Animals Unit Activity 4.1 Molecular Models for Cows Moving and Functioning: Cellular Respiration

1. Carbon: Transformations in Matter and Energy Environmental Literacy ProjectMichigan State University Animals UnitActivity 4.1 Molecular Models for Cows Moving and Functioning: Cellular Respiration

2. Unit Map You are here

3. Connecting Questions about Processes at Different Scales

4. How do a cow’s muscle cells get energy to contract the muscles and move? Food Digestion Energy:Cellular respiration

5. Connecting the Atomic-Molecular Scale to the Macroscopic Scale Chemical change

6. Three Ways to Represent Molecules:Glucose (a Kind of Sugar)

7. How atoms bond together in molecules • Atoms in stable molecules always have a certain number of bonds to other atoms: • Carbon: 4 bonds • Oxygen: 2 bonds • Hydrogen: 1 bond • Oxygen atoms do NOT bond to other oxygen atoms if they can bond to carbon or hydrogen instead. • Chemical energy is stored in bonds between atoms • Some bonds (C-C and C-H) have high chemical energy • Other bonds (C-O and O-H) have low chemical energy

8. Making the reactant molecules: glucose and oxygen Complete Steps 1 and 2 in Part B of your worksheet. Remember that this process is happening in all of the cells in the cow. Today, let’s think about a muscle cell.

9. Photo of reactant molecules: C6H12O6 (sugar) and O2 (oxygen)Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Glucose Chemical change Oxygen Products Reactants Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away).

10. Important: When you are finished constructing the reactants, put all extra pieces away.

11. Rearranging the Atoms to Make Product Molecules: Carbon Dioxide and Water Complete Steps 3 and 4 in Part B of your worksheet. Remember that this process is happening in all of the cells in the cow. Today, let’s think about a muscle cell.

12. Photo of product molecules: CO2 (carbon dioxide) and H2O (water)Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Chemical change Carbon dioxide Water Products Reactants Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away).

13. Comparing photos of reactant and product molecules Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products. Glucose Chemical change Carbon dioxide Water Oxygen Products Reactants Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away).

14. What happens to atoms and energy in cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Oxygen Motion and heat energy

15. What happens to carbon atoms and chemical energyin cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Carbon atoms become part of carbon dioxide molecules and Chemical energy is transformed into energy for cell work and heat energy. Oxygen Motion and heat energy

16. What happens to atoms and energy during cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Oxygen Motion and heat energy

17. What happens to carbon atoms during cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Carbon atoms become part of carbon dioxide molecules. Oxygen Motion and heat energy

18. What happens to oxygen and hydrogen atoms during cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Oxygen and hydrogen atoms become part of carbon dioxide and water molecules. Oxygen Motion and heat energy

19. What happens to chemical energy during cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Chemical energy is transformed into energy for cell work and heat energy. Oxygen Motion and heat energy

20. What happens to atoms and energy during cellular respiration? Carbon Dioxide Glucose Reactants Chemical change Water Products Atoms last forever! Energy lasts forever! Oxygen Motion and heat energy

21. Atoms last forever! Compare the atoms in the reactants and the products.

22. Energy lasts forever! Compare the energy before and after the reaction

23. Discuss with the class • Did the number and type of atoms stay the same at the beginning and end of the chemical change? ____ • Did the number of twist ties (representing energy) stay the same at the beginning and end of the chemical change? ____ • Why do the numbers of atoms and twist ties have to stay the same?

24. Writing a Chemical Equation • Chemists use chemical equations to show how atoms of reactant molecules are rearranged to make product molecules • Writing the equation in symbols: Chemists use an arrow to show how reactants change into products:[reactant molecule formulas] product molecule formulas] • Saying it in words: Chemists read the arrow as “yield” or “yields:”[reactant molecule names] yield [product molecule names] • Equations must be balanced: Atoms last forever, so reactant and product molecules must have the same number of each kind of atom • Try it: can you write a balanced chemical equation to show the chemical change when animals move (use energy)?

25. Chemical equation for cellular respiration • C6H12O6 + 6O2 6 CO2 + 6 H2O • (in words: glucose reacts with oxygen to yield carbon dioxide and water)

26. Exit Ticket • Conclusions • What happens to glucose and oxygen during cellular respiration? • Predictions • Where do you think cellular respiration occurs?