Download the reactions of photosynthesis that are directly dependent upon

Energy and Photosynthesis
• What is Energy? – Ability to do work…..ughh…
• Kinetic Energy? – Energy in Action
– Examples
• Potential Energy? – Stored Energy
– Examples
• What is the Conservation of Energy?
– ENERGY CANNOT BE CREATED OR DESTROYED!
Adenosine Tri Phosphate (ATP)
Adenine
Who uses it?
Ribose
3 Phosphate groups
ADP
and
Adenosine diphosphate (ADP) + Phosphate
ATP
Adenosine triphosphate (ATP
Photosynthesis
Goal is to capture
kinetic light energy and
convert it to stored
Potential energy in the
form of GLUCOSE
• Equation
6CO2 + 6H20  C6H12O6 + 6O2
Electromagnetic Spectrum
• Light is a form of kinetic energy called
Electromagnetic radiation
– Travels in waves (and particles)
– Different wavelengths give the energy different
properties
• Blue light has more energy than red light (its
faster for a small wave to move than a long wave---think of jumping rope!)
Plants and Light
• Visible light = small part of
electromagnetic spectrum
• Sunlight is a mixture of all colors of
light. Each color of light has a different
wavelength, and thus a different
amount of energy.
• Plants only use visible wavelengths of
light.
Chloroplasts
Parts of Chloroplast
• Chloroplast: Site of photosynthesis in
eukaryotic cells.
• Thylakoids: Disk shaped membranes
containing photosynthetic pigments.
Site of light dependent reactions.
• Grana: Stacks of thylakoids.
• Stroma: Fluid filled space surrounding
grana. Site of light independent
reactions.
PHOTOSYNTHESIS
NADP+
ADP + P
Calvin
Cycle
LightDependent
Reactions
ATP
NADPH
Light Dependent Reactions
• All the reactions of photosynthesis that
are directly dependent upon light are
known as the light dependent reactions.
• The light dependent reactions occur in
the part of the cell known as the
thylakoids (Stacks of thylakoids are
known as grana.).
• Many chlorophyll molecules are found
embedded into the membranes of the
thylakoids.
• The purpose of the light reactions is to
convert light energy into chemical
energy in the form of ATP & NADPH.
• ATP & NADPH are energy carriers.
– ATP carries energy
•
– NADPH carries high energy electrons and
hydrogen ions
2 Parts to Light Reactions
• Photosystem II
– Happens 1st
– Part of light reactions that ultimately
generates ATP molecules
• Photosystem I
– Happen 2nd
– Part of light reactions that ultimately generate
NADPH molelecules
How the Photosystems work
• Electrons (from water) exited by particles of light
(photons)
• Exited electrons used to generate ATP and NADPH
• See handout for how it works.
• Big idea is knowing what each photosystem does.
• ALL ABOUT TRANSFERING ENERGY OVER TO
CALVIN CYCLE!!!
NADPH
H+ (from water molecule)
Actively transported across
thylakoid membrane
e-
ATP
H+
ADP + P
Light Photon
e-
H+
ATP
Synthase
Electrons Exited
e-
Light Photon
H2O
e-
eH+
Chlorophyll
Photosystem I
H+
Chlorophyll
Photosystem II
H+
H+ H+
H+
H+
e-
e-
ewaste
e-
(NADP+) picks up
high energy
electrons
e-
H+
O2
Electrons Exited
Electrons removed from H20 are
exited in Photosystem II. The
electron flow down the transport
chain provides energy for the
transport of hydrogen ions (creating
concentration gradient which
ultimately drive the production of
ATP.
H+
H+
H+
H+
In Photosystem I, the
electrons get energized by a
photon of light (again) and
travel down another transport
chain where they become
part of An NADPH molecule.
The light reactions and chemiosmosis
Calvin Cycle (aka Dark Reactions
aka light independent reactions)
• All reactions of photosynthesis not directly
dependent upon light are known as the light
independent reactions. They occur whether
there is light present or not.
• The light independent reactions occur in the
part of the chloroplast known as the stroma.
• The purpose of the light independent
reactions is to take the energy from ATP and
energized electrons and hydrogen ions from
NADPH and add them to CO2 to make glucose
or sugar.
•
The purpose of the light independent reactions (Calvin cycles) is to take the energy from ATP and energized
electrons and hydrogen ions from NADPH and add them to CO2 to make glucose or sugar.