1. Converting Light Energy to Chemical Energy
Photosynthesis
Converting Light Energy to Chemical Energy

2. Photosynthesis
Where did this redwood tree and saguaro cactus come from?
Where did the molecules that make up the cells that make up the plants come from?

3. Photosynthesis Plants use water + carbon dioxide to make sugar
Plants use sugars as material for building cells and energy to run cells
Humans use sugars for:
Food
Shelter
Energy
Clothing
Medicines

4. Photosynthesis Overview
Occurs in the leaves of green plants
Occurs in specific cells in the middle layer of the leaf
Occurs in organelles – called chloroplasts – within the cells of that layer
Reactants and Products
(6) CO2 + (6) H2O + light energy (1) C6H12O6 + (6) O2

5. Photosynthesis Overview

6. Photosynthesis Overview
Light-dependent reactions convert light energy to chemical energy
Light-independent reactions convert CO2 to sugar

7. Light dependent reactions
Use the following resources: textbook; reading analysis; this power point; internet (esp. videos)
Construct a concept map of the light dependent reactions
A concept map makes connections between important terms and identifies those connections with verbs
Use the following terms:
Chlorophyll; light energy; water; H+ ions; electrons; oxygen; ADP; ATP; NADP+; NADPH; thylakoid space; thylakoid membrane; electron transport chain

8. Light Dependent Reactions
Also called light reactions or photochemical reactions

9. Light dependent reactions
Water + Light  ATP + NADPH + Oxygen
Light energy is attracted by chlorophyll pigments
Energy splits H2O into (2) H+ + O + (2) e–
O2 is released as waste

10. Light dependent reactions
Water + Light  ATP + NADPH + Oxygen
H+ collects in the thylakoid membrane
Movement of H+ helps to make ATP
H+ combines with NADP to make NADPH
NADPH and ATP are used in dark reactions

11. Light dependent reactions
Water + Light  ATP + NADPH + Oxygen
e– (electrons) are used by electron transport chain
Movement along chain moves more H+ into thylakoid
Used to combine NADP and H+ into NADPH
NADPH and ATP are used in dark reactions

12. light dependent reactions
Light Dependent Reactions Video

13. Light independent reactions
Use the following resources: textbook; reading analysis; this power point; internet (esp. videos)
Construct a concept map of the light dependent reactions
A concept map makes connections between important terms and identifies those connections with verbs
Use the following terms:
Carbon dioxide (1-carbon molecule); NADPH; NADP+; ADP; ATP; stroma; carbon fixation; reduction; regeneration; C5 sugar; C3 sugar; C3 sugar

14. Light independent Reactions
(3) C6 Sugar
(6) C3 Sugar
(5) C3 Sugar
(3) C5 Sugar
(3) CO2
ATP
NADPH
ATP
(1) C3 Sugar

15. light independent reactions
Also called dark reactions, Calvin cycle or photochemical reactions
Three phase cycle that starts and finishes with a 5-carbon molecule

16. light independent reactions
ATP + NADPH + Carbon Dioxide  Glucose
Stage 1 – Carbon Fixation
1-carbon (CO2) added to a 5-carbon with help of enzyme rubisco
6-carbon molecule breaks into (2) 3-carbons

17. light independent reactions
ATP + NADPH + Carbon Dioxide  Glucose
Stage 2 – Reduction
H+ added from NADPH
P added from ATP
This ‘energizes’ the 3 carbon

18. light independent reactions
ATP + NADPH + Carbon Dioxide  Glucose
Stage 3 – Regeneration
3 carbon sugar is removed
5-carbon molecule is restored (using ATP)
Cycle must complete (2) rotations to make (1) glucose molecule

19. Light independent reactions
Light Independent Reactions Video

20. Comparing Light Dependent and Light Independent Reactions
Construct a Venn diagram comparing the two parts of photosynthesis
Use the following terms:
Light energy; chemical energy; ATPADP; ADPATP; ATP; NADPH; NADPNADPH; NADPH NADP; H+; e-; CO2; H2O; thylakoid; stroma; chlorophyll; C6H12O6; electron transport chain; Calvin cycle

21. Cellular Respiration
Converting Chemical Energy from Carbohydrates into Chemical Energy of ATP

22. Cellular Respiration (Aerobic )
How do cells transform matter and energy?
What are the major inputs and outputs of cell respiration?
What is the relationship between cell respiration and study photosynthesis?

23. Cell Respiration and Photosynthesis
These are ‘opposite’ processes
Products of photosynthesis are reactants of cell respiration and vice versa.
Energy stored in photosynthesis is released through cellular respiration

24. Cell Respiration and Photosynthesis
• Photosynthesis stores small packets of energy into a larger packet.
Like turning in one hundred $1 bills to get a $100 bill
Cell Respiration takes a big packet of energy and breaks it into smaller packets.
Like turning in a $100 bill and getting five $20 bills.

25. Cell Respiration Overview
In mitochondria of eukaryotic cells, oxygen helps the break- down of sugars (glucose) to release energy to be used by the cell (ATP)
Products and Reactants
(1) C6H12O6 + (6) O (6) CO2 + (6) H2O + ATP

26. Cell Respiration – Reactants and Products
Glycolysis
ATP C3
ATP
NAD+ O2
H2O
Krebs Cycle
Electron Transport Chain
NADH
ATP
CO2
C6H12O6 + (6) O (6) CO2 + (6) H2O + ATP

27. Glycolysis
Glucose (6 carbon) breaks down into pyruvate (3 carbon) and ATP (energy)
Similar to reversing the final stage of photosynthesis when two 3-carbon sugars were used to make glucose

28. Krebs Cycle
Pyruvate (3 carbon) breaks down into CO2 (1 carbon) and electrons are used to generate ATP (energy)
Similar - in reverse - to the Calvin cycle in photosynthesis

29. Electron Transport Chain
Electrons and H+ from glycolysis and Krebs cycle are used to generate ATP
At the end they come together with oxygen to form water
Similar, but in reverse, to the ETC in the light reactions of photosynthesis

30. Cell Respiration– Energy Yield
(1) glucose molecule yields ATP molecules