The Nature of Matter Name: ______________________________

Section 2.1 Date: _________________ Period: ______

Lesson Objectives

Identify the three subatomic particles found in atoms.

Explain how all of the isotopes of an element are similar and how they are different.

Explain how compounds are different from their component elements.

Lesson Summary

Atoms - The atom is the basic unit of matter, made up of three subatomic particles.

Protons have a positive charge and neutrons carry no charge. Strong forces bind protons and neutrons together in the nucleus.An electron is a negatively charged particle that has only about 1/1840 the mass of a proton. Electrons constantly move around the space surrounding the atom’s nucleus.Because an atom has the same number of protons and electrons, if it is electrically neutral.

Elements and Isotopes - A chemical element is a pure substance that consists entirely of one type of atom.

Atoms of the same element that differ in the number of neutrons are called isotopes. Isotopes are identified by their mass number, the total number of protons and neutrons in the nucleus. Because they have the same number of electrons in each atom, all isotopes of an element have the same chemical properties.Radioactive isotopes have unstable nuclei and break down at a constant rate.

Chemical Compounds - A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions. The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed. Scientists use formulas to show the ratio of elements that make up a compound.Chemical Bonds - The atoms in compounds are held together by chemical bonds. Electrons that are available to form bonds are called valence electrons.

An ionic bond forms when one or more electrons are transferred from one atom to another, forming ions. An atom that loses electrons becomes positively charged. An atom that gains electrons becomes negatively charged.A covalent bond forms when electrons are shared rather than transferred. The structure formed by atoms joined by covalent bonds is called a molecule. The molecule is the smallest unit of most compounds.When molecules are close together, a slight attraction can form between the oppositely charged portions of nearby molecules. These intermolecular forces of attraction are called van der Waals forces.

Questions:1. A chemical element is a pure substance that consists entirely of one type of .

2. Atoms of the same element that differ in the number of neutrons they contain are called

3. An atom is made up of protons, neutrons, and .

4. The nucleus, the center of the atom, is made up of __________________ and __________________.

5. The negatively charged particles in atoms are called __________________.

6. In a/an _____________________ bond, electrons are transferred between atoms.

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7. What is a chemical compound?

8. What do the formulas for table salt, NaCl, and water, H2O, indicate about these compounds?

9. What is the difference between an ionic bond and a covalent bond?

10. Explain how an atom becomes an ion.

11. Explain the difference between a cation and an anion and give an example of each.

12. What are the similarities and differences between protons and neutrons?

13. What are the similarities and differences between protons and electrons?

14. What is the relationship between atoms and molecules?

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15. Atoms are electrically .

16. If atoms lose one electron, they become _______________ charged particles or __________________ and

will have a ____________________ charge. If they lose 1 electron, the charge will be ___________and if

they lose 2 electrons, the charge will be ___________.

17. If atoms gain electron(s), they will have a ____________________ charge. If they gain 1 electron, the

charge will be _________ and if they gain 2, the charge will be ______________.

COUNTING ATOMS Name: Biology Period: Date:

Directions: Determine how many atoms of each element are present in the following compounds.

FORMULA # MOLECULES # INDIVIDUAL ATOMS # TOTAL ATOMS

2NaHCO3 2

Na: 2 x 1 = 2H: 2 x 1 = 2C: 2 x 1 = 2O: 2 x 3 = 6

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1. C2H4O2

2. Mg(OH)2

3. 3H3PO4

4. 2H2SO4

5. (NH4)3PO4

6. 4CaCO3

7. 3Ba(OH)2

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8. CH3CH2OH

9. 4Ca(ClO3)2

10. Al2(SO4)3

11. 3(NH4)2SO4

Water Molecule Kit

1) Put the water molecules together.a. What is the formula for water?b. Draw and label a molecule of water. Place a + symbol on each hydrogen and 2 – symbols on the

oxygen.

2) What will happen when two water molecules bump into each other?a. Draw 2 additional molecules of water with the molecule you drew in 1b (there should be 3

molecules of water now).b. What are the similarities and differences between magnets and water molecules?

3) Where are covalent bonds found in the model?

4) Where are hydrogen bonds found in the model?

5) What is the difference between intramolecular bonds and intermolecular forces? Think about what INTRA vs. INTER means (interstate vs. intrastate, intersection, etc.).

6) Try to break the “bond” between the water molecules by pulling them apart. Compare this to the relative strength of pulling a hydrogen atom off a water molecule.

a. What is the intermolecular that holds the two water molecules together?b. What is the intramolecular bond that holds the hydrogen atoms and oxygen atom within a water

molecule?

