1. REACTIONS OF PHOTOSYNTHESIS 8-3
REACTIONS OF PHOTOSYNTHESIS 8-3

2. Remember from Cell unit
Enzymes for PHOTOSYNTHESIS are in the ________________
CHLOROPLASTS

3. PHOTOSYNTHESIS HAPPENS IN CHLOROPLASTS
THYLAKOIDS
= sac-like
photosynthetic = stack of thylakoids
membranes
inside chloroplast
GRANUM (pl. grana)
Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

4. SPACES THYLAKOID SPACE STROMA cytoplasm
Gel-filled space inside chloroplast surrounding
thylakoid sac
Gel-filled space
Inside the
thylakoid
sac
cytoplasm
Gel-filled space OUTSIDE chloroplast but inside the cell membrane

5. Photosynthesis video click on Light-Dependent
See a video clip about the LIGHT-DEPENDENT REACTION (Part 1) 8C

6. PHOTOSYNTHESIS HAPPENS IN CHLOROPLASTS
Proteins that are part of the thylakoid
membrane contain
________________________________ and the ______________ transport chain
Light absorbing CHLOROPHYLL
ELECTRON

7. Light Reaction: Takes place in the Thylakoid membrane
ATP (Energy released)
ATP
Electron Transport
Chain
