10/28-29/13

Starter:1.What is photosynthesis?

2.10/29- What structure in the plant contains chlorophyll?

10/28-29/13

Photosynthesis notes

Application/Connection/Exit:

Notes and ws

Practice: Questions:1What is photosynthesis?

2. What organisms conduct photosynthesis?

3. If plants get their energy/food from photosynthesis, how do animals get their energy/food

Photosynthesis notes 77 78

October 24, 2013

AGENDAB.9 B.

I will Compare the reactants and products of

photosynthesis and cellular

respiration in terms of energy and matter while

completing notes.

1 Starter2. Cards3. Exit

Date Lecture/ Activity/ Lab Page 10/15 Cell Transport and Homeostasis Term Notes 65-66 10/16 Osmosis in Cells Lab 67-6810/18 Observing Osmosis in Elodea 69-7010/21 Cell Analogies Poster 71-7210/24 Cell Transport Cards 73-7410/25 Experimental Design 75-76

Table of Contents

PHOTOSYNTHESISPHOTOSYNTHESIS

It’s all about ENERGY!

• Energy flow through the ecosystem allows life to exist.

• All organisms require energy to live.• Some organisms produce their own food as

energy, such as autotrophs (producers)– Some convert sunlight into food by the process of

photosynthesis. Ex: plants, algae– Some convert chemicals into food by the process of

chemosynthesis. Ex: sulfur bacteria in deep sea.

• Energy is stored in food as chemical energy.

ATP is a bundle of energy!

• ATP= adenosine triphosphate

• ADP= adenosine diphosphate• ADP and single phosphate groups are available in cells to store up

extra energy.• When energy is released from food, it can be stored in the bonds

that bind the phosphate group to the ADP molecule.• That stored energy is later released when the bond breaks between

the ADP and P.

• ADP + P ATP (stored energy)

• ATP ADP + P (energy released)

Energy is stored in ATP

Stored energy (created by cellular

respiration)

Released energy (used for cellular activities)

What is the ultimate source of ALL energy?

How does energy get from the sun into the foods we eat?

energy

energy

The sun sends downs little packets of light energy called: PHOTONS

Photons group together in waves, each “wave” having a different length and color

Photons

Wavelengths

WWhhyy ddoo wwe e sseeee ccoolloorrss??????

Plants appear GREEN because they reflect this color

of light (and they absorb red, orange,

and violet)

Compounds that absorb and reflect wavelengths of light are called pigments.

What colors are being absorbed and what colors are being reflected?

Photos courtesy of flowerpictures.net and picturesof.net

What do we call the compounds that absorb and reflect wavelengths of light?

pigments

Which pigment reflects the green wavelengths thereby making plants appear green?

chlorophyll

Where would we find chlorophyll? chloroplasts

WWhhyy ddoo wwe e sseeee ccoolloorrss??????

Chloroplast StructureDisks called THYLAKOIDS contain the pigment CHLOROPHYLL.

FYI: A stack of thylakoids is called a

grana.

The liquid portion of a chloroplast is the STROMA.

Where do we find chloroplasts?

stomata

Chloroplasts containing chlorophyll

(Chloroplasts are found in cells of leaves and other green parts of plants.)

Review1. What is the ultimate source of all

energy?

2. In what form does light energy come to the earth?

3. What compounds absorb wavelengths?

4. How do we see colors?

5. Where in a leaf do we find pigments?

What process captures the light energy and uses it to

make food?

Photosynthesis• What is photosynthesis?

• Photosynthesis is the process by which: Plants (producers)

water

carbon dioxide

oxygen

glucose

TAKE IN AND USING MAKE

PLANTS(producers)

light

chlorophyll

Photosynthesis

6CO2 + 6H2O 6O2 + C6H12O6

light

chlorophyll

Where does photosynthesis

occur?

• Inside of chloroplasts which are located in cells of the green parts of plants

Photosynthesis– Light reactions– Dark reactions/ light independent reactions (aka Calvin cycle)

Light Reaction Dark ReactionLIGHT REACTION Dark Reaction

grana(chlorophyll)

Photosynthesis• Light Reactions (the “photo” part of photosynthesis)

– Occur in the grana (thylakoids)– Can only occur in the presence of light– Convert solar energy to chemical energy

light

Light ReactionsStep 1- Absorption of Light Energy

• Pigments (light absorbing substances) in autotrophs collect sunlight that is used in photosynthesis.

