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