7) Use the sodium chloride (NaCl) – blue and green atoms – to determine how it interacts with the water molecules.

a. Will a water molecule interact with sodium chloride? Why?b. What is the intramolecular bond that holds sodium and chloride ions together?c. Are there hydrogen bonds formed between water and sodium chloride?

8) Take a look at ethane (teacher model).a. What is the formula for ethane?

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b. Do the ethane molecules “stick” together? c. Do the ethane molecules “stick” to water?d. Is a water molecule a polar covalent or a nonpolar covalent molecule?e. Is ethane a polar covalent or a nonpolar covalent molecule?f. Will ethane form a hydrogen bond with water?

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PROPERTIES OF WATER Name: Biology Date: Period:

Read the following passage and answer the questions in the space provided.

An attractive force between particles of the same kind is known as cohesion. Cohesive forces resulting from water’s hydrogen bonding are strong enough to cause water to act as if it has a thin “skin” on its surface. This is why water appears to bulge from the sides of a glass filled to the brim.

Adhesion is the attractive force between unlike substances. Together, adhesion and cohesion enable water molecules to move upward through narrow tubes against the force of gravity. This property of water is known as capillarity.

VOCABULARY REVIEW: Define the following terms.

1) polar compound

2) hydrogen bond

3) cohesion

4) adhesion

RECOGNIZING SIMILARITIES AND DIFFERENCES

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5) How are cohesion and adhesion alike?

6) How are cohesion and adhesion different?

3-1 REVIEW

TRUE or FALSE: For Questions 7-10, write True or False on the line provided. If it is false correct the underlined word.

______1.______2.______3.______4.______5.______6._____________ 1. _____________ 2. _____________ 3. _____________ 4. _____________ 5. _____________ 6. _____________ 7. Water is a polar molecule.

_____________ 8. Hydrogen bonds are an example of adhesion.

_____________ 9. Covalent bonds give water a high heat capacity.

_____________ 10. A hydrogen bond is stronger than a covalent bond.

MULTIPLE CHOICE: Circle the letter of the word or phrase that best completes the statement.

7)8)9)10)11) The thin “skin” that appears to form on water’s surface occurs because of

a. cohesion. b. adhesion. c. capillarity. d. both (a) and (b)

12) In a water molecule,a. all of the atoms have a slight positive charge.

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b. the oxygen atom has a slight negative charge and the hydrogen atoms have slight positive charge.c. the oxygen atom has a slight positive charge and the hydrogen atoms have a slight negative charge.d. all of the atoms have a slight negative charge.

13) When sodium chloride is dissolved in water, the sodium ionsa. are attracted to the oxygen atoms of water molecules.b. are attracted to the hydrogen atoms of water molecules.c. are attracted to each other.d. do not dissociate from the sodium chloride.

14) Hydrogen bondsa. form between hydrogen atoms in different molecules.b. are strong bonds.c. hold water molecules to one another.d. hold the two hydrogen atoms together in a molecule of hydrogen gas, H2.

15) When a glass is filled to the brim with water, the water appears to bulge from the sides of the glass due toa. capillarity. b. thermal energy. c. adhesion. d. cohesion.

16) When liquid water is heated, most of the energy that the water initially absorbs is used toa. raise the temperature of the water.b. break the covalent bonds between the hydrogen and oxygen atoms in water.c. make the water boil.d. break the hydrogen bonds between the water molecules.

SHORT ANSWER: Answer the questions in the space provided.

17) Why is water a good solvent?

18) What kinds of substances besides water can be involved in hydrogen bonding?

19) What property of water allows it to stick to a dry surface, such as a wooden countertop?

20) How does water help cells keep an even temperature despite temperature changes in the environment?

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21) Explain why water forms large, round drops as it falls from a faucet with a slow leak.

22) Water is often called the universal solvent because it dissolves most substances that are important to living things. What does this suggest about the nature of those substances?

STRUCTURES AND FUNCTIONS 23) The diagram below represents a single water molecule. Draw THREE other water molecules near it, and use

dashed lines to indicate where HYDROGEN bonds would form between the molecule shown below and the ones you drew.

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CLASSIFICATION Name: ________________________

Biology Date: ___________ Period: ______

Solutions and Suspensions - Complete the table

Substance Definition Example(s)

Physical combination of two or more substances Cinnamon sugar

Solute Salt in saltwater

Solvent

Mixture of water and nondissolved substance Blood

Solution

Match each of the following statements with one or more of the following forms of matter.

