Course: Biology Agricultural Science & Technology. Unit: Chemistry of Life

Transcription

1 Course: Biology Agricultural Science & Technology Unit: Chemistry of Life State Standard II: Students will understand that all organisms are composed of one or more cells that are made of molecules, come from preexisting cells, and perform life functions. State Objective 1: Describe the fundamental chemistry of living cells. a. List the major chemical elements in cells (i.e., carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur, trace elements). b. Identify the function of the four major macromolecules (i.e., carbohydrates, proteins, lipids, nucleic acids). c. Explain how the properties of water (e.g., cohesion, adhesion, heat capacity, solvent properties) contribute to maintenance of cells and living organisms. d. Explain the role of enzymes in cell chemistry. Unit Objectives: A. Students will be able to identify and define the parts of an atom. B. Students will list the major chemical elements and compounds. C. Students will explain the properties of water. D. Students will summarize the importance of water in agriculture. E. Students will identify the function of the four major macromolecules. F. Students will explain the roll of enzymes. Materials Needed (Equipment): Projector for PPT presentation Tofu Soy Sauce Butter Soap Corn Starch 6 Test tubes with stoppers per group Water Toothpicks Gumdrops Note cards with common elements and symbols written on them (ie. C = Carbon) Water (for cohesion and adhesion activity) Celery stalk (1 per student) Cups for water ( 1 per student) Food Coloring Properties of water lab sheet copies and supplies Chemistry of Life Review Worksheet Copies 10,000 Pyramid Fact Cards Facilities:

2 Classroom Interest Approach: (20 minutes) Break students into small groups according. Each group needs six test tubes. Have each group label their six test tubes as follows: tofu, soy sauce, butter, soap, starch, and sugar. Next have students place a tiny amount of each sample in the appropriate test tube. Then half-fill each test tube with water. Stopper the test tubes. Shake each test tube for two minutes. Then have students record their observations of each sample. Ask the following questions: 1. Which substances dissolved easily in water? (Students should observe that soy sauce, soap and sugar dissolved easily.) 2. Tofu, starch and butter consist mostly of large molecules. (Protein starch and fat respectively). Soy sauce, sugar and soap contain smaller molecules that are related to large molecules. Are the large molecules more or less soluble than the smaller molecules? (Students should conclude that the large molecules are less soluble than the smaller molecules.) Objective A: Students will be able to identify and define the parts of an atom. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Q: What is an atom? A1. The study of chemistry begins with the basic unit of matter, the atom. The Greek word atomos, which means unable to cut. This word was first used nearly 2500 years ago by Greek philosopher Democritus. Democritus asked a simple question If you take an object like chalk and break it in half are both pieces still chalk? Yes, suppose you break the chalk down again and again and again. Can you continue to divide without limit? Or is there a limit? Demociritus thought that their had to be a limit and he called the smallest fragment the atom, a name scientists use today. A1. PPT Slide 2 - Background Discussion A2. PPT Slide 3

3 A2. Atoms the SMALLEST particle that can exist and still be considered a certain kind of matter All LIVING and NONLIVING things are made of atoms Note: Underlined terms are for students to record in their notes for future reference and study. Q: What are the parts of an atom? A3. ELECTRONS -- negatively charged PROTONS -- positively charged; found in nucleus NEUTRONS -- neutral; found in nucleus A4. A3. PPT Slide 4 A4. PPT Slide 5 Have students copy the picture of the atom. Electrons Protons& Neutrons (Nucleus) Energy Levels A5. Lecture on protons, neutron and electrons. Protons are positively charged particles and neutrons carry no charge. Strong forces bind protons and neutrons together to form the nucleus at the center of the atom. Electrons are negatively charge particles. Electrons are in constant motion in the space surrounding the nucleus. They are attracted to the positively charged nucleus but remain outside the nucleus because of the energy of their motion. Because atoms have equal numbers of protons and electrons, atoms are neutral. A6. Review using Michelangelo E- Moment below. Activity:

