1. Photosynthesis Life Is Solar Powered!

2. What Would Plants Look Like On Alien Planets?

3. Why Would They Look Different?
Different Stars Give off Different types of light or Electromagnetic Waves
The color of plants depends on the spectrum of the star’s light, which astronomers can easily observe. (Our Sun is a type “G” star.)

4. Anatomy of a Wave Wavelength
Is the distance between the crests of waves
Determines the type of electromagnetic energy

5. Electromagnetic Spectrum
Is the entire range of electromagnetic energy, or radiation
The longer the wavelength the lower the energy associated with the wave.

6. Visible Light
Light is a form of electromagnetic energy, which travels in waves
When white light passes through a prism the individual wavelengths are separated out.

7. Visible Light Spectrum
Light travels in waves
Light is a form of radiant energy
Radiant energy is made of tiny packets of energy called photons
The red end of the spectrum has the lowest energy (longer wavelength) while the blue end is the highest energy (shorter wavelength).
The order of visible light is ROY-G-BIV
This is the same order you will see in a rainbow b/c water droplets in the air act as tiny prisms

8. Chloroplast – Where the Magic Happens!+
H2O
CO2
Energy
ATP and
NADPH2
Which splits
water
Light is Adsorbed By
Chlorophyll
Calvin Cycle
ADP
NADP
Chloroplast
Used Energy and is recycled. O2 +
C6H12O6
Light Reaction
Dark Reaction
6 CO H2O + Light energy  C6H12O6 + 6 O2 + 6 H2 O

9. Light Options When It Strikes A Leaf
Reflected
Chloroplast
Absorbed
light
Granum
Transmitted
Figure 10.7
Reflect – a small amount of light is reflected off of the leaf. Most leaves reflect the color green, which means that it absorbs all of the other colors or wavelengths.
Absorbed – most of the light is absorbed by plants providing the energy needed for the production of Glucose (photosynthesis)
Transmitted – some light passes through the leaf

10. Photosynthesis Overview
Concept Map
Photosynthesis
includes
Light
dependent
reactions
Light
independent
reactions
occurs in
uses
uses
occur in
Light
Energy
Thylakoid
membranes
Stroma
ATP
NADPH
to produce of
to produce
ATP
NADPH O2
Chloroplasts
Glucose

11. Anatomy of a Leaf Figure 10.3 Leaf cross section Vein Mesophyll CO2 O2
Stomata

13. Chloroplast

14. Chloroplast Are located within the palisade layer of the leaf
Stacks of membrane sacs called Thylakoids
Contain pigments on the surface
Pigments absorb certain wavelenghts of light
A Stack of Thylakoids is called a Granum
Chloroplast
Mesophyll
5 µm
Outer
membrane
Intermembrane
space
Inner
Thylakoid
Granum
Stroma
1 µm

15. Pigments Are molecules that absorb light
Chlorophyll, a green pigment, is the primary absorber for photosynthesis
There are two types of cholorophyll
Chlorophyll a
Chlorophyll b
Carotenoids, yellow & orange pigments, are those that produce fall colors. Lots of Vitamin A for your eyes!
Chlorophyll is so abundant that the other pigments are not visible so the plant is green…Then why do leaves change color in the fall?

16. Color Change
In the fall when the temperature drops plants stop making Chrlorophyll and the Carotenoids and other pigments are left over (that’s why leaves change color in the fall).

17. Wavelength of light (nm)
The absorption spectra of three types of pigments in chloroplasts
Three different experiments helped reveal which wavelengths of light are photosynthetically important. The results are shown below.
EXPERIMENT
RESULTS
Absorption of light by
chloroplast pigments
Chlorophyll a
(a) Absorption spectra. The three curves show the wavelengths of light best absorbed by three types of chloroplast pigments.
Wavelength of light (nm)
Chlorophyll b
Carotenoids
Figure 10.9

18. The action spectrum of a pigment
Profiles the relative effectiveness of different wavelengths of radiation in driving photosynthesis
(measured by O2 release)
Rate of photosynthesis
Action spectrum. This graph plots the rate of photosynthesis versus wavelength. The resulting action spectrum resembles the absorption spectrum for chlorophyll a but does not match exactly (see part a). This is partly due to the absorption of light by accessory pigments such as chlorophyll b and carotenoids.
(b)

