1. Journal
Explain the relationship between photosynthesis and cellular respiration. Define autotroph and heterotroph.

2. What you need to know:
The summary equation of photosynthesis including the source and fate of the reactants and products.
How leaf and chloroplast anatomy relates to photosynthesis.
How photosystems convert solar energy to chemical energy.
How linear electron flow in the light reactions results in the formation of ATP, NADPH, and O2.
How chemiosmosis generates ATP in the light reactions.
How the Calvin Cycle uses the energy molecules of the light reactions to produce G3P.
The metabolic adaptations of C4 and CAM plants to arid, dry regions.

3. Chapter 7 Photosynthesis Name a plant you have seen recently. CO 7

4. What is a plant anyway? 7.1 Photosynthetic Organisms
A. Photosynthesis transforms solar energy
B. Organic molecules built by photosynthesis provide both the building blocks and energy for cells.
Figure 7.1a

5. C. Plants use the raw materials: carbon dioxide and water
Figure 7.1b
C. Plants use the raw materials: carbon dioxide and water
D. Chloroplasts carry out photosynthesis
Figure 7.1b

6. Figure 7.1c
E. Chlorophylls and other pigments involved in absorption of solar energy reside within thylakoid membranes of chloroplasts
Figure 7.1c

7. Figure 7.2
Figure 7.2

8. Quick Check - FIVE MIN OR FEWER
1.  Plant
2.  Thylakoid
3.  Photosynthesis
4.  Organic Molecules

9. Plants as Solar Energy Converters A
Plants as Solar Energy Converters A. Solar Radiation - Only 42% of solar radiation that hits the earth’s atmosphere reaches surface; most is visible light.

10. B. Photosynthetic Pigments - Pigments found in chlorophyll absorb various portions of visible light; absorption spectrum.
1. Two major photosynthetic pigments are chlorophyll a and chlorophyll b. 2. Both chlorophylls absorb violet, blue, and red wavelengths best. 3.  Most green is reflected back; this is why leaves appear green.

11. 4. Carotenoids are yellow-orange pigments which absorb light in violet, blue, and green regions. 5. When chlorophyll breaks down in fall, the yellow-orange pigments in leaves show through.
Figure 7.3a

12. Fall Foliage Slideshow

13. C. Absorption and action spectrum - A spectrophotometer measures the amount of light that passes through a sample of pigments. 1) As different wavelengths are passed through, some are absorbed. 2) Graph of percent of light absorbed at each wavelength is absorption spectrum .

14. 3) Photosynthesis produces oxygen; production of oxygen is used to measure the rate of photosynthesis.
4) Oxygen production and, therefore, photosynthetic activity is measured for plants under each specific wavelength; plotted on a graph, this produces an action spectrum.
5) Since the action spectrum resembles absorption spectrum, this indicates that chlorophylls contribute to photosynthesis.

15. Figure 7.3b

16. D. Photosynthetic Reaction
1. In 1930 C. B. van Niel showed that O2 given off by photosynthesis comes from water and not from CO2. 2. The net equation reads:
Pg 119a

17. E. Two Sets of Reactions in Photosynthesis 1
E. Two Sets of Reactions in Photosynthesis 1. Light reactions cannot take place unless light is present. They are the energy-capturing reactions.
Pg 119b

18. b. Chlorophyl within thylakoid membranes absorbs solar energy and energizes electrons.
c. Energized electrons move down the electron transport system; energy is captures and used for ATP production.
d. Energized electrons are also taken up by NADP+, becoming NADPH.

19. 2. Calvin Cycle Reactions
a. These reactions take place in the stroma; can occur in either the light or the dark.
b. These are synthesis reactions that use NADPH and ATP to reduce CO2.
Figure 7.4

20. Week 12- Fri 10/31 1. The equation for photosynthesis. Write it!
2.  The structure of a chloroplast.  Sketch it!
3.  Compare Absorption Spectrum to Action Spectrum.  
4.  Compare the two stages of photosynthesis and their products.  Chart it!

