1. Photosynthesis
Energy & Life

2. Autotrophs Autotrophs include organisms that make their own food
Autotrophs can use the sun’s energy directly
Euglena

3. Heterotrophs
Heterotrophs are organisms that can NOT make their own food
Heterotrophs can NOT directly use the sun’s energy

4. ATP – Cellular Energy Adenosine Triphosphate
Contains two, high-energy phosphate bonds
Also contains the nitrogen base adenine & a ribose sugar

5. One phosphate bond has been removed
ADP
Adenosine Diphosphate
ATP releases energy, a free phosphate, & ADP when cells take energy from ATP
One phosphate bond has been removed

6. Sugar in ADP & ATP
Called ribose
Pentose sugar
Also found in RNA

7. Importance of ATP
Principal Compound Used To Store Energy In Living Organisms

8. Releasing Energy From ATP
ATP is constantly being used and remade by cells
ATP provides all of the energy for cell activities
The high energy phosphate bonds can be BROKEN to release energy
The process of releasing ATP’s energy & reforming the molecule is called phosphorylation

9. Releasing Energy From ATP
Adding A Phosphate Group To ADP stores Energy in ATP
Removing A Phosphate Group From ATP Releases Energy & forms ADP
Loose
Gain

10. Cells Using Biochemical Energy
Cells Use ATP For:
Active transport
Movement
Photosynthesis
Protein Synthesis
Cellular respiration
All other cellular reactions

11. More on ATP Cells Have Enough ATP To Last For A Few Seconds
ATP must constantly be made
ATP Transfers Energy Very Well
ATP Is NOT Good At Energy Storage

12. Glucose Glucose is a monosaccharide C6H12O6
One Molecule of glucose Stores 90 Times More Chemical Energy Than One Molecule of ATP

13. Photosynthesis
Involves the Use Of light Energy to convert Water (H20) and Carbon Dioxide (CO2) into Oxygen (O2) and High Energy Carbohydrates (sugars, e.g. Glucose) & Starches

14. The Photosynthesis Equation

15. Pigments
In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments
Chlorophyll is the primary light-absorbing pigment in autotrophs
Chlorophyll is found inside chloroplasts

16. Light and Pigments Photon = Light Energy Unit
Energy From The Sun Enters Earth’s Biosphere As Photons
Photon = Light Energy Unit
Light Contains A Mixture Of Wavelengths
Different Wavelengths Have Different Colors

17. Light & Pigments
Different pigments absorb different wavelengths of light
Photons of light “excite” electrons in the plant’s pigments
Excited electrons carry the absorbed energy
Excited electrons move to HIGHER energy levels

18. Magnesium atom at the center of chlorophyll
There are 2 main types of chlorophyll molecules:
Chlorophyll a
Chlorophyll b
Magnesium atom at the center of chlorophyll

19. Chlorophyll a Found in all plants, algae, & cyanobacteria
Makes photosynthesis possible
Participates directly in the Light Reactions
Can accept energy from chlorophyll b

20. Chlorophyll b Chlorophyll b is an accessory pigment
Chlorophyll b acts indirectly in photosynthesis by transferring the light it absorbs to chlorophyll a
Like chlorophyll a, it absorbs red & blue light and REFLECTS GREEN

21. Inside A Chloroplast

22. Structure of the Chloroplast
Double membrane organelle
Outer membrane smooth
Inner membrane forms stacks of connected sacs called thylakoids
Thylakoid stack is called the granun (grana-plural)
Gel-like material around grana called stroma

23. Function of the Stroma Light Independent reactions occur here
ATP used to make carbohydrates like glucose
Location of the Calvin Cycle

25. Thylakoid membranes Light Dependent reactions occur here
Photosystems are made up of clusters of chlorophyll molecules
Photosystems are embedded in the thylakoid membranes
The two photosystems are:
Photosytem I
Photosystem II

26. Photosynthesis Overview

27. Energy Carriers NADP+ = Reduced Form
Nicotinamide Adenine Dinucleotide Phosphate (NADP+)
NADP+ = Reduced Form
Picks Up 2 high-energy electrons and H+ from the Light Reaction to form NADPH
NADPH carries energy to be passed on to another molecule

28. Light Dependent Reactions
Occurs across the thylakoid membranes
Uses light energy
Produce Oxygen from water
Convert ADP to ATP
Also convert NADP+ into the energy carrier NADPH

29. Light Dependent Reaction

30. Light Dependent Reaction

31. Photosystem I Discovered First
Active in the final stage of the Light Dependent Reaction
Made of 300 molecules of Chlorophyll
Almost completely chlorophyll a

32. Photosystem II Discovered Second
Active in the beginning stage Of the Light Dependent Reaction
Contains about equal amounts of chlorophyll a and chlorophyll b

33. Photosynthesis Begins
Photosystem II absorbs light energy
Electrons are energized and passed to the Electron Transport Chain
Lost electrons are replaced from the splitting of water into 2H+, free electrons, and Oxygen
2H+ pumped across thylakoid membrane

34. Photosystem I
High-energy electrons are moved to Photosystem I through the Electron Transport Chain
Energy is used to transport H+ from stroma to inner thylakoid membrane
NADP+ converted to NADPH when it picks up 2 electrons & H+

35. Phosphorylation Enzyme in thylakoid membrane called ATP Synthase
As H+ ions passed through thylakoid membrane, enzyme binds them to ADP
Forms ATP for cellular

37. Light Reaction Summary
Reactants:
H2O
Light Energy
Energy Products:
ATP
NADPH

38. Light Independent Reaction
ATP & NADPH from light reactions used as energy
Atmospheric C02 is used to make sugars like glucose and fructose
Six-carbon Sugars made during the Calvin Cycle
Occurs in the stroma

39. The Calvin Cycle

40. The Calvin Cycle
Two turns of the Calvin Cycle are required to make one molecule of glucose
3-CO2 molecules enter the cycle to form several intermediate compounds (PGA)
A 3-carbon molecule called Ribulose Biphosphate (RuBP) is used to regenerate the Calvin cycle

42. Factors Affecting the Rate of Photosynthesis
Amount of available water
Temperature
Amount of available light energy