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Photosynthesis Life Is Solar Powered!

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Title: Photosynthesis Life Is Solar Powered!


1
PhotosynthesisLife 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 stars 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
Light Options When It Strikes A Leaf
  • 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

9
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10
Photosynthesis Overview
Concept Map
Photosynthesis
includes
Light independent reactions
Light dependent reactions
occurs in
uses
occur in
uses
Thylakoid membranes
Light Energy
Stroma
NADPH
ATP
to produce
to produce
of
ATP
NADPH
O2
Chloroplasts
Glucose
11
Anatomy of a Leaf
12
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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

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
    greenThen 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 (thats why leaves
    change color in the fall).

17
  • The absorption spectra of three types of pigments
    in chloroplasts

18
  • The action spectrum of a pigment
  • Profiles the relative effectiveness of different
    wavelengths of radiation in driving photosynthesis

19
  • The action spectrum for photosynthesis
  • Was first demonstrated by Theodor W. Engelmann

20
Chlorophyll
  • Chlorophyll a
  • Is the main photosynthetic pigment
  • Chlorophyll b
  • Is an accessory pigment

21
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.

22
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

23
First Phase
  • Requires Light Light Dependent Reaction
  • Suns energy energizes an electron in chlorophyll
    molecule
  • Electron is passed to nearby protein molecules in
    the thylakoid membrane of the chloroplast

24
Excitation of Chlorophyll by Light
  • When a pigment absorbs light
  • It goes from a ground state to an excited state,
    which is unstable

25
  • If an isolated solution of chlorophyll is
    illuminated
  • It will fluoresce, giving off light and heat

26
ETC
  • Electron from Chlorophyll is passed from protein
    to protein along an electron transport chain
  • Electrons lose energy (energy changes form)
  • Finally bonded with electron carrier called NADP
    to form NADPH or ATP
  • Energy is stored for later use

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

29
Photosystem
  • A photosystem
  • Is composed of a reaction center surrounded by a
    number of light-harvesting complexes

30
Where those electrons come from
  • Water
  • Electrons from the splitting of water
    (photolysis) supply the chlorophyll molecules
    with the electrons they need
  • The left over oxygen is given off as gas

31
The Splitting of Water
  • Chloroplasts split water into
  • Hydrogen and oxygen, incorporating the electrons
    of hydrogen into sugar molecules

32
High Quality H2O
  • Photolysis Splitting of water with light energy
  • Hydrogen ions (H) from water are used to power
    ATP formation with the electrons
  • Hydrogen ions (charged particle) actually move
    from one side of the thylakoid membrane to the
    other
  • Chemiosmosis Coupling the movement of Hydrogen
    Ions to ATP production

33
  • Animation takes a min. to loadbe patient
  • Animation II Does not take as long to load but
    it is not as good

34
  • The light reactions and chemiosmosis the
    organization of the thylakoid membrane

35
Vocabulary Review
  • Light-Dependent
  • Pigment
  • Chlorophyll
  • Electron Transport Chain
  • ATP
  • NADPH
  • Photolysis
  • Chemiosmosis

36
Light-Dependent
  • Converts light into chemical energy (ATP NADPH
    are the chemical products). Oxygen is a
    by-product

37
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

38
Chlorophyll
  • Green pigment in plants
  • Traps suns energy
  • Sunlight energizes electron in chlorophyll

39
Electron Transport Chain
  • Series of Proteins embedded in a membrane that
    transports electrons to an electron carrier

40
ATP
  • Adenosine Triphosphate
  • Stores energy in high energy bonds between
    phosphates

41
NADPH
  • Made from NADP electrons and hydrogen ions
  • Made during light reaction
  • Stores high energy electrons for use during
    light-Independent reaction (Calvin Cycle)

42
Chemiosmosis
  • The combination of moving hydrogen ions across a
    membrane to make ATP

43
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44
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

45
Begins Ends
  • The Calvin Cycle begins and ends with RuBP
  • CO2 is added to RuBP fixing the CO2 in a
    compound
  • One compound made along the way is PGAL
  • PGAL can be made into sugars or RuBP
  • Calvin Cycle uses ATP NADPH

46
  • The Calvin cycle

Phase 1 Carbon fixation
Phase 3Regeneration ofthe CO2 acceptor(RuBP)
Phase 2Reduction
47
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 CO2 12 H2O Light energy ? C6H12O6 6 O2
6 H2 O
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