(E) Element (C) Compound (S) Solution (M) Heterogeneous Mixture

______ 1. Dirt

______ 2. CH3OCH3

______ 3. Perfume

______ 4. Nitrogen gas (N2)

______ 5. Air (O2, N2, CO2, Ar)

______ 6. Jell-O

______ 7. Tin

______ 8. CO2

______ 9. Pizza

______ 10. Aluminum

______ 11. Chocolate syrup

______ 12. Hot chocolate with marshmallows

______ 13. Salt (NaCl)

______ 14. Baking soda (NaHCO3)

______ 15. Mercury

______ 16. Tap water

______ 17. Distilled Water

______ 18. 14-carat gold ring

______ 19. Diamond

______ 20. Scoop of Beach Sand

______ 21. Liquid dish detergent

______ 22. Calcium

______ 23. Steam

______ 24. Raisin Bran © cereal

______ 25. Italian salad dressing

______ 26. Oxygen (O2)

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Water, Acids, and Bases Name: ____________________________________

Section 2.2 Date: _____________________ Period: _______

Water is one of the most important molecules in the body. Cells are made mostly of water and water is required for almost every metabolic reaction in the body. The force of attraction between water molecules is so strong that the oxygen atom of one molecule can actually remove the hydrogen from other water molecules. This reaction is known as dissociation, and it takes place in our cells.

Water (H2O) dissociates into H+ and OH- ions. A charged atom or molecule is called an ion. The OH- ion is called the hydroxide ion, while the H+ ion is called the hydrogen ion. Free H+ ions can react with another water molecule to form the H3O+ or hydronium ion. The human body requires a neutral pH for many reasons. One reason cells like a neutral pH is for proteins. Basic or acidic solutions denature proteins (change their shape) so they no longer work.

1. What is dissociation? _____________________________________________________________________

_______________________________________________________________________________________

2. What is the chemical formula for water? _____________________________________________________

3. What is an ion? _________________________________________________________________________

4. Name the 2 ions form when water dissociates. _________________________________________________

5. What is the hydroxide ion? _________________________________

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6. What is a hydrogen ion? _________________________________

Acidity or alkalinity is a measure of the relative amount of H+ and OH- ions dissolved in a solution. Neutral solutions have an equal number of H+ and OH- ions. Acids have more H+ ions than OH- ions.

Acids taste sour and can be corrosive. Digestive fluids in the body are acidic and must be neutralized by buffers. Bases contain more OH- ions than H+ ions. Bases taste bitter and feel slippery.

When an acid is combined with a base, neutralization occurs. The result of neutralization is a salt and water. Neutralization helps return our body pH to neutral. The process of our bodies maintaining neutral pH so that proteins can work properly without being denatured (unfolded) is known as homeostasis.

7. Acids have more _________________ ions than _________________ ions.

8. Bases contain more _________________ ions than _________________ ions.

Neutral solutions have an number of H+ and OH- ions.

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ACIDS, BASES, and pH1. What makes pure water neutral? ____________________________________________________________

2. What does the pH scale measure? ___________________________________________________________

3. On the pH scale, indicate which direction is increasingly acidic and which is increasingly basic.

4. Identify two solutions that have more H+ ions than OH– ions.

____________________________________

5. Identify two solutions that have more OH– ions than H+ ions.

____________________________________

6. Why are buffers important to living things?

______________________________________________________________________________________________

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Properties of Water Name: ______________________________

Section 2.2 Date: _________________ Period: ______

POLARITY AND HYDROGEN BONDING1. If there are 600 water molecules in a glass. What is the total number of hydrogen atoms in the glass? What

is the total number of oxygen atoms in the glass? What is the total number of atoms in the glass?

2. Include the partial charges of each atom in the water molecule to the right.

3. Why is water considered to be a polar molecule?

4. Explain why the oxygen atom in water has a negative charge.

5. Explain why the two pictures below are incorrect:

6. What is the name of the bond formed between water molecules?

7. A student in biology class accidentally spills some vegetable oil on her favorite shirt. She tries to wash the oil off of her shirt with water but she is unsuccessful. Explain why it would be impossible to remove an oil stain with just water. Please talk about polarity in your answer.

_______________________________________________________________________________________

_______________________________________________________________________________________

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The diagram shows a salt crystal (NaCl) being dissolved in water.8. In this mixture identify the solute and solvent.

