Photosynthesis: The Calvin Cycle

Life from CO2

The Calvin CycleWhoops! Wrong Calvin…1950s | 1961

Remember what it means to be a plant… Need to produce all organic molecules

necessary for growth carbohydrates, lipids, proteins, nucleic acids

Need to store chemical energy (ATP) produced from light reactions in a more stable form that can be moved around plant saved for a rainy day

+ water + energy glucose + oxygencarbondioxide

6CO2 6H2O C6H12O6 6O2light

energy + ++

Light reactions What is generated in these

reactions?ATP

NADPH

O2 (waste)

energy

reducing power

Now we can build stuff !!

photosynthesis

ATP

How is that helpful? Want to make C6H12O6

synthesis How? From what?

What raw materials are available?

CO2

C6H12O6

NADPH

NADPreduces CO2carbon fixation

NADP

From Light reactions to Calvin cycle

stroma

thylakoid

ATP

starch,sucrose,cellulose& more

1C CO2

Calvin cycle

5CRuBP

3C

RuBisCo

1. Carbon fixation

2. Reduction

3. Regenerationof RuBP

ribulose bisphosphateribulose

bisphosphate carboxylase

6 NADP

6 NADPH 6 ADP

6 ATP

3 ADP

3 ATP

usedto make

glucose

3C

3CG3Pglyceraldehyde-3-P

C C C C C

C C C C C

C C C C C

6C

C C C C C C

C C C C C C

C C C C C C

C C C

C C C

C C C

C C C

C C C

C C C

PGAphosphoglycerate

C C C

C C C

C C C

C C C

C C C

C C CC C C

CC

C

C C C= =

|H

|H

|H

|H

|H

|H

C C C– –

5C

glycolysis

glucoseC-C-C-C-C-C

fructose-1,6bPP-C-C-C-C-C-C-P

DHAPP-C-C-C

G3PC-C-C-P

pyruvateC-C-C

ATP2

ADP2

ATP4

ADP4

NAD+22

Remember G3P?

glyceraldehyde3-phosphate

Photosynthesis

To G3P and Beyond! Glyceraldehyde-3-P

end product of Calvin cycle energy rich 3 carbon sugar “C3 photosynthesis”

G3P is an important intermediate G3P glucose carbohydrates

lipids phospholipids, fats, waxes

amino acids proteins

nucleic acids DNA, RNA

To G3Pand beyond!

RuBisCo Enzyme which fixes carbon from air

ribulose bisphosphate carboxylase the most important enzyme in the world!

it makes organic molecules from CO2!

definitely the most abundant enzyme

I’m green with envy!

It’s not easy being green!

Light Reactions

O2

H2O

Energy BuildingReactions

ATP

produces ATP produces NADPH releases O2 as a

waste product

sunlight

H2O ATP O2light

energy ++ + NADPH

NADPH

Calvin Cycle

sugars

CO2

SugarBuilding

Reactions

ADP

builds sugars uses ATP &

NADPH recycles ADP

& NADP back to make

more ATP & NADPHATP

NADPH

NADP

CO2 C6H12O6 ++ + NADPATP + NADPH ADP

Putting it all together

CO2 H2O C6H12O6 O2light

energy + ++

SugarBuilding

Reactions

Energy Building

Reactions

Plants make both:energy

ATP & NADPHsugars

sunlight

O2

H2O

sugars

CO2

ADP

ATP

NADPH

NADP

H2O

Energy cycle

Photosynthesis

Cellular Respiration

sun

glucose O2CO2

plants

animals, plants

ATP

CO2 H2O C6H12O6 O2light

energy + ++

CO2 H2OC6H12O6 O2ATP

energy+ ++

Summary of photosynthesis

Where did the CO2 come from? Where did the CO2 go? Where did the H2O come from? Where did the H2O go? Where did the energy come from? What’s the energy used for? What will the C6H12O6 be used for? Where did the O2 come from? Where will the O2 go? What else is involved…not listed in this equation?

6CO2 6H2O C6H12O6 6O2light

energy + ++

Supporting a biosphere

On global scale, photosynthesis is the most important process for the continuation of life on Earth each year photosynthesis…

captures 121 billion tons of CO2

synthesizes 160 billion tons of carbohydrate heterotrophs are dependent on plants as

food source for fuel & raw materials

The poetic perspective… All the solid material of every plant

was built by sunlight out of thin air All the solid material of every animal

was built from plant material

Then all the plants, cats, dogs, elephants & people …

are really particles of air woven together by strands of sunlight!

sunair

If plants can do it…You can learn it!

Ask Questions!!