21. Quick Practice

22. Quick Practice
grana
thylakoid
stroma O2

23. The Light Reactions 1. Two paths operate within the thylakoid membrane
                         noncyclic              and                cyclic
                          *straight line                       *in a circle
2.  Both paths use ATP, but the noncyclic also produces NADPH
3.  PHOTOPHOSPHORYLATION = ATP production

24. 1. Light hits photosystem II and exites an electron, H20
2.  The primary electron acceptor passes the electron down the ETC and generates ATP
3. Light is required for PSI, but not water, it generates NADPH

25. Something trivial.... Photosystem I and Photosystem II are named based on when they were discovered, PSI was established first.

26. Excitation of Chlorophyll by Light
When a pigment absorbs light -It goes from a ground state to an excited state, which is unstable
Excited
state
Energy of election
Heat
Photon
(fluorescence)
Chlorophyll
molecule
Ground e–
Figure A

27. (INTERIOR OF THYLAKOID)
Photosystem
Is composed of a reaction center surrounded by a number of light-harvesting complexes
Primary election
acceptor
Photon
Thylakoid
Light-harvesting
complexes
Reaction
center
Photosystem
STROMA
Thylakoid membrane
Transfer
of energy
Special
chlorophyll a
molecules
Pigment
THYLAKOID SPACE
(INTERIOR OF THYLAKOID)
Figure 10.12 e–

28. Light Harvesting Complexes
Primary election
acceptor
Photon
Thylakoid
Light-harvesting
complexes
Reaction
center
Photosystem
STROMA
Thylakoid membrane
Transfer
of energy
Special
chlorophyll a
molecules
Pigment
THYLAKOID SPACE
(INTERIOR OF THYLAKOID)
Figure 10.12 e–
Pigment molecules bound to particular proteins
Funnel the energy of photons of light to the reaction center

29. (INTERIOR OF THYLAKOID)
Electron Acceptor
Primary election
acceptor
Photon
Thylakoid
Light-harvesting
complexes
Reaction
center
Photosystem
STROMA
Thylakoid membrane
Transfer
of energy
Special
chlorophyll a
molecules
Pigment
THYLAKOID SPACE
(INTERIOR OF THYLAKOID)
Figure 10.12 e–
When a reaction-center chlorophyll molecule absorbs energy
One of its electrons gets bumped up to a primary electron acceptor

30. Thylakoid Membrane
Is populated by two types of photosystems, I and II

31. Light Reaction (Linear electron flow)
Chlorophyll excited by light absorption
E passed to reaction center of Photosystem II (protein + chlorophyll a)
e- captured by primary electron acceptor
Redox reaction  e- transfer
e- prevented from losing E (drop to ground state)
Water is split to replace e-  O2 formed

32. e- passed to Photosystem I via ETC
E transfer pumps H+ to thylakoid space
ATP produced by photophosphorylation
e- moves from PS I’s primary electron acceptor to 2nd ETC
NADP+ reduced to NADPH
MAIN IDEA: Use solar E to generate ATP & NADPH to provide E for Calvin cycle

38. Figure 10.14 NADPH e– Mill makes ATP Photon Photosystem II

39. Noncyclic Electron Flow
Is the primary pathway of energy transformation in the light reactions that produces NADPH, ATP and oxygen
Figure 10.13
Photosystem II
(PS II)
Photosystem-I
(PS I)
ATP
NADPH
NADP+
ADP
CALVIN
CYCLE
CO2
H2O O2
[CH2O] (sugar)
LIGHT
REACTIONS
Light
Primary
acceptor Pq
Cytochrome
complex PC e
P680 e– +
2 H+ Fd
reductase
Electron
Transport
chain
Electron transport chain
P700
+ 2 H+
+ H+

40. Cyclic Electron Flow
Under certain conditions photoexcited electrons take an alternative path
Only photosystem I used, only ATP produced
Primary
acceptor Pq Fd
Cytochrome
complex Pc
NADP+
reductase
NADPH
ATP
Figure 10.15
Photosystem II
Photosystem I

41. The Light Reactions and Chemiosmosis
REACTOR
NADP+
ADP
ATP
NADPH
CALVIN
CYCLE
[CH2O] (sugar)
STROMA
(Low H+ concentration)
Photosystem II
H2O
CO2
Cytochrome
complex O2 1
1⁄2 2
Photosystem I
Light
THYLAKOID SPACE
(High H+ concentration)
Thylakoid
membrane
synthase Pq Pc Fd
reductase
+ H+
NADP+ + 2H+ To
Calvin
cycle P 3 H+
2 H+
+2 H+
Figure 10.17

42. Figure 7.5
Figure 7.5

43. Indicate which system (PS1 or PS2 or BOTH)
____1.  Splits water
____2.  Produces NADPH ____3.  Has an electron transport chain
____4.  Requires light
____5.  Utilizes a primary electron acceptor
____6.  Occurs in the thylakoid
____7.  Requires the input of H20
____8.  The cyclic path ____9.  Uses chlorophyll
____10.  Releases oxygen

44. D. ATP Production --> CHEMIOSMOSIS When H20 is split, two H+ remain
 Light Reactions
   
   A.  Two Pathways
   B.  Noncyclic
   C.  Cyclic
   D.   ATP Production  -->  CHEMIOSMOSIS
           When H20 is split, two H+ remain
           These H+ are pumped from the stroma into the thylakoid
            This creates a gradient used to produce ATP from ADP
ATP is the whole point of Photosystem II and will be used to power the Light Independent Reactions (Calvin Cycle)

45. Figure 7.7
Figure 7.7

46. Both respiration and photosynthesis use chemiosmosis to generate ATP

47. Chemiosmosis is difficult to visualize. So... you get to color it!
Yay! coloring!

48. AB = ATP AC = phospholipids AD = light (energy)
A = photosystem II B = photosystem I
C = H20
D = Electron Transport Chain
E = ATP Synthase
AB = ATP
AC = phospholipids
AD = light (energy)

49. Journal

50. The Calvin Cycle Also called *The Light Independent Reactions
*The Dark Reactions
*Named after Melvin Calvin, who used a radioactive isotope of carbon to trace the reactions.

51. The Calvin Cycle FIXATION REDUCTION REGENERATION
is a series of reactions producing carbohydrates. carbon dioxide fixation, carbon dioxide reduction, and regeneration of RuBP.
FIXATION REDUCTION REGENERATION

52. B. Fixation of Carbon Dioxide
1. CO2 fixation is the attachment of CO2 to an organic compound called RuBP.
2. RuBP (ribulose bisphosphate) is a five-carbon molecule that combines with carbon dioxide.

53. 3. The enzyme RuBP carboxylase (rubisco) speeds this reaction; this enzyme comprises 20–50% of the protein content of chloroplasts, probably since it is a slow enzyme.
Calvin Cycle Animation

54. C. Reduction of Carbon Dioxide
1. With reduction of carbon dioxide, a PGA 
(3-phosphoglycerate [C3])
molecule forms.

55. 2. Each of two PGA molecules undergoes reduction to PGAL in two steps.
3. Light-dependent reactions provide NADPH (electrons) and ATP (energy) to reduce PGA to PGAL.

56. D. Regeneration of RuBP
1. Every three turns of Calvin cycle, five molecules of PGAL are used to re-form three molecules of RuBP.
2. Every three turns of Calvin cycle, there is net gain of one PGAL molecule; five PGAL regenerate three molecules of RuBP.

57. Figure 7.8
Figure 7.8

58. E. The Importance of the Calvin Cycle
1. PGAL, the product of the Calvin Cycle can be converted into all sorts of other molecules.
2. Glucose phosphate is one result of PGAL metabolism; it is a common energy molecule.

59. Figure 7.9
Figure 7.9

60. Pg 129b
Light & H2O
CO2
ADP
NADP
ATP
Pg 129b
NADPH O2
glucose

61. Journal

62. In order for photosynthesis to occur, plants must open tiny pores on their leaves called STOMATA.
Opening these pores can lead to loss of water.

63. Alternative Pathways
The Calvin Cycle is the MOST Common Pathway for Carbon Fixation. Plant Species that fix Carbon EXCLUSIVELY through the Calvin Cycle are known as C3 PLANTS. 
Plants in hot dry environments have a problem with water loss, so they keep their stomata partly closed... this results in
CO2  deficit (Used in Calvin Cycle), and the level of O2 RISES                 (as Light reactions Split Water Molecules).

64. Figure 7.10
C4 plants and CAM plants use an alternate pathway to FIX carbon dioxide from the air.
Figure 7.10

65. Figure 7.11
THE CAM PATHWAY - Plants that use the CAM Pathway open their stomata at night and close during the day.
At night, CAM Plants take in CO2 and fix into organic compounds. During the day, CO2 is released from these Compounds and enters the Calvin Cycle. Because they have their stomata open only at night, they grow slow.
Figure 7.11

66. Evolutionary Adaptations
C3 Plants:
CO2 fixed to 3-C compound  Calvin cycle
Ex. Rice, wheat, soybeans
Hot, dry days:
partially close stomata, ↓CO2
Photorespiration
↓ photosynthetic output (no sugars made)

67. C4 Plants: CO2 fixed to 4-C compound Ex. corn, sugarcane, grass
Hot, dry days  stomata close
2 cell types = mesophyll & bundle sheath cells
mesophyll : PEP carboxylase fixes CO2 (4-C), pump CO2 to bundle sheath
bundle sheath: CO2 used in Calvin cycle
↓photorespiration, ↑sugar production
WHY? Advantage in hot, sunny areas

68. C4 Leaf Anatomy

69. CAM Plants: Crassulacean acid metabolism (CAM)
NIGHT: stomata open  CO2 enters  converts to organic acid, stored in mesophyll cells
DAY: stomata closed  light reactions supply ATP, NADPH; CO2 released from organic acids for Calvin cycle
Ex. cacti, pineapples, succulent (H2O-storing) plants
WHY? Advantage in arid conditions

71. Comparison C3 C4 CAM C fixation & Calvin together
C fixation & Calvin in different cells
C fixation & Calvin at different TIMES
Rubisco
PEP carboxylase
Organic acid

72. Importance of Photosynthesis
Plant:
Glucose for respiration
Cellulose
Global:
O2 Production
Food source

73. Review of Photosynthesis

75. Photosynthesis Calvin Cycle Light ENERGY Light Reaction
involves both
Light ENERGY
Light Reaction
CO2 fixed to RuBP
stored in
in which
organic molecules
energized electrons
H2O split
pass down
Reduce NADP+ to
C3 phosphorylated and reduced
ETC
NADPH
O2 evolved
by mechanism of
using
to form
regenerate RuBP
ATP
G3P
chemiosmosis
using
in process called
glucose & other carbs
photophosphorylation

76. Compare
LIGHT REACTIONS
Calvin cycle

77. Mitochondria
chloroplast

78. Comparison RESPIRATION PHOTOSYNTHESIS Plants + Animals
Needs O2 and food
Produces CO2, H2O and ATP, NADH
Occurs in mitochondria membrane & matrix
Oxidative phosphorylation
Proton gradient across membrane
Plants
Needs CO2, H2O, sunlight
Produces glucose, O2 and ATP, NADPH
Occurs in chloroplast thylakoid membrane & stroma
Photorespiration
Proton gradient across membrane