9. Why are the water molecules attracted to Cl- ions and the Na+ ions in the salt?

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HEAT CAPACITY10. As a substance is heated its molecules vibrate slower / faster.

11. Since water has a very high heat capacity the ocean temperature is very stable / unstable.

12. During a hot summer day the temperature of the water heats up much faster / slower than the temperature of the air.

13. Most animals in the ocean are cold blooded which means that their body temperature is equal to the temperature of the water. What would happen to the animals living in the ocean is that ocean temperature was to rapidly change?

_______________________________________________________________________________________

_______________________________________________________________________________________

________________

STATES OF MATTER14. Does cold water (not frozen) sink or float in warmer water? Why?

15. Which state of water forms the most hydrogen bonds?

16. Which state of water forms the least hydrogen

bonds?

17. What is the temperature range where water will

remain a liquid?

18. At what temperature must you cool water to allow

for a maximum of hydrogen bonding to take place?

19. Why do cracks in pavement widen over time to become pot holes during the winter?

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COHESION AND ADHESION20. Explain the difference between adhesion and cohesion?

21. The object was gently placed on the surface of a body of water. Draw in the hydrogen bonds that allow this

object that is denser to stay afloat.

22. How does waters polar nature account for

its high surface tension?

23. Why does it hurt more to do a belly flop into a pool of water than dive in pencil style?

______________________________

24. How do cohesion and adhesion explain capillary action?

If you lay a penny on a flat surface and add several drops of water on the face of the penny, the water will form a dome that never spills off of the side of the penny. 25. Explain how adhesion and cohesion prevent the water from

spilling over the edge of the penny?

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SOLUTIONS AND SUSPENSIONS

26. Why is water called the universal solvent? What does polarity have to do with this?

27. How does water dissolve a substance like NaCl?

28. What do the terms hydrophilic and hydrophobic mean?

ACIDS, BASES, AND PHMatching: match the term with the following descriptions.

A. Polarity B. Acidic C. Basic

_______ 1. Unequal sharing of electrons

_______ 2. Lemon juice, pH 1.5

_______ 3. Lower concentration of H+ ions than pure water

_______ 4. Ammonia, pH 11.5

_______ 5. A slight negative charge at one end of a molecule, a slight positive charge on the other end

_______ 6. pH values that are below 7

_______ 7. Alkaline solutions

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2.4 Chemical Reactions and Enzymes Name

Biology Date Period:

Objectives: Explain how chemical reactions affect chemical bonds. Describe how energy changes affect how easily a chemical reaction will occur. Explain why enzymes are important to living things.

Background Information:Chemical Reactions - Everything that happens in an organism is based on chemical reactions. A chemical reaction is a process that changes one set of chemicals into another set of chemicals.

The elements or compounds that enter into the reaction are the reactants. The elements or compounds produced by the reaction are the products. Chemical reactions involve changes in the chemical bonds that join atoms in compounds.

Energy in Reactions - Some chemical reactions release energy; others absorb energy. Chemical reactions that release energy often occur on their own. Chemical reactions that absorb energy require a source of energy. The energy needed to get a reaction

started is called the activation energy.

Enzymes - An enzyme is a protein that acts as biological catalyst. A catalyst is a substance that speeds up the rate of a chemical reaction. Catalysts work by lowering a reaction’s activation energy.

In an enzyme-catalyzed reaction, the reactants are known as substrates. Substrates bind to a part of an enzyme called the active site and remain bound to the enzyme until the reaction is complete, when the products are released.

Temperature, pH, and regulatory molecules can affect the activity of enzymes.

Chemical Reactions1. What is a chemical reaction?

2. Complete the table about chemicals in a chemical reaction.

Chemicals in a Chemical Reaction

Term Definition

Reactants

Products

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20

Energy in Reactions3. The graphs below show the amount of energy present during two chemical reactions. One of the reactions

is an energy-absorbing reaction, the other is an energy-releasing reaction.

LABEL the type of reaction for each, label the energy level for the reactants and products, and then draw an arrow on each to show the energy of activation.

Type of reaction: Type of reaction:

4. What is released or absorbed whenever chemical bonds are formed or broken?

5. What is the energy of activation?

6. Of the two reactions shown, which one is more likely to start spontaneously and why?

Enzymes7. What is a catalyst?

