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Photosynthesis. PHOTOSYNTHESIS 3 Photosynthesis Carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce.

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Presentation on theme: "Photosynthesis. PHOTOSYNTHESIS 3 Photosynthesis Carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce."— Presentation transcript:

1 Photosynthesis

2 PHOTOSYNTHESIS

3 3 Photosynthesis Carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce organic macromolecules (glucose).Carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce organic macromolecules (glucose). 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 glucose SUN photons

4 4 Question: Where does photosynthesis take place?

5 5 Plants Autotrophs – produce their own food (glucose)Autotrophs – produce their own food (glucose) Process called photosynthesisProcess called photosynthesis Mainly occurs in the leaves:Mainly occurs in the leaves: a.stoma - pores b.mesophyll cells Stoma Mesophyll Cell Chloroplast

6 6 Stomata (stoma) Pores in a plant’s cuticle through which water vapor and gases (CO 2 & O 2 ) are exchanged between the plant and the atmosphere. Guard Cell Carbon Dioxide (CO 2 ) Oxygen (O 2 ) Found on the underside of leaves Stoma

7 7 Mesophyll Cell of Leaf Cell Wall Nucleus Chloroplast Central Vacuole Photosynthesis occurs in these cells!

8 8 Chloroplast Organellephotosynthesis Organelle where photosynthesis takes place. Granum Thylakoid Stroma Outer Membrane Inner Membrane Thylakoid stacks are connected together

9 9 Thylakoid Thylakoid Membrane Thylakoid Space Granum Grana make up the inner membrane

10 Light Dependent Reactions 10

11 11 Question: Why are plants green?

12 12 Chlorophyll Molecules Located in the thylakoid membranes]Located in the thylakoid membranes] Chlorophyll pigments harvest energy (photons) by absorbing certainChlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue-420 nm and red- 660 nm are most important) wavelengths (blue-420 nm and red- 660 nm are most important) Plants are green because the green wavelength is reflected, not absorbedPlants are green because the green wavelength is reflected, not absorbed.

13 Amazing Chloroplast 13

14 14 Wavelength of Light (nm) 400500600700 Short waveLong wave (more energy)(less energy)

15 15 Absorption of Light by Chlorophyll wavelength Absorption violet blue green yellow orange red Chlorophyll absorbs blue-violet & red light best

16 16 Question: During the fall, what causes the leaves to change colors?

17 17 Fall Colors In addition to the chlorophyll pigments, there are other pigments presentIn addition to the chlorophyll pigments, there are other pigments present During the fall, the green chlorophyll pigments are greatly reduced revealing the other pigmentsDuring the fall, the green chlorophyll pigments are greatly reduced revealing the other pigments Carotenoids are pigments that are either red, orange, or yellowCarotenoids are pigments that are either red, orange, or yellow

18 18 Question: What do cells use for energy?

19 19

20 How do cells obtain energy? 20

21 21 Energy for Life on Earth Sunlight is the ULTIMATE energy for all life on Earth Plants store energy in the chemical bonds of sugars Chemical energy is released as ATP during cellular respiration

22 22 Structure of ATP ATP stands for adenosine triphosphate It is composed of the nitrogen base ADENINE, the pentose (5C) sugar RIBOSE, and three PHOSPHATE groups The LAST phosphate group is bonded with a HIGH ENERGY chemical bond This bond can be BROKEN to release ENERGY for CELLS to use

23 23 Removing a Phosphate from ATP Breaking the LAST PHOSPHATE bond from ATP, will --- –Release ENERGY for cells to use –Form ADP –Produce a FREE PHOSPHATE GROUP

24 24 High Energy Phosphate Bond

25 25 FREE PHOSPHATE can be re-attached to ADP reforming ATP Process called Phosphorylation

26 26 Parts of Photosynthesis

27 Types of Photosynthesis 27

28 28 Two Parts of Photosynthesis Two reactions make up photosynthesis: 1.Light Reaction or Light Dependent Reaction - Produces energy from solar power (photons) in the form of ATP and NADPH. SUN

29 29 Two Parts of Photosynthesis 2. Calvin Cycle or Light Independent Reaction Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).

30 30 Light Reaction (Electron Flow) Occurs in the Thylakoid membranesOccurs in the Thylakoid membranes

31 31 Calvin Cycle Carbon Fixation (light independent reaction)Carbon Fixation (light independent reaction) C 3 plants (80% of plants on earth)C 3 plants (80% of plants on earth) Occurs in the stroma Occurs in the stroma Uses ATP and NADPH from light reaction as energyUses ATP and NADPH from light reaction as energy Uses CO 2Uses CO 2 To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH.To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH.

32 32 Chloroplast Granum Thylakoid STROMA– where Calvin Cycle occurs Outer Membrane Inner Membrane

33 33 Calvin Cycle Remember: C 3 = Calvin Cycle C3C3 Glucose

34 34 Photorespiration Occurs on hot, dry, bright daysOccurs on hot, dry, bright days Stomates close Stomates close Fixation of O 2 instead of CO 2Fixation of O 2 instead of CO 2 Produces 2-C molecules instead of 3-C sugar moleculesProduces 2-C molecules instead of 3-C sugar molecules Produces no sugar molecules or no ATPProduces no sugar molecules or no ATP

35 35 Photorespiration Because of photorespiration, plants have special adaptations to limit the effect of photorespiration: 1.C 4 plants 2.CAM plants

36 36 C 4 Plants Hot, moist environmentsHot, moist environments 15% of plants (grasses, corn, sugarcane)15% of plants (grasses, corn, sugarcane)

37 37 CAM Plants Hot, dry environmentsHot, dry environments 5% of plants (cactus and ice plants)5% of plants (cactus and ice plants) Stomates closed during dayStomates closed during day Stomates open during the nightStomates open during the night Light reaction - occurs during the dayLight reaction - occurs during the day Calvin Cycle - occurs when CO 2 is presentCalvin Cycle - occurs when CO 2 is present

38 38 Question: Why do CAM plants close their stomata during the day?

39 Cam plants close their stomata in the hottest part of the day to conserve water

40 What is the Difference ? Journal in your notebooks using a Venn diagram to discuss your comparisons between C3 and C4 Plants. 40


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