4 E-moment: Michelangelo (Using Models): Display a model of an atom. Then have students build their own 3-D model of an atom using toothpicks and gumdrops. Have students make small labels to mark electrons, neutrons and protons. Directions: 1. When you hear the word JUMP you will proceed to the front of the classroom in an orderly manner to get enough gumdrops and toothpicks to create a model of an atom. 2. Think carefully about what you will need. What questions are there? 3. JUMP you will proceed to the front Objective B: Students will list the major chemical elements and compounds. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Q: What is an element? B1. Elements -- a substance that is made of only ONE kind of ATOM B2. Major Elements of Life C = Carbon H = Hydrogen O = Oxygen P = Phosphorus K = Potassium I = Iodine N = Nitrogen S = Sulfur Ca = Calcium Fe = Iron Mg = Magnesium Na = Sodium Cl = Chlorine B3. Where do we find these elements? B1. PPT Slide 6 (More than 100 elements are known, but only about two dozen are commonly found in living organisms. ) B2. PPT Slides 7-9 Teach using pneumonic device: CHOPKINS CaFe MgNaCl B3. PPT Slides 11 and 12 Use slides to have a discussion on where elements are found. Relate back to students using elements in a human body.

5 B4. Review Elements using the Go and Get It Moment below (PPT Slide 13) Activity: Go and Get It: Write the common elements and their symbols on note cards. Before students arrive tape the cards under desks, chairs, or tables or on the overhead projector, board door, or wall, or slip them between books on the shelf. Review at end. 1. Hidden around the room are the basic elements of life. 2. When I say GO get into four groups. 3. GO 4. When I say Atom each group is to collect one set of element cards. CHOPKINS CaFe MgNaCl 5. When all 13 cards are collected have everyone in your group sit down. 6. Great work, now select a secretary to write the name of each element on the card. Q: What is a compound? B5. Compounds matter that is made of more than ONE kind of ATOM Compounds are made by atoms sharing or taking ELECTRONS from the other atoms in the compound B6. Compound Example Water ( H 2 O ) each molecule is made of two HYDROGEN atoms and one OXYGEN atom B5. PPT Slide 14 Discussion on adding elements together to make compounds. Recall prior knowledge from the lesson about atoms and the components of an atom. Refer back to gumdrop models. B6. PPT Slides 15 and 16 Using these slides discuss the makeup of a water molecule and why it is a compound.

6 Q: What are the two types of chemical bonds? B7. Chemical Bonds The main types of Chemical Bonds in a compound are: Ionic Bonds Covalent Bonds B8. Ionic Bonds An IONIC BOND is formed when one or more electrons are transferred from one atom to another. B7. PPT Slides 17 Have students continue to add key points to their notes using the slides. B8. PPT Slides 18 and 19 B9. Covalent Bonds A COVALENT BOND is formed when electrons are shared between atoms. When the atoms share two electrons, the bond is called a single bond. When atoms share four electrons it is a double bond. When atoms share six or more electrons it is a triple bond. The structure the results when atoms are joined together by covalent bonds is called a MOLECULE. B9. PPT Slides 20 & 21 B10. Review Bonds and Compounds

7 Objective C: Students will explain the properties of water. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Q: What are the properties of water? C1. The Water Molecule One atom of oxygen binds to two atoms of hydrogen to form H20. Like all molecules a water molecule (H 2 0) is neutral. Water molecules are held together by a hydrogen bond. Hydrogen Bonds are not as strong as covalent or ionic bonds. The hydrogen atoms are attached to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. Since opposites attract, water molecules tend to attract each other, making water kind of "sticky." C1. PPT Slide 22 & 23 Teach the basic concepts of the structure of a water molecule using slides 22 and 23. Have students write underlined and bolded words in their notes. C2. C2. PPT Slide 23 Have students draw the water molecule in their notes. C3. Properties of Water Cohesion is an attraction between molecules of the same substance. C3. PPT Slides 24 Lecture on Cohesion as a property of water.

