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Narcissus Flowers

1. Photosynthesis

4. References

2. Photosynthesis in Inspiration

3. Using Inspiration

Photosynthesis

• Photosynthesis transforms solar light energy trapped by chloroplasts into:

-chemical bond energy of carbohydrates.

Autotroph vs. Heterotroph• Organisms acquire organic molecules through either:

1. Autotrophic Nutrition(Auto = self; troph = feed): •Producers•Photoautotrophs and chemoautotrophs•ex: plants, algae, some prokaryotes

2. Heterotrophic Nutrition (Heteros = other; troph = nutrition): •Consumers•ex: animals that eat plants or other animals, decomposers.

Chloroplasts

• The site where photosynthesis occurs

• Located in leaves• Chlorophyll is located in

chloroplasts• Chlorophyll is the green

pigment that gives photosynthetic organisms its color.

Chloroplast

Chloroplasts

Grana (singular granum)

Thylakoid Stroma

Outer Membrane

Inner Membrane

Chloroplasts

•Chlorophyll is found in the thylakoid.

•Converts light energy to chemical energy (PSI & PSII).

Thylakoid Grana (singular granum)

Stroma

Outer Membrane

Inner Membrane

Chloroplasts

Thylakoid Grana (singular granum)

Grana is stacks of thylakoids in the chloroplast

Stroma

Outer Membrane

Inner Membrane

Chloroplasts

Thylakoid Grana (singular granum)

•Stroma is the fluid outside the thylakoids.

•Uses chemical energy to convert carbon dioxide to sugar (Calvin Cycle)

Stroma

Outer Membrane

Inner Membrane

Chloroplasts

Thylakoid Grana (singular granum)

Stroma

Chloroplasts are surrounded by two membranes

Outer Membrane

Inner Membrane

Chloroplasts

Thylakoid

•Chlorophyll is found in the thylakoid.

•Converts light energy to chemical energy (PSI & PSII).

Grana (singular granum)

Grana is stacks of thylakoids in the chloroplast

Stroma

•Stroma is the fluid outside the thylakoids.

•Uses chemical energy to convert carbon dioxide to sugar (Calvin Cycle)

Outer Membrane

Inner Membrane

Chloroplasts are surrounded by two membranes

Photosynthesis Pathway

Overall equation:

6CO2 + 6H2O + light energy C6H12O6 + 6O2

Splitting of Water:

O2 released by plants comes from the splitting of water, not from CO2.

Plants split water as a source of hydrogen and release oxygen as a by-product.

Light Reactions OverviewLight (Dependent) Reactions = Convert light energy to chemical bond energy in ATP and NADPH (energy capturing rxns.)

1. Occurs in the thylakoid membrane.

Two Types:

1. Cyclic (generates ATP and uses PS I)

2. Noncyclic (generates ATP and NADPH and uses PSI and PSII).

Light Independent Reactions OverviewLight Independent Reactions = Calvin cycle which makes sugars (synthesis rxns).

1. Occurs in the stroma of the chloroplast.

2. Calvin Cycle (3 Parts)

1.Incorporates atmospheric CO2 into existing organic molecules (carbon fixation)

2. CO2 Reduction

3. Regeneration of RUBP

Solar Energy

•Solar radiation is described in terms of its energy content and its wavelength.

•The electromagnetic spectrum is the range of types of solar radiation based on wavelength.

•Short wavelength = higher energy content and

•Long wavelength = lower energy content.

Solar Energy•A graph of wavelength versus rate of photosynthesis is an action spectrum.

•Shows effectiveness of different wavelengths of visible light for driving photosynthesis.

•Accessory Pigments expand the range of wavelengths available for photosynthesis.

- chlorophyll b: yellow-green pigment

-chlorophyll a: slightly diff. absorption spectrum

-carotenoids: yellow-orange hydrocarbons

Photosystems• Pigments are assembled into

photosystems located within the thylakoid membrane.

• A photosystem absorbs solar energy and generates high energy electrons.

• Each photosystem is composed of:

-Antenna complex

-Reaction-Center chlorophyll

-Primary electron acceptor

• There are 2 types of photosystems:

1. Photosystem I P700

2. Photosystem II P680

Cyclic Electron Pathway

•Simplest pathway - generates ATP and no NADPH or Oxygen. It uses only PS I.•It is cyclic because excited electrons that leave from the chlorophyll a at the reaction center return to the reaction center. •Cyclic supplements the ATP supply required for the Calvin cycle and other metabolic pathways.•Some photosynthetic bacteria use cyclic only-may have evolved early.•May be utilized only when CO2 is in limited supply.

Cyclic Electron Cyclic Electron PathwayPathway

•Photons are absorbed by PS I.•Reaction Center releases excited electrons to the electron acceptor.•Electrons are passed to Ferredoxin.

