?
9. Which reaction gives off heat to the environment?
10. Explain what this experiment did. What are both ‘A’ & ‘C’?

42. Chapter 3 Review: Answers
3. (Reactant = substrate)  product
4. Cohesion = attraction between like particles.
Adhesion = attraction between different particles
5. Nucleic acids are made of nucleotides
6. D
7. D
8. B
9. C
10. A
11. B
12. C
13. D
14. B
15. Forming compounds can make atoms more stable b/c an atom is more stable when the valence shell is filled.
16. Adhesion and cohesion are responsible for water being able to climb up a plant stem.
17. Simple carbs have 1-2 sugar, complex have more than 2
18. Waxes are waterproof and can form protective coatings
19. Physical changes the way something looks, chemical changes the substance
20.In order for a reaction to occur, molecules must both be in the correct orientation and overcome the repulsion of like particles.
21. pH 3
22. The stomach is more acidic then the intestines.
23. There are only one type of atom in any single element.
24. They are more stable when they are covalently bonded together. They are molecules but not compounds b/c there is only one element
25. Ionic bonds are between ions that swap electrons where covalent is between atoms that share them.
26. The freezing point is dependent upon the H-bonds in water. Ions of salt disrupt them and the freezing point of water.
27. Balanced diets give you enough of the essential materials for life.

43. Identifying an Enzyme, Word Usage
Breaking a word down
In science, one can easily be confused in trying to find out what a molecule is or what it does
Luckily scientists are smart people and developed patterns to be able to identify the type of word you are reading and what it may do.
Remember:
-ose = sugar (Lactose, glucose),
-ol, -oid = lipid (cholesterol, glycerol)

44. Biological Reactions, continued
Enzymes:
An easy way to tell if a molecule is an enzyme is by the suffix.
Suffix is the word ending
Enzymes start with what they do and usually end in –ase
Protease: Breaks down proteins
Lactase: Breaks down lactose to glucose & galactose
Lipase: Breaks down _____?

45. Summary
Living things use different chemical reactions to get the energy needed for life processes.
An activation energy is needed to start a chemical reaction. The reactants must also be aligned to form the product.
By assisting in necessary biochemical reactions, enzymes help organisms maintain homeostasis.

46. With every change, really called a reaction, the total amount of usable energy decreases because some energy is given off to the surroundings as heat.
Entropy
& Living things get the energy needed for life processes through different chemical reactions that happen inside of the body.
Bonds & Energy
Energy is chemically stored in bonds of molecules and released when the bonds are broken.