8 Water s cohesion causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surface. C4. C4. PPT Slide 25 Discussion on Cohesion Cohesion explains why insects and spiders, such as this tarantula can rest on the water s surface. How does the tarantula s physical structure help it to stay afloat? C5. Properties of Water Adhesion is an attraction of between molecules of different substances. Adhesion between water and glass causes water to rise against the force of gravity. This is known as capillary action. Capillary action is one of the forces that draws water out of the roots of a plant and up into it stems and leaves. Cohesion holds the column of water together as it rises. C5. PPT Slide 26 C6. Review Properties of water using the lab activities below related. Activity: Properties of water lab (See attached lab sheet) Activity: Each student needs: 1 glass of colored water

9 1 celery stalk Process: Place celery stalk in colored water overnight. Observe the celery leaves. Review the process of cohesion, adhesion and capillary action Objective D: Students will summarize the importance of water in agriculture. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Q: Why is water important to Agriculture? D1. Why is water so important to agriculture? At least 75% of animal body mass is water Plants contain 70-80% water Transports nutrients and wastes Dissolves compounds -- Universal Solvent Regulates body temperature in animals Provides structure for plants D2. Review using Hieroglyphic moment D1. PPT Slides Discussion on the importance of water in agriculture. Activity: Hieroglyphic Moment: After reviewing the importance of water, have students take a sheet of paper and draw three pictures of the importance of water in agriculture. Encourage students to come up with additional ideas not found in their notes. Objective E: Students will identify the function of the four major macromolecules Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Q: What is a macromolecule? E1. Lecture/Discussion: Many molecules in living cells are so large that they are known as macromolecules

10 meaning giant molecules Macromolecules are made from thousands or even hundreds of thousands of smaller molecules. Macromolecules are formed by a process known as polymerization, in which large compounds are built by joining smaller ones together. It would be difficult to study the millions of organic compounds if they were not classified into groups. Organic compounds contain the element carbon. Carbon has the ability to form millions of different large and complex structures. Q: What is the structure and function of carbohydrates? E2. Carbohydrates Provide energy Three Types o Monosaccharides o Disaccharides o Polysaccharides E3. Monosaccharide simple SUGAR contain C 6 H 12 O 6 GLUCOSE, FRUCTOSE, AND GALACTOSE E4. Disaccharides double SUGAR contain two RINGS SUCROSE and LACTOSE E5. Polysaccharides complex CARBOHYDRATES made of RINGS of SUGAR STARCH, CELLULOSE, and GLYCOGEN E6. Structure of Carbohydrates E2. PPT Slide 32 E3. PPT Slide 33 Discussion on Monosaccharide E4. PPT Slide 34 Discussion on Disaccharides E5. PPT Slide 35 - Discussion on Polysaccharides E6. PPT Slide 36 Discuss the structure of carbohydrates, be sure to review elements and bonds from previous lessons.

11 Q: What is the structure and function of proteins? E7. PPT Slide 37 E7. Proteins STRUCTURE and FUNCTION Made of H, O, C, N E8. Structure of Proteins Amino Acids building BLOCKS 20 different kinds all have the same elements but in different amounts Polypeptides chains of AMINO ACIDS Joined by peptide bonds Proteins chains of POLYPEPTIDES Used to make SKIN, HAIR, MUSCLE, ORGANS, etc. E8. PPT Slide 38 E9. PPT Slide 39 Review the Structure and Function of Proteins E9. Beef Carbon Atoms Chemical Bonds Protein Q: What is the structure and function of lipids? E10. Lipids FATTY molecules used to store ENERGY Made of long chains of H & C E10. PPT Slide 40 Lecture/Discussion

12 followed by COOH Do not DISSOLVE in WATER Lipids have less OXYGEN than carbohydrates Examples of Lipids are: FATS, OILS, AND WAXES E11. Lipid Molecule E11. PPT Slide 41 Review Lipid Molecule structure and function. Q: What is the structure and function of nucleic acids? E12. Nucleic Acids Store INFORMATION that controls CELL activities Made of a PHOSPHATE a SUGAR, and a BASE. Examples of Nucleic Acids are: DNA and RNA E13. E12. PPT Slide 42 E13. PPT Slide 43. Review Nucleic Acid Structure and Function E14. Write following questions on board for a review. 1. Name four groups of organic compounds found in living things. 2. Describe at least one function of