8. Catalysts increase / decrease the rate of the reaction without being used up. (circle one)

9. What is a substrate? 21

10. How does the addition of a catalyst affect the energy of activation of a chemical reaction?

11. What type of catalysts affect biochemical reactions?

22

Use the diagram to answer the following questions. Label the enzyme, the active site, and the products in the diagram.

12. Write what is happening at each numbered part of the diagram.

(1)

(2)

(3)

For the following questions, refer to the Visual Analogy comparing the action of enzymes to a lock and key.13. How is a substrate and its enzyme like a lock and its key?

14. What is being unlocked in this analogy?

Some cells in your body can produce hydrogen peroxide (H2O2) to help fight infections. Hydrogen peroxide is one of many chemicals that can help cells at low levels and harm them at high levels. The level of hydrogen peroxide in a cell must be controlled. Hydrogen peroxide (H2O2) can break down into water (H2O) and oxygen gas (O2). An enzyme called CATALASE helps speed up this reaction.

15. Identify the reactants, the products and the enzyme in the reaction by writing R, P or E over the substances in the reaction.

2H2O2 + catalase 2H2O + O2 + catalase

Catalase is the enzyme, a biological (organic) catalyst. Hydrogen peroxide is the substrate for catalase.

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16. Identify three factors that affect/influence enzyme activity:

1.

2.

3.

17. What happens to an enzyme (protein) that has lost its active conformation?

18. Hydrogen peroxide can undergo the chemical reaction WITHOUT the use of catalase. All it needs is a little bit of energy to proceed to product. This process will just occur at a slower rate than with the catalase present. Explain why companies that make hydrogen peroxide need to store the solution in the dark bottle.

19. Complete the concept map. Some terms have been placed in the concept map for you.

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activation energy chemical reaction products substratecatalysts enzymes reactants

Chemicalreaction

Enzymes

Products

which work by lowering

needed to start a

can be sped up by

which begins with elements or compounds called

which combine to form

such as the biological ones called

which bind to a

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Chapter 2 Review Name: Biology Date: Period:

Please review the following sections for the test: Section 2.1 – Chemistry Section 2.2 – Water Section 2.4 – Reactions and Enzymes

Discuss the following questions with your partner and write responses on this paper or another sheet of paper.

1. Compare and contrast: a. protons, neutrons and electronsb. neutral atoms vs. ionsc. ionic vs. covalent bonds

2. Determine the number of atoms in the following compounds:a. NaOHb. H2SO4

c. 4 Co(ClO4)2

d. 5 Al2(SO2)3

3. What is the formula for water? a. Why is water polar? b. How do hydrogen bonds form? c. Draw 3 molecules of water with the partial charges and hydrogen bonds.

4. Compare and contrast:a. Adhesion and cohesionb. Capillary action and surface tension

5. Compare and contrast:a. Element vs. Compoundb. Solution vs. Suspensionc. What are the parts of a solution

6. Compare and contrast:a. Hydrophilic vs. Hydrophobicb. Why is water a Universal Solvent?

7. Compare and contrast:a. Acids and Bases – be specific in terms of H+ and OH- concentrations

Water – why is it neutral? b. How does pH change in an acid or a basec. What is buffer?

8. Compare and contrast:a. Reactants vs. Productsb. Endothermic vs. Exothermic reactions

9. Describe how enzymes work.26

Inorganic Vocabulary ReviewSections 2.1 and 2.2

Section 2.1: The Nature of Matter _______ 1. Anion

_______ 2. Atomic Mass

_______ 3. Atomic number

_______ 4. Cation

_______ 5. Covalent bond

_______ 6. Electron

_______ 7. Ion

_______ 8. Ionic bond

_______ 9. Isomer

_______ 10. Mass number

_______ 11. Neutron

_______ 12. Proton

_______ 13. Valence

a) refers to the number of protons

b) sum of protons and neutrons

c) positive subatomic particle

d) negative subatomic particle

e) subatomic particle with a neutral charge

f) electrons are transferred from one atom to another.

