1. Photosynthesis and Respiration
Unit 3

2. Think back to Energy Transfer…
Living things use energy for
Growth
Repair
Reproduction
Metabolism
The collection of reactions that occur in a cell

3. Metabolism Involves either:
Using energy to build molecules (condensation reactions) or
Breaking down molecules to release the stored energy (hydrolysis)

4. Building Molecules That Store Energy
Photosynthesis is the process by which light energy is converted to chemical energy
Organisms that use energy from sunlight (or from chemical bonds in inorganic substances) to make organic compounds are called autotrophs

5. Breaking Down Food for Energy
Organisms that must get energy from food instead of directly from sunlight (or inorganic substances) are called heterotrophs
Heterotrophs get energy from food through the chemical process of cellular respiration, remember that autotrophs perform cellular respiration also!

6. PHOTOSYNTHESIS

7. Photosynthesis
Photosynthesis changes the energy of sunlight into the chemical energy stored in glucose bonds
Photosynthesis is the connection between the sun and the energy needs of living systems

8. Equation
6CO2 + 6H2O  C6H12O6 + 6O2
carbon dioxide + water  glucose oxygen

9. The chlorophyll inside the chloroplast of leaves absorb light
Absorption of light
In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll
The chlorophyll inside the chloroplast of leaves absorb light
Chlorophyll does not absorb all the wavelengths of visible light equally

10. Inside the Chloroplast
Chloroplast – organelle in plants where photosynthesis takes place
Thylakoids – Saclike photosynthetic membranes
Grana- Stacks of thylakoids
Stroma- aqueous region outside the grana

12. Step 1 - Light-Dependent Reactions
Breaks apart H2O to produce oxygen gas
Convert ADP and NADH+ into ATP and NADPH
Takes place within the thylakoid membranes in the chloroplast

13. Step 2 - Calvin Cycle ( aka light-INdependent reactions)
Uses ATP and NADPH from the light dependent reactions
Produces high-energy sugars
Takes place in the stroma of the chloroplasts
Does not require light

14. Factors Affecting Photosynthesis
Water
Temperature
Depends on enzymes that function best between 0oC and 35oC
Intensity of light
Increasing light intensity increases the rate of photosynthesis to a point
Carbon Dioxide Concentration
Nutrients

15. CELLULAR RESPIRATION

16. Cellular Respiration 3 Stages of Aerobic Cellular Respiration:
Glycolysis does not require oxygen.
Aerobic respiration: oxygen is present, glycolysis is followed by the Krebs cycle and then the electron transport chain.
Anaerobic respiration: no oxygen, glycolysis is followed by fermentation
3 Stages of Aerobic Cellular Respiration:
Glycolysis
the Krebs cycle
the electron transport chain
Each of the 3 stages of cellular respiration uses energy from food to produce ATP

17. 1.Glycolysis Respiration begins with a pathway called Glycolysis.
Glycolysis releases a small amount of energy.
Uses 2 ATP to make 4 ATP and 2 pyruvic acids

18. Next step  to the Mitochondria
The “power house” of the cell, because most of the ATP is produced here.

19. 2. The Krebs Cycle Oxygen is required
During the Krebs cycle, pyruvic acid is broken down into:
CO2
NADH
FADH2
ATP: The Krebs Cycle makes 2 ATP

20. 3. Electron Transport
Each pair of high-energy electrons moves down the electron transport chain (ETC) and provides the energy to produce more ATP.
The break down of glucose by aerobic cellular respiration results in the production of 36 molecules of ATP.

21. What happens when there is NO OXYGEN?
When oxygen is not present, glycolysis is followed by a different pathway.
2 types of fermentation: anaerobic (no oxygen)
Lactic Acid Fermentation
Alcoholic Fermentation

22. What happens during fermentation?
No ATP are produced
Lactic Acid Fermentation
Pyruvic acid  lactic acid (lactate)
Alcoholic Fermentation
Pyruvic acid  ethanol & CO2
DURING ANAEROBIC RESPIRATION ONLY 2 ATP ARE MADE

23. Why ATP Adenine Triphosphate?
A high energy molecule that stores energy needed by cells
Made in the mitochondria
Composed of:
Ribose (5 carbon Sugar)
Adenine (nitrogenous base)
3 phosphate groups (group of molecules made up of phosphorous and oxygen)

24. Releasing Energy from ATP
The removal of 1 phosphate group from ATP produces ADP (Adenosine DiPhosphate)
This reaction releases energy in a way that enables cells to use the energy

25. PLANTS ALSO PERFORM RESPIRATION
Plants also contain the organelle, mitochondria, which converts the high energy carbohydrates made by the plant through photosynthesis in the chloroplast into ATP for the plant to use to perform cellular functions.