19. The action spectrum for photosynthesis
Was first demonstrated by Theodor W. Engelmann
400
500
600
700
Aerobic bacteria
Filament
of alga
Engelmann‘s experiment. In 1883, Theodor W. Engelmann illuminated a filamentous alga with light that had been passed through a prism, exposing different segments of the alga to different wavelengths. He used aerobic bacteria, which concentrate near an oxygen source, to determine which segments of the alga were releasing the most O2 and thus photosynthesizing most.
Bacteria congregated in greatest numbers around the parts of the alga illuminated with violet-blue or red light. Notice the close match of the bacterial distribution to the action spectrum in part b.
(c)
Light in the violet-blue and red portions of the spectrum are most effective in driving photosynthesis.
CONCLUSION

20. Absorption of chlorophylls a and b at various wavelengths in the visible light spectrum

21. Pigment Molecules that absorb specific wavelengths of light
Chlorophyll absorbs reds & blues and reflects green
Xanthophyll absorbs red, blues, greens & reflects yellow
Carotenoids reflect orange

22. Chlorophyll Green pigment in plants Traps sun’s energy
Sunlight energizes electron in chlorophyll

23. PHOTOSYNTHESIS
Comes from Greek Word “photo” meaning “Light” and “syntithenai” meaning “to put together”
Photosynthesis puts together sugar molecules using water, carbon dioxide, & energy from light.

24. Happens in two phases Light-Dependent Reaction
Converts light energy into chemical energy
Light-Independent Reaction
Produces simple sugars (glucose)
General Equation
6 CO2 + 6 H2O  C6H12O6 + 6 O2

25. First Phase Requires Light = Light Dependent Reaction
Sun’s energy energizes an electron in chlorophyll molecule
Electron is passed to nearby protein molecules in the thylakoid membrane of the chloroplast

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. Two Photosystems
Photosystem II: Clusters of pigments boost e- by absorbing light w/ wavelength of ~680 nm
Photosystem I: Clusters boost e- by absorbing light w/ wavelength of ~760 nm.
Reaction Center: Both PS have it. Energy is passed to a special Chlorophyll a molecule which boosts an e-

28. A mechanical analogy for the light reactions
Mill
makes
ATP e–
Photon
Photosystem II
Photosystem I
NADPH
Figure 10.14 

29. ATP Adenosine Triphosphate
Stores energy in high energy bonds between phosphates

30. NADPH Made from NADP+; electrons and hydrogen ions
Made during light reaction
Stores high energy electrons for use during light-Independent reaction (Calvin Cycle)

31. Figure 10.5 H2O CO2 [CH2O] O2 (sugar) Light LIGHT REACTIONS CALVIN
CYCLE
Chloroplast
[CH2O]
(sugar)
NADPH
NADP 
ADP
+ P O2
Figure 10.5
ATP

32. PART II LIGHT INDEPENDENT REACTION Also called the Calvin Cycle
No Light Required
Takes place in the stroma of the chloroplast
Takes carbon dioxide & converts into sugar
It is a cycle because it ends with a chemical used in the first step

33. Begins & Ends
The Calvin Cycle begins with the products of the light reaction.
(the Calvin Cycle uses ATP & NADPH)
CO2 is added and ends in the production of sugar (GLUCOSE)
Formula: C6H12O6

34. The Calvin cycle Figure 10.18 Input Light 3 CO2 CALVIN CYCLE
(G3P)
Input
(Entering one
at a time)
CO2 3
Rubisco
Short-lived intermediate
3 P P
Ribulose bisphosphate (RuBP)
3-Phosphoglycerate
6 P 6
1,3-Bisphoglycerate
6 NADPH
6 NADPH+
Glyceraldehyde-3-phosphate
6 ATP
ATP
3 ADP
CALVIN
CYCLE 5 1
G3P (a sugar) Output
Light
H2O
LIGHT REACTION
ATP
NADPH
NADP+
ADP
[CH2O] (sugar)
CALVIN CYCLE
Figure 10.18 O2
6 ADP
Glucose and other organic compounds
Phase 1: Carbon fixation
Phase 3: Regeneration of the CO2 acceptor (RuBP)
Phase 2: Reduction