g) refers to outer energy electrons

h) when an atom gains or loses electrons

i) electrons are shared between atoms

j) the same molecular formula, different arrangement of atoms

k) weighted average of the isotopes of an element

l) gains electrons to form a negative charge

m) loses electrons to form a positive charge

Section 2.2: Properties of Water_______ 1. Acid

_______ 2. Adhesion

_______ 3. Base

_______ 4. Buffer

_______ 5. Cohesion

_______ 6. Hydrogen bonds

_______ 7. Hydrophilic

_______ 8. Hydrophobic

_______ 9. Polar Molecule

_______ 10. Solute

_______ 11. Solution

_______ 12. Solvent

_______ 13. Suspension

a) mixture in which all the components are evenly distributed

b) compound that produces hydroxide ions (OH-) in solution

c) mixture of water and non-dissolved material

d) substance that is dissolved in a solution

e) compound that forms hydrogen ions (H+) in solution

f) substance that does the dissolving in a solution

g) compounds that prevents sharp, sudden changes in pH

h) a molecule with an uneven distribution of electrons

i) attraction between molecules of the same substance

j) force of attraction between different kinds of molecules

k) weak attraction between a hydrogen atom and another atom with a

partial negative charge

l) substance that is attracted to water; dissolves well in water

m) substance that is repelled by water; doesn’t dissolve in water

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ACROSS2 A solution that produces more OH- ions then H+ ions.6 An intermolecular force (bond) that forms between the negative end of one water molecule and the

positive end of another water molecule.7 A solution that produces more H+ ions then OH- ions.8 Water takes a long time to heat up and cool down because it has high ___________________.9 A property of water where hydrogen bonds form between two molecules of the same substance.10

A substance that resists changes in pH.

13

A term that describes a nonpolar substance that cannot be mixed with water.

14

Water molecules form hydrogen bonds to a different substance besides water is an example of ________.

15

A name for the substance that is being dissolved in a solution.

16

The substance does the dissolving in a solution.

DOWN1 The state of water that has the most hydrogen bonds formed.3 A measure of how difficult it is to break the surface of a liquid because of hydrogen bonds.4 A subatomic particle that has a negative charge.5 A term that describes a polar substance that can be mixed with water.8 Maintaining internal stable internal body conditions.11

A type of chemical bond where electrons are shared.

12

Any molecule that has a positive end or a negative because of an uneven distribution of electrons.

PROPERTIES OF WATER

28

Use the clues and words to help you write the vocabulary terms from the chapter in the blanks. You may use a word once or not at all.

1. Smallest particle of a covalent compound

2. A protein that can catalyze a chemical reaction

3. Water molecules stick to another substance

4. An atom that has gained or lost an electron

5. The center of an atom

6. Found in the nucleus

7. Bond formed from the transfer of electrons

8. Substance that repels water

9. Electrons responsible for bonding

10. Look at the pH scale to the right. Which of the following substances is the strongest acid?A. tomato juice C. bleachB. milk D. lemon juice

11. Look at the pH scale to the right. Which of the following substances is the weakest base?A. ammonia C. bleachB. milk D. human blood

12. Look at the pH scale to the right. Which of the substances contains an equal

concentration of OH- and H+ ions?

13. Describe how an enzyme works (use the following terms: substrate, enzyme, active site, products).

14. What effect does a catalyst have on the activation energy?

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enzyme ion substrate molecule nucleusprotons neutrons electrons covalent ionicvalence hydrophilic cohesion adhesion hydrophobic

15. Describe the two main types of chemical bonds that are found in compounds.

________________________________________________________________________________________

________________________________________________________________________________________

16. If atoms lose one electron, they become charged particles or __________________ and will have a

____________________ charge. If they lose 3 electrons, the charge will be ___________.

17. If atoms gain electron(s), they will have a ____________________ charge. If they gain 3 electrons, the

charge will be _________.

18. Complete the table:

Compound Number of Each Atom Total Number of Atoms

Number of Molecules

C6H12O6

3 C6H12O6

CH3OH

Some cells in your body can produce hydrogen peroxide (H2O2) to help fight infections. Hydrogen peroxide is one of many chemicals that can help cells at low levels and harm them at high levels. The level of hydrogen peroxide (H2O2) in a cell must be controlled. Hydrogen peroxide can break down into water (H2O) and oxygen gas (O2). An enzyme called CATALASE helps speed up this reaction.

19. Identify the reactants, the products and the enzyme in the reaction by writing R, P or E over the substances in the reaction. Hydrogen peroxide is the substrate for catalase.

2H2O2 + catalase 2H2O + O2 + catalase

20. The diagram below shows how an enzyme like catalase works to break down a molecule like hydrogen peroxide into smaller molecules. In the diagram below, label the following:

Catalase, H2O2, H2O, and O2

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Venn Diagram - A Venn diagram is made up of overlapping circles. It is a useful tool for comparing two or even three topics. In each circle, write one of the topics that you want to compare. In the space where the circles overlap, write the features that the topics share. In the space where the circles do not overlap, write the features that are unique to each topic.

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