Essential Question:How do plants harness the suns energy?
The process of photosynthesis is a chemical reaction that converts light energy into chemical energy.
Photo = lightSynthesis = to make
It is the most important chemical reaction on our planet.
• Organisms that carry out photosynthesis are called •producers or autotrophs
- producers are the basis of all of Earth’s food chains
•occurs in chloroplasts
- the energy in the light is absorbed by the chlorophyll and converted to chemical energy
Plants
Algae
Some Bacteria
Discuss question 6 with
your partner then answer it.
Thylakoids found inside the chloroplast contain the pigment chlorophyll
. thylakoids
Different wavelengths of visible light are seen by the human eye as different colors.
WHYWHY ARE ARE PLA PLANTS NTS GREGREEN?EN?
Gammarays
X-rays UV Infrared Micro-waves
Radiowaves
Visible light
Wavelength (nm)
Why are plants green?
Reflected lig
ht
Transmitted light
• Chloroplasts absorb light energy and convert it to chemical energy
LightReflected
light
Absorbedlight
Transmittedlight
Chloroplast
THE COLOR OF LIGHT SEEN IS THE COLOR NOT ABSORBED
• As the chlorophyll in leaves decays in the Fall, the green color fades and is replaced by the oranges and reds of carotenoids
-Grana- structures inside the chloroplast that are made of stacks of thylakoids.
grana
thylakoids
Stroma – the fluid filled space outside of the grana.
stroma contains enzymes necessary to convert CO2 into sugar which stores energy
.
stroma
grana
thylakoids
The Balanced Photosynthesis Equation
CO2 H2O C6H12O
6
O2LighLightt
+ +6 6 6
Reactants
Products
stroma
grana
thylakoids
Discuss with your partner…
Where the chlorophyll is
found
Discuss with your partner…What we call
stacks of thylakoids
Discuss with your partner…
What is the term used to describe
the fluid filled space
Discuss with your partner…Where in the chloroplast is light captured
Discuss and answer
questions 11-14 with your
partner
How are the thylakoids, grana,
and stroma related?
• Bring In•1. light•2. Reactants
•CO2
•H2O• Waste Product
•O2
• Makes and uses the product•Sugar (glucose)
6CO2 6H2O C6H12O6 6O2lightenergy+ ++
•Two major parts
•Light Reactions•Light Independent reactions (Calvin Cycle)
- capture energy in sunlight and transfer it to chemical energy
- take place in thylakoid membrane of a chloroplast
- Chlorophyll is found in the thylakoid disks and they absorbs energy from sunlight
Light reaction1.Light is absorbed by chlorophyll in the thylakoid2.enzymes split H2O and oxygen is released3.energy from light is stored in ATP & NADPH
Discuss question 20 with your
partners, then write your answer
on your paper.
Discuss question 21 with your
partners, then write your answer
on your paper.
• Two connected photosystems collect photons of light and transfer the energy to chlorophyll electrons
• The excited electrons are passed from the primary electron acceptor to the electron transport chains• Their energy ends up in ATP and NADPH
22. In the light reactions, electron In the light reactions, electron
transport chains powers ATP production and transport chains powers ATP production and stores energy in NADPH which is used to stores energy in NADPH which is used to power the Calvin cycle.power the Calvin cycle.
The O2 liberated by photosynthesis is made from the oxygen in water (H+ and e-)
23. Plants produce O2 gas by
splitting (breaking) H2O molecule
24. ATP- energy is released when a
phosphate group is removed- ADP is then produced (can be converted back to ATP)
- Function: the chemical energy used for most cell processes
25. NADP+• NADPH is formed (functions like ATP = energy) when electrons are added to NADP+
• FUNCTION: the major electron carrier during photosynthesis
26. Carrier molecules
supply electrons
• NADPH is an unstable molecule that stores chemical energy for the cell
The addition of a phosphate group to an organic molecule. Phosphorylation is important for many processes in living cells. ATP is formed during cell respiration from ADP by phosphorylation, in the mitochondria of eukaryotic cells and the chloroplasts of plant cells (photosynthetic phosphorylation).
1. Write the chemical equation for the light reaction.
2. Which products will be used in the next phase of photosynthesis? (page 226)
3. Why cant energy be stored as ATP and NADPH?
4. What is the second phase of photosynthesis?
5. What is another name for the second phase of photosynthesis?
1. Light reaction•Light is absorbed by chlorophyll in the thylakoid - enzymes split H2O and oxygen is released - energy from light is stored in ATP & NADPH
Reactants Products
Light + H20
Occurs in the thylakoid membrane
of the chloroplast
O2 + ATP + NADPH
Can occur during the light or the dark
Discuss questions 29
with your partner then
answer it.
• The Calvin Cycle takes place in the stroma of the chloroplast
• Uses CO2 from the atmosphere and energy from the light reactions stored in ATP & NADPH
Steps of Photosynthesis
• The DARK Reactions = Calvin Cycle
• CO2 from atmosphere is joined with the energy stored in ATP and NADPH to form glucose
• Glucose can be converted into other molecules like cellulose, which is used for structural support in plant cells.
• Why store energy from the sun as sugar and not ATP?
• - ATP is an unstable compound – it doesn’t last a long time.
• - sugar (glucose) is stable and can store the energy for a long period of time.
• - sugar can be used to build even larger storage molecules (polysaccharides)
•
• A Photosynthesis Road Map
Chloroplast
Light
Stack ofthylakoids ADP
+ P
NADP
Stroma
Lightreactions
Calvincycle
Sugar used for
Cellular respiration
Cellulose Starch
Other organic compounds
1. Light reaction (depends on light)• Captures sunlight• Breaks down water molecules to produce
electrons to form ATP and NADPH• Produces oxygen as a waste product
2. Calvin Cycle (does not directly depend on light)
• Uses ATP, NADPH (from light reaction), and CO2 to make glucose
• Glucose is the product in the Calvin cycle
It's not that It's not that easy bein' easy bein' green… but it green… but it is essential for is essential for life on earth!life on earth!
Glue the photosynthesis
concept map onto page 64 of your
notebook
Photosynthesis
Light-DependentReactions
Water &Energy from
Sunlight
Thylakoid Membranes
ATP NADPH Oxygen Chloroplast
Stroma
Calvin Cycle
ATP NADPH
Glucose(High Energy
Sugars)
Includes
Use Takes place in
To Produce
Takes Place in
Of
Uses
To Produce
CarbonDioxide