2. Today’s Objectives
I will define and classify two types of metabolism: photosynthesis and cellular respiration
I will compare and contrast photosynthesis and cellular respiration

3. Warm-Up
Define metabolism and name two important types of metabolism.

4. Metabolism – all of the chemical reactions in a cell
Chapter 8
Cellular Energy
Metabolism – all of the chemical reactions in a cell
Photosynthesis—light energy from the Sun is converted to chemical energy for use by the cell
Cellular respiration—organic molecules are broken down to release energy for use by the cell

5. Prior- Knowledge
Which law of thermodynamics describes how energy is conserved (not created or destroyed)?

6. Laws of Thermodynamics
Chapter 8
Cellular Energy
Laws of Thermodynamics
First law—energy cannot be created nor destroyed.
Derived from the law of conservation of energy.
Second law—energy cannot be converted without the loss of usable energy.
Example: When consumers convert chemical energy into kinetic energy, some energy is loss as heat to the environment but NOT destroyed.

7. Warm-Up
What is ATP and how is used to create energy?

8. ATP: The Unit of Cellular Energy
Chapter 8
Cellular Energy
ATP: The Unit of Cellular Energy
ATP (Adenosine Triphosphate)
has usable energy stored in the phosphate tail
releases energy when the bond between the second and third phosphate groups is broken

9. Chapter 8
Cellular Energy
Photosynthesis
Photosynthesis = process by which producers use the energy of the sun to make food
Stores energy in chemical bonds
sunlight (radiant energy) is converted to chemical energy
Occurs in the chloroplasts

10. Photosynthesis The Chemical Reaction
Chapter 8
Cellular Energy
Photosynthesis
The Chemical Reaction
Carbon dioxide and water are the reactants
Glucose and oxygen are the products
Carbon Dioxide + Water  Glucose + Oxygen

11. Photosynthesis Two Phases of Photosynthesis Light-Dependent Reactions
Chapter 8
Cellular Energy
Photosynthesis
Two Phases of Photosynthesis
Light-Dependent Reactions
Light-Independent Reactions or Dark Reactions

12. Photosynthesis Light Dependent Reactions
Chapter 8
Cellular Energy
Photosynthesis
Light Dependent Reactions
Chlorophyll is the green pigment in plants
What happens:
Cholorophyll absorbs light energy from the sun
Light energy energizes or excites electrons in chlorophyll
Enzymes transfer the energized (excited) electrons to ATP

13. Photosynthesis Light Independent Reactions
Chapter 8
Cellular Energy
Photosynthesis
Light Independent Reactions
These are also called the Dark Reactions
What happens:
ATP from the light-dependent reactions is used to convert water and carbon dioxide into glucose and oxygen

14. Chapter 8
Cellular Energy
Cellular Respiration
Cellular Respiration = process by which consumers obtain energy from the chemical bonds in food
Chemical bonds (found in organic molecules like sugar) are broken down to release energy (ATP)
Chemical energy is converted to kinetic energy and heat
Occurs in the mitochondria

15. Cellular Respiration The Chemical Reaction
Chapter 8
Cellular Energy
Cellular Respiration
The Chemical Reaction
The reverse of photosynthesis
Glucose and oxygen are the reactants
Carbon Dioxide and Water are the products
Glucose + Oxygen  Carbon Dioxide + Water + Energy

16. Comparing Photosynthesis and Cellular Respiration
Chapter 8
Cellular Energy
Comparing Photosynthesis and Cellular Respiration
Process
Reactants
Products
Energy Involved
Photosynthesis
carbon dioxide, water
glucose, oxygen
input of radiant energy (sunlight)
Cellular Respiration
release of chemical energy (ATP)

17. Review

18. In which metabolic process are molecules
Chapter 8
Cellular Energy
Wrap-Up (Oct. 24)
In which metabolic process are molecules
broken down to produce carbon dioxide and
water?
photosynthesis
cellular respiration
homeostasis
fermentation

19. Where in the plant cell does photosynthesis take place?
Chapter 8
Cellular Energy
Wrap-Up (Oct. 24)
Where in the plant cell does photosynthesis
take place?
chloroplasts
Golgi apparatus
mitochondria
vacuoles

20. What is the overall purpose of cellular respiration?
Chapter 8
Cellular Energy
Wrap-Up (Oct. 24)
What is the overall purpose of cellular
respiration?
to make ATP
to process H2O
to store glucose
to deliver oxygen

21. Photosynthesis converts light energy to
Chapter 8
Cellular Energy
Wrap-Up (Oct. 24)
Photosynthesis converts light energy to
stored chemical energy. What form of
chemical energy is used in cellular respiration?
glucose
oxygen
chlorophyll
carbon