•Electrons travel down Electron transport System (ETS). -as they move down ETS they pass from higher to lower

energy level -energy released is stored in form of H+ gradient. -When H+ ions flow down their electrochemical gradient

through ATP synthase complesxes, ATP is produced. (Chemiosmosis)

NonCyclic Electron PathwayNonCyclic Electron Pathway

•Both PS I and PS II are used.•NADPH and ATP are produced.•Occurs in the thylakoid membrane.•Produces Oxygen.•Electrons move from water through PSI/PSII and then on to NADP+ •PS II takes replacement electrons

from water, which splits, releasing O2 and H+ ions - Photolysis.

NonCyclic Electron PathwayNonCyclic Electron Pathway

•Again in PSI, excited electrons are passed to an electron acceptor and then to ferredoxin.•Ferredoxin passes the electrons to NADP+ to produce NADPH

•PS II absorbs light energy and boosts electrons.•Electrons are passed to the primary electron acceptor and then to the ETS.•Electrons lose potential energy (and produce ATP) as they move down the ETS and arrive at the PS I.•Light excites electrons in PSI- these excited electrons do not return to the rxn center but are stored in NADPH.

ChemiosmosisChemiosmosis•Chemiosmosis is a coupled reaction.•The thylakoid space acts as a reservoir for H+ ions; each time water is split, two H+ remain. •Elecrons move carrier to carrier, giving up energy to pump H+ from stroma into thylakoid space.

•Flow of H+ from high to low concentration across thylakoid membrane provides energy to produce ATP from ADP using the ATP synthase enzyme.•In Photosynthesis this process is called photophosphorylation.•ATP is produced on the outside of the thylakoid, depositing it in the stroma for use in the Calvin Cycle.

Light Independent Reactions Light Independent Reactions (Dark Reactions)(Dark Reactions)

• Light is not directly required, CO2 is required.

• The Calvin Cycle uses ATP and NADPH from the light rxns to convert CO2 to CH2O. (CO2 is reduced)

• CO2 reduction occurs in the stroma of a chloroplast.

• Calvin Cycle has 3 Parts.

Calvin Cycle: Calvin Cycle: Part 1Part 1

Carbon Carbon FixationFixation

• CO2 fixation is the attachment of CO2 to an organic compound.

• RuBP is the 5 carbon molecule that combines with CO2.

• Enzyme RuBP carboxylase (rubisco) speeds reaction.

• The product of this reaction is an unstable 6 carbon intermediate molecule

Calvin Cycle: Calvin Cycle: Part 2Part 2

Reduction of Reduction of COCO22

• 6 carbon intermediate immediately breaks down into 2 PGA molecules (3-phosphoglycerate C3).

• Each of two PGA molecules undergoes reduction to PGAL in two steps.

• Light dependent reactions provide NADPH (Electrons) and ATP (energy) to reduce PGA to PGAL (G3P).

• It takes 2 PGAL to make 1 Glucose, 6 turns of the Calvin Cycle.

Calvin Cycle: Part Calvin Cycle: Part 33

Regeneration of Regeneration of RuBPRuBP

• Every 3 turns of the Calvin Cycle, 6 PGAL are produced. • 5 PGAL are used to regenerate 3 RuBP and 1 is used to

build carbohydrate.• It takes 2 PGAL to build 1 Glucose.• PGAL is the raw material that can be used to synthesisze

other carbohydrates as well• To make this glucose 18 ATP and 12 NADPH are used.

Modes of Photosynthesis

• The Calvin Cycle, as discussed here, is also called C3

photosynthesis. • This is because the 1st molecule created (PGA) is a 3 carbon

molecule.

Modes of Photosynthesis

PhotorespirationPhotorespiration• A metabolic pathway that consumes

oxygen, evolves CO2, produces no ATP and decreases photosynthesis.

•Occurs because active site of rubisco can accept O2 as well as CO2

•When O2 concentration in a leaf’s air spaces is higher than CO2, rubisco accepts O2 and tranfers it to RuBP.•Whether photorespiration is beneficial to plants is not known. •If photorespiration could be reduced in agricultural plants, crop yields and food supplies would increase.•Photorespiration is fostered by hot, dry, bright days when plants don’t open stomata to reduce water loss.

Modes of Modes of PhotosynthesisPhotosynthesis

• Sometimes PGA (a 3 carbon molecule) is not the first molecule created.

• C4 plants fix CO2 by forming a C4

molecule prior to the involvement of the Calvin cycle.

• CAM plants fix CO2 by forming a C4 molecule at night when stomates can open without loss of water.

**These alternate forms are adaptations to minimize photorespiration.

• In C3 plants, mesophyll cells contain chloroplasts arranged in parallel layers.

• In C4 plants, bundle sheath cells as well as mesophyll cells contain chloroplasts.

• In C4 leaves, mesophyll cells are arranged concentrically around the bundle sheath cells.

CC4 4

PhotosynthesisPhotosynthesis

• C4 plants use the enzyme PEP carboxylase (PEPcase) to fix CO2 to PEP; end product is oxaloacetate (OAA-a 4 carbon molecule).

• OAA is then converted to malate and the malate is shuttled to bundle sheath cells. Here malate is converted to pyruvate and CO2.

•Pyruvate is then shuttled a back to meophyll cells where one 1 ATP is required to convert the pyruvate back into PEP. •The overall effect is to move CO2 from mesophyll cells to bundle sheath cells.

