Chapter 8 - Photosynthesis
Overview of Photosynthesis and Respiration3. PHOTOSYNTHESIS5.
RESPIRATION1. SUN2. LIGHT ENERGY4. CHEMICAL ENERGY6. ATP (CELL
Energy Formation in CellsEnergy for LifeATPADP and POrganic
Compounds & OxygenCarbon Dioxide & Water
Overview of Energy FormationPlants use sunlight to make food
(Carbohydrates, sugars, etc) This is stored energy thoughThen
cellular respiration occurs in the mitochondria which takes the
food and breaks it down into usable energy, or ATP
What is ATP?Adenosine triphosphate- a chemical compound that can
store and release energy
How does ATP work?The energy in ATP lies in the bond between the
2nd and 3rd phosphateIf you break the bond and release the
phosphate energy is released which leaves you with ADPIf you add a
phosphate to ADP you store energyEnergy
Where does it occur?In plants that are able to capture sunlight
to make their own food (aka autotrophs.)The actual process occurs
inside a cells chloroplasts.
What does it need?
CARBON DIOXIDE (CO2)
What happens? (photosynthesis equation)6CO2 +6H2O +ENERGYC6H12O6
+6O2 Carbon DioxideWaterCarbohydratesOxygenSunlight
How does happen?The process of photosynthesis does not happen
all at once. It is a very long process that is broken into 3
Stage 1 Light ReactionsLight is absorbed from the sun by the
H2O is taken into the cell as well.
The light energy is used to split H20 into 3 separate parts (H,
O2, and electrons.)
How does it work?Inside the chloroplasts are disk-shaped
structures called thylakoids that contain different pigments.
How does it work?Pigments do the actual absorbing of light.
a) Chlorophylls absorb red and blue light (produce green
b) Carotenoids absorb other colors(produce yellow and orange
How does it work?Once the sunlight is captured it is used to
split water (H20) into Hydrogen (H), Oxygen gas (O2), and free
Oxygen gas (O2) is free to leave the plant and this is what
animals use to breathe.
Stage 2 Energy StorageFree electrons are passed from thylakoid
to thylakoid until they reach an ADP molecule and turn it into an
Hydrogen (H) molecules are passed from protein to protein until
they reach a NADP+ molecule and then they become an NADPH.
How does it work?As electrons continuously get passed on this
process is known as the electron transport chain.
Stage 3 Dark ReactionsThe newly formed ATP and NADPH power the
formation of carbohydrates, sugars, and starches.
This is done by using CO2 as the starting material.
How does it work?Carbon Dioxide (CO2) enters the cell from the
atmosphere and undergoes a process called the Calvin Cycle which
creates simple sugars.
Step 1A Carbon Dioxide molecule is joined to a 5-carbon compound
called RuBP (ribulose bisphosphate) to create a 6-carbon
Step 2The newly formed 6-carbon compound immediately splits into
two 3-carbon compounds.
Step 3One of the new 3-carbon compounds is used to make the
initial 5-carbon compound that originally joined to the Carbon
Step 4The second 3-carbon compound is used to make
carbohydrates, sugars, and starches.
Summary of Stages
Factors that affect it?Light intensityAmount of CO2
If any of these factors increase the photosynthesis process also
increases and vice versa.
PhotosynthesisH2OCO2O2C6H12O6Light ReactionDark ReactionLight is
AdsorbedBy ChlorophyllWhich splitswaterChloroplastATP
andNADPH2ADPNADPCalvin CycleEnergyUsed Energy and is
PhotosynthesisCapturing Energy from the Sun*Using energy to make
ATP and NADPH*Using ATP and NADPH to make carbohydrates, sugars,
and starches ** Light Dependent Reactions* Light Independent
Reactions (Calvin Cycle)
Education is light, lack of it darkness.--Russian Proverb
Education is the movement from darkness to light.--Bloom