Chapter 4: Energy

1. Chapter 4: Energy Clicker Questions by Kristen Curran, University of Wisconsin, Whitewater

2. Which answer is an example of potential energy? Heat from a fire Sledding down a hill A candy bar Walking to your car

3. In which process would you expect that the conversion of a form of potential energy into heat might be useful? The mitochondria produce heat during cellular respiration which maintains body temperature. In the winter, some of the heat produced by combustion can be used to maintain the temperature in the passenger compartment of your car. The increased cellular respiration when exercising creates heat and you begin to sweat. 1 and 2 All of the above

4. Which letter in the diagram below is an example of potential energy? A B C D A and C B and D A D B C

5. When a plant in a pot gains weight, which input into the photosynthesis pathway added to the weight of the plant? Carbon harvested from carbon dioxide Oxygen harvested from carbon dioxide Hydrogen harvested from water Oxygen harvested from water

6. Which wavelength of light would you expect is NOT absorbed by chlorophyll a or b? Red Yellow Blue Green Purple

7. Classroom Catalyst What do chlorophyll and fireworks have in common?

8. What do chlorophyll and fireworks have in common? • You have seen that chlorophyll is made up of pigments that absorb light energy at specific wavelengths. How is the absorption of energy by the electron in the pigment and the firework the same? Are they different? • If harnessed in a different way, could the energy possessed by the excited electrons in the fireworks be used by plants to make food? • What are the energy sources for each?

9. Follow up question: In the cell, excited chlorophyll a molecules: return to the normal state after releasing the energy in the form of light. return to the normal state after passing on electrons to another molecule. return to the normal state after releasing the energy to directly form ATP. remain in the normal state after passing on the energy to chlorophyll b

10. Review: Which answer is an example of a molecule with high potential energy? NADPH NADP+ H2O O2 Both 1 and 2

11. Why does NADPH have a high potential energy? Because it is used for electron transport Because it is equivalent to ATP Because it stores energy that is used to make G3P Because it contains phosphate that can be put on ADP to form ATP

12. What is the cost associated with a plant using C4 or CAM photosynthesis? More energy is used to form sugars. More CO2 is required to form sugars. The harvest of light energy and carbon fixation are temporally separated. Less water is lost in hot, dry climates.

13. Review: The energy used by plants and animals ultimately comes from… food soil sun air

14. If glycolysis is very inefficient, why do it? Because pyruvate can be metabolized to yield more water Because pyruvate can be metabolized to yield more CO2 Because pyruvate can be metabolized to absorb more electrons Because pyruvate can be further metabolized to yield more energy

15. Energy is obtained from a molecule of glucose in a stepwise fashion. Why would this method of harvesting energy be beneficial to the cell/organism? It is more efficient to form sugars a little bit at a time rather than all at once. It is more efficient to release energy a little bit at a time rather than in one giant explosion. It is more efficient to make ATP from ADP than to make it from scratch. All of the above.

16. Plants have both chloroplasts and mitochondria. Why? The mitochondria also synthesize sugars. The mitochondria are used to convert oxygen to carbon dioxide for the plant. The mitochondria break down sugars produced by photosynthesis to provide energy for the cellular work of the plant. The mitochondria break down fat produced by photosynthesis to provide energy for the cellular work of the plant.

17. Which process below uses anaerobic respiration? Running 10 miles Swimming 1 mile Sprinting 100 meters Making beer 3 and 4