13 each group of organic compounds 3. List the three types of carbohydrates. 4. What makes lipids so hard to break down? Objective F: Students will explain the roll of enzymes. Curriculum (Content) (What to teach) Instruction (Methodology) (How to teach) Q: What are enzymes? F1. Background Lecture and Discussion of the following key points: Energy is released or absorbed whenever chemical bonds are broken. Chemical reactions involve breaking and forming bonds, they involve changes in energy. Enzymes are proteins that act as a biological catalysts. Catalysts is a substance that speeds up the rate of a chemical reaction. F2. Cells use enzymes to speed up chemical reactions that take place in cells. Enzymes must collide with enough energy to break bonds creating a chemical reactions. Chemical reactions create energy. F2. PPT Slide 44 F3. Unit Review Have students complete Chemistry of Life Review Worksheet F4. Unit Review Activity 10,000 Pyramid Review

14 Activity: 10,000 Pyramid E-moment (Sample set of fact cards attached, print out, cut and fold in half so clues are on one side and terms on back side) 1. Teach the Content 2. Select key information: Extract the most important information. Place each piece of information on its own 4 x 6 card. The number of cards needed is dependent upon the information selected from the unit. You will need one set of fact cards for every three to five people. 3. Explain Roles: In each group there are three rolls: player, clue giver, and teleprompter. The clue giver and player sit facing each other, with the teleprompter standing behind the player, displaying the fact cards one at a time to the clue giver. The clue giver reads the facts to the player, adding additional information as necessary to help the player guess the fact. 4. Play the Game: The game is played in rounds of sixty seconds each. When the player correctly guesses the information on a card the teleprompter places the card on the table. If the player is having a difficult time guessing a card, either the clue giver or the player may ask to pass to the next card. After each round the groups count the player s correct answers and each group score is recorded on the board. With each new round everyone switches roles and the entire deck is shuffled for the new player. If there is more than three people per group have them decide how to rotate. Play as many rounds as needed to allow each learner to play each role at least once. Should a group get through the entire deck, the cards are shuffled and play continues. Evaluation: Jeopardy Test Review Chemistry of Life Test and Key References: Prentice Hall Biology by Kenneth R, Miller and Joseph S. Levine. 2002, Pearson Education, Upper Saddle River, New Jersey. Strategies for Great Teaching by Mark Reardon and Seth Derner, 2004, Zeyphry Press, Chicago, Illinois

15 ~Comes from Greek word atomos, meaning unable to cut. ~Smallest particle that can exist and still be considered a certain kind of matter ~All living and non living things are made up of this. ATOM C Carbon H Hydrogen

16 O Oxygen P Phosphorous K Potassium I Iodine

17 N Nitrogen S Sulfer Ca Calcium

18 Fe Iron Mg Magnesium Na Sodium Cl Chlorine Made of more than one kind of atom.

19 Made by sharing or taking electrons from other atoms in compound. Used to speed up chemical reactions in a cell Compound 2 Hydrogen Atoms, 1 Oxygen Atom H20 Molecule Enzymes Water Cohesion Adhesion Capillary Action Properties of Water

20 Attraction of some molecules to one another. Why water creates beads or droplets Cohesion Attraction of molecules between different substance Adhesion 75% Animal Body Mass Plants contain 80% Transports nutrients and wastes Regulates body temperature Provides structure for plants Reasons why water is important to Agriculture Giant Molecules Formed by thousands of small molecules 4 major organic kinds Macromolecules

21 Provide energy 3 kinds Mono, Di., and Poly Common Examples: Sugar, starch, glucose, fructose, galacatose Provide structure and function Made by building blocks known as amino acids Make skin, hair, muscle, organs Made of H, O, C, N Creates a molecule by joining atoms Forms a bond by sharing electrons Two main kinds found in compounds Ionic Covalent Carbohydrates Proteins Covalent Bond

22 BONDS Forms a bond when electrons are transferred from one atom to another Ionic Bond Fatty Molecules Store Energy Waxes Oils Fats Contain H & C chains followed by COOH Store Information Made of Sugar, Phosphate & a Nitrogen Base Examples are DNA & RNA Lipids Nucleic Acids