• Chlorophyll is stored in chloroplasts in cells.

• Clusters of chlorophyll are embedded in the membranes of disk-shaped structures called thylakoids. This is where photosynthesis occurs.

Light Reactions Step 1- Absorption of Light Energy

• Light strikes the thylakoid, causing electrons to be excited with extra energy.

• The excited electrons then leave chlorophyll to jump to other molecules in the thylakoid.

• The electrons that left the chlorophyll must be replaced, so they are borrowed from water molecules.

• Water molecules are split, sending the electrons from the H to the chlorophyll, and giving off oxygen gas. H+ atoms are also left over.

• Summation: sunlight in, energy (excited electrons) gained, oxygen gas released.

Light Reactions

ENERGY

(1) light energy reacts with the chlorophyll

(3) O2 is given off while H is kept for the dark reactions

(2) water is split by the light energy H2O

O

H2

Light ReactionsStep 2- Conversion of Light Energy

• The excited electrons leave the chlorophyll and are passed to other molecules down a series of molecules in the thylakoid membrane by a process called the ELECTRON TRANSPORT CHAIN.

• Some of the energy of the electrons is used to pump H+ atoms through the thylakoid, which is then used to make ATP, stored energy.

• Another ELECTRON TRANSPORT CHAIN is used to make NADPH, which is also a form of stored energy that is used to make bonds in Step 3.

Light Reaction Dark ReactionLight Reaction DARK REACTION

stroma(liquid)

Photosynthesis• Dark Reactions (aka Calvin Cycle)- the “synthesis” part of photosynthesis

– Occur in the stroma

– Can occur in the presence of light or dark

Dark ReactionsStep 3- Storage of Energy

• Step 3 is called the “dark reactions” , or “light-independent reactions” because sunlight is not needed.

• In Step 3, the ATP and NADPH made from the earlier stages are used to make organic compounds, or the “food” (glucose)

Dark ReactionsStep 3- Storage of Energy

• The CALVIN CYCLE takes place in Step 3.• CALVIN CYCLE summary:

– CO2 is added to 5-carbon compound. The process of transferring carbon dioxide to organic compounds is called CARBON DIOXIDE FIXATION.

– The new 6-carbon compound splits into 2 3-carbon compounds.

– Phosphate groups from ATP and electrons from NADPH are added to the 3-carbon compounds to make them 3-carbon sugars.

– One of the sugars is then made into carbohydrates, and the other is recycled to make the Calvin Cycle run again.

Overview of the Calvin Cycle

• CO2 enters the cycle and leaves as sugar.

• The cycle spends the energy of ATP and NADPH to make the sugar.

Dark Reactions (light independent)

• AKA: CALVIN CYCLE

C6H12O6

(1) CO2 enters the chloroplast

(2) the H left from the light reactions combine with the incoming CO2

H + CO2

(3) Glucose is the eventual product

Photosynthesis– Light reactions– Dark reactions/ light independent reactions (aka Calvin cycle)

Factors affecting photosynthesis

• Intensity of light– high light, high rate

• Carbon dioxide concentration– high CO2, high rate

• Temperature– A certain range works best, too hot or

too cold affects the work of enzymes

Who was Calvin anyway?• A member of the faculty at

UC Berkeley since 1937, Melvin Calvin received the 1961 Nobel prize in chemistry for identifying the path of carbon in photosynthesis.

• The cycle of reactions in the dark phase of photosynthesis was named after him for his work in identifying the processes taking place.

Photosynthesis Review

• Light reactions: H2O split into H2 + O

• Dark reactions: H + CO2 = C6H12O6

H2O Light Reaction Dark ReactionC

O 2

C6H12O6

O 2

chlorophyll

Photosynthesis Review• What goes in? (the reactants)

• What comes out? (the products)

H2O Light Reaction Dark Reaction

CO 2

C6H12O6

O 2

chlorophyll

6CO2 + 6H2O 6O2 + C6H12O6

light

chlorophyll

Photosynthesis Formula

• How would this be written as a chemical equation?• What goes in? (the reactants)• What comes out? (the products)

H2O Light Reaction Dark ReactionC

O 2C6H12O6

O 2

chlorophyll

6 H2O 6 CO2 C6H12O6 6 O2