CC4 4 PhotosynthesisPhotosynthesis• The purpose of moving CO2 to

bundle sheath cells is to increase efficiency of photosynthesis.

• Very little oxygen reaches bundle sheath cells so when malate delivers CO2 to them rubisco begins Calvin cycle.

• Because little oxygen is present here, CO2 can be fixed without competition from O2.

• Little photorespiration takes place and photosynthesis is more efficient.

•In hot, dry climates, net photosynthestic rate of C4

plants is 2-3 times that of C3 plants.

Modes of Photosynthesis

CAM PlantsCAM Plants

• CAM = crassulacean acid metabolism.• Exists in succulent plants adapted to very arid conditions.

These plants open their stomata primarily at night and close them during the day (opposite of most plants)

• Conserves water during the day but prevents CO2 from entering the leaves.

• When stomata are open at night, CO2 is incorporated into a variety of organic acids.

CAM CAM PlantsPlants

• During the day, light reactions supply ATP and NADPH for the Calvin Cycle.

• At this time, CO2 is released from the organic acids and used to make sugars.

• Organic acids are stored in vacuoles until morning when the stomata close.

A Review of PhotosynthesisA Review of Photosynthesis• On a global scale, photosynthesis makes

about 160 billion metric tons of carbohydrate per year.

• No other chemical process on Earth is more productive or is as important to life.

• Photosynthesis transforms light energy to chemical bond energy in sugar molecules

A Review of PhotosynthesisA Review of Photosynthesis

• Light reactions capture solar energy and use it to produce ATP and transfer electrons from water to NADP to form NADPH.

• The Calvin cycle uses ATP and NADPH to fix CO2 and produce sugar.

• Photorespiration can reduce photosynthetic yield in hot dry climates.

A Review of PhotosynthesisA Review of Photosynthesis

• Alternate methods of carbon fixation minimize photorespiration.

• C4 plants spatially separate carbon fixation from the Calvin Cycle

• CAM plants temporarily separate carbon fixaton from the Calvin Cycle.

• Regardless of whether the plant uses C3, C4 or CAM pathway, all plants use the Calvin Cycle to produce sugar from CO2.

Using InspirationOpening Inspiration:Opening Inspiration:

1. Go to START, then to PROGRAMS, then to Inspiration.

2. In Inspiration go to File menu.

3. Choose Save.

4. Save file as: “your last name_photosynthesis”

Using InspirationMaking your graphic organizer with Inspiration.Making your graphic organizer with Inspiration.

5. Click on the symbol with “Main Idea.”

6. Type in Photosynthesis. This is your main idea.

Using Inspiration7. Now click on Rapid Fire located at the top menu bar.

Using Inspiration8. Type a subtopic of Photosynthesis and then hit return. This will give

you another circle.

9. Continue to type in different subtopics you would like to address.

10. Click on one of your subtopics and click on the Rapid Fire button. This will allow you to create another link off that subtopic.

Using InspirationAdding pictures to your graphic organizer from Inspiration Library.Adding pictures to your graphic organizer from Inspiration Library.

11. Highlight the circle you would like to change.

12. Go over to the menu bar on the left with different symbols.

13. Click on the arrow at top that will show different types of symbols.

14. Chose one and click on it. This will change your symbol.

Using InspirationAdding pictures to your graphic Adding pictures to your graphic organizer from the Internet.organizer from the Internet.

15. Open up Internet Explorer and go to Google Images.

16.Type in key word and click search.

17. Find Image and save to desktop.

18. Don’t forget to name Image.

19. Click back on Inspriation.

SAVE YOUR WORK WHEN FINISHED!

20. Go to Edit.

21. Scroll down to Insert Graphic.

22. New window will come up and click on desktop.

23. Find image and click return.

PHOTOSYNTHESIS

General Equation

Light Reactions

Light Independent Reactions

6 CO2 + 6 H2O + Light

Energy = C6H12O6

+ 6O2

Occurs in the thylakoid membranes

Calvin Cycle

Light is not required

Photosystem 1

Photosystem 2

Occurs in the stroma

of the chloroplast

1. http://nakahara.ac/flower/flower-large/narcissus.jpg

2. http://sunflower.bio.indiana.edu/~rhangart/plantmotion/ flowers/flower.html

3. http://www.free-clipart.net/main.html

4. www.rosswarner.com/2988.html

5. www.madsci.org/posts/ archives/1065583527.Zo.1 .jpg

6. http://35.9.122.184/images/10-Photosynthesis/10-02-Chloroplast-NL.gif

7. http://www.ualr.edu/~botany/chloroplast.jpg

8. http://www.photo.net/philg/digiphotos/200108-nikon995-macro/orchid-straight.half.jpg

9. http://35.9.122.184/images/10-Photosynthesis/HTML/ source /37.html&h=600&w=528&sz=40&tbnid\

10. http://www.msu.edu/course/lbs/145/smith/s02/graphics/ campbell_10.16.gif

11. bio.winona.msus.edu/ berg/241f99/Labs/Lab9-PS.htm

12. Kelsey Prock

13. Tina Doss