Transcript Photosynthesis

Photosynthesis
Biology 1114
Autotrophs “Self Feeders”
Photosynthesize
Plants
Algae / Protists
Some Bacteria
A Large Proportion of Photosynthesis (40%-50%)
Takes Place in the Oceans of the World and is
Carried Out by Plankton
Photosynthesis “The conversion of light
energy from the sun into chemical
energy”
• Light Energy is converted into Chemical
Energy
• Organisms trap the Sun’s Energy to Build
Carbohydrates
chlorophyll
6CO2 + 12 H2O + Light Energy------------------------> C6H12O6 + 6O2 + 6 H2O
enzymes
Photosynthesis
Enables Societies
to Function and
is the Sole Means
of Sustaining
Life
Utilization of Photosynthetic
Sugars
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Wood
Fibers
Stored Carbohydrates
Amino Acids
Clothing
Shelter
Food
Photosynthesis
Provides
Consumers with
Energy Through
the Ingestion of
Producers
Ozone Protects us
from UV Radiation
from the Sun
As you know, the
increase in UV
radiation due to
ozone loss is very
damaging to
complex
molecules, which
are an essential
ingredient for life
as we know it.
Skin Cancer
Scientists say ozone layer recovery may not be detectable
for as many as 45 years.
Fossil Fuels
Photosynthesis
chlorophyll
6CO2 + 12 H2O + Light Energy------------------------> C6H12O6 + 6O2 + 6 H2O
enzymes
Photosynthesis
• Energy of the sun is transformed into
chemical energy stored in food
• Not 100% efficient
• Not all sunlight falls on producers
• Some absorbed energy is subsequently
released and lost
Photosynthesis
chlorophyll
6CO2 + 12 H2O + Light Energy------------------------> C6H12O6 + 6O2 + 6 H2O
enzymes
Photosynthesis changes two low energy molecules
(Carbon Dioxide and Water) into a high energy molecule
(Sugar).
Von Helmont
Experiment
Jon Baptista von Helmont, a 17th century
Flemish physician started getting a handle
on what happens when plants grow in the
soil with his "tree experiment." He was
trying to measure how soil matter was
displaced when plants grow. To do this, he
planted a willow tree in a large earthen tub.
He planted a 5-pound sprig into 200 pounds
of soil. The tub was then covered except for
a small hole for the tree trunk and one for
watering.
Five years later, the tree weighed 164
pounds. Von Helmont reasoned if the tree
had picked up the difference between 5
pounds and 164 pounds, then the soil in the
tub should weigh only 41 pounds. The
results proved him wrong! After oven
drying the soil, he'found the 200 pounds of
soil had only lost 2 ounces.
Where Does Photosynthesis Occur?
Light Dependent Reactions Require Sunlight to
Convert Light Energy into Chemical Energy
This Chemical Energy is Stored in ATP and NADPH
The Thylakoid Membranes contain all
the pigments and all the enzymes
necessary for the light phase of
photosynthesis.
Light Independent
Reactions Do Not
Require Sunlight
They Assemble
Sugars by Using
ATP and NADPH
The fluid in the stroma contains most of the
enzymes necessary for the dark phase of
photosynthesis
Necessary Molecules of Matter
• Carbon Dioxide
– .035%
– Diffuses through
Stomata
– Removed by
Photosynthesis
– Returned by
Respiration
Necessary Molecules of Matter
• Water
– Taken up through Roots
– <1% used by Photosynthesis
– >99% lost via Transpiration
Light
• Exhibits Properties of Both waves and Particles of
Energy
• Electromagnetic Spectrum
• Visible Light is Involved in Photosynthesis
High Energy
Low Energy
Electromagnetic Spectrum
High Energy
Low Energy
Gamma Rays
X-Rays
Ultra Violet
Visible Light
Infrared
Microwaves
Radio Waves
Short Wavelength
Long Wavelength
Visible Light (Roy G. Biv)
High Energy
Low Energy
Violet
Indigo
Blue
Green
Yellow
Orange
Red
Short Wavelength
Long Wavelength
Light Energy is Absorbed by Pigment Molecules Each
Pigment Has a Characteristic Absorption Spectrum
The Reactions of Photosynthesis
1. Photosynthesis begins with the lightdependent reactions.
2. Light-dependent reactions are followed by
light-independent reactions
Essentials and General Overview
Summation of Light Dependent Rxn
Do What?
• During the light-dependent reactions
1. Light Energy is Absorbed
2. Water is Split
3. ATP and NADPH is Formed
Note: At this point Carbon Dioxide has not been used
and no sugars have been produced.
Light Energy from the Sun is Transferred to Chlorophyll in Plants
Chlorophyll Passes Energy Down Through the Electron Transport Chain
Providing Energy to do Two Things
Split Water
O2 is Released
2H+ and NADPH
P + ADP  ATP
For Use in the LightIndependent
Reaction
Light Independent Reactions or
Calvin Cycle
• Stroma
• Light or Dark
• Requires
1.
2.
3.
4.
5.
Carbon Dioxide
Hydrogen Protons and Electrons
ATP
Enzymes
RUBP
Do What?
• During the light-independent reactions
1. Carbon Dioxide and Hydrogen
Combine to Make Sugar
2. Sugar Contains High Energy Bonds
3. Process Occurs by Phosphorylation
Note: The two reactions (Light and Dark) are
complementary to one another.
Essentials of Photosynthesis
• Two Reactions Complete the Process
• Carbon Dioxide Combines with Hydrogen Atoms
from Water to Make Sugar Molecules
• Some of the energy that was initially absorbed by
the plant in the form of sunlight, and which was
temporarily stored in the bonds of ATP (and
NADPH) ends up stored in the bonds of the sugar
molecules. Since it utilizes the chemical energy in
ATP and NADPH, it does not require sunlight
Essentials of Photosynthesis
• This is a complex cycle of mostly adding or
removing phosphate (phosphorylation) and
moving electrons in chemical reactions.
• The two reactions (Light and Dark) are
complementary of one another.