35. Chloroplast – Where the Magic Happens!+
H2O
CO2
Energy
ATP and
NADPH2
Which splits
water
Light is Adsorbed By
Chlorophyll
Calvin Cycle
ADP
NADP
Chloroplast
Used Energy and is recycled. O2 +
C6H12O6
Light Reaction
Dark Reaction
6 CO H2O + Light energy  C6H12O6 + 6 O2 + 6 H2 O

36. Cellular Respiration

38. How Cells Harvest Chemical Energy
Introduction to Cell Metabolism
Glycolysis
Aerobic Cell Respiration
Anaerobic Cell Respiration

39. BREATHING Breathing and Cell Respiration are related
CO2
Lungs
Muscle cells carrying out
CO2
Bloodstream O2
CELLULAR RESPIRATION
Sugar + O2  ATP + CO2 + H2O

40. Cellular Respiration uses oxygen and glucose to produce
Carbon dioxide, water, and ATP.
Glucose
Oxygen gas
Carbon dioxide
Water
Energy

41. How efficient is cell respiration?
Energy released from glucose banked in ATP
Energy released from glucose (as heat and light)
Gasoline energy converted to movement
100%
About 40%
25%
Burning glucose in an experiment
“Burning” glucose in cellular respiration
Burning gasoline in an auto engine

42. Reduction and Oxidation OILRIG
Oxidation is losing electrons
Reduction is gaining electrons
Loss of hydrogen atoms
Energy
Glucose
Gain of hydrogen atoms
Glucose gives off energy and is oxidized

43. Glycolysis Glucose General Outline No Oxygen Anaerobic Oxygen Aerobic
Pyruvic Acid
Transition Reaction
Fermentation
Krebs Cycle
ETS
36 ATP

44. Glycolysis
Where? The cytosol
What? Breaks down glucose to pyruvic acid

46. Glycolysis Energy In: 2 ATP Energy Out: 4 ATP NET 2 ATP
Steps – A fuel molecule is energized, using ATP.
Glucose 1 3
Step
Glycolysis 1
Glucose-6-phosphate 2
Fructose-6-phosphate
Energy In: 2 ATP 3
Fructose-1,6-diphosphate
Step A six-carbon intermediate splits into two three-carbon intermediates. 4 4
Glyceraldehyde-3-phosphate (G3P) 5
Step A redox reaction generates NADH. 5
1,3-Diphosphoglyceric acid (2 molecules) 6
Steps – ATP and pyruvic acid are produced.
3-Phosphoglyceric acid (2 molecules)
Energy Out: 4 ATP 6 9 7
2-Phosphoglyceric acid (2 molecules) 8
2-Phosphoglyceric acid (2 molecules)
NET 2 ATP 9
Pyruvic acid
(2 molecules per glucose molecule)

47. General Outline of Aerobic Respiration
Glycolysis
Transition Reaction
Krebs Cycle
Electron Transport System

48. Transition Reaction
Each pyruvic acid molecule is broken down to form CO2 and a two-carbon acetyl group, which enters the Krebs cycle
Pyruvic Acid
Acetyl CoA

49. General Outline of Aerobic Respiration
Glycolysis
Transition Reaction
Krebs Cycle
Electron Transport System

50. Krebs Cycle
Where? In the Mitochondria
What? Uses Acetyl Co-A to generate ATP, NADH, FADH2, and CO2.

52. Krebs Cycle

53. Krebs Cycle

54. General Outline of Aerobic Respiration
Glycolysis
Krebs Cycle
Electron Transport System

56. ELECTRON TRANSPORT CHAIN
Electron Transport System
Protein complex
Intermembrane space
Electron carrier
Inner mitochondrial membrane
Electron flow
Mitochondrial matrix
ELECTRON TRANSPORT CHAIN
ATP SYNTHASE
Figure 6.12

57. Electron Transport System
For each glucose molecule that enters cellular respiration, chemiosmosis produces up to 38 ATP molecules

58. Overview of Aerobic Respiration

59. Fermentation
Requires NADH generated by glycolysis.
Where do you suppose these reactions take place?
Yeast produce carbon dioxide and ethanol
Muscle cells produce lactic acid
Only a few ATP are produced per glucose

60. Fermentation

61. Fermentation in the Absence of Oxygen
Fermentation When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue.
Lactic Acid Fermentation In lactic acid fermentation, pyruvate is converted to lactate.

62. Each molecule of glucose can generate molecules of ATP in aerobic respiration but only 2 ATP molecules in respiration without oxygen (through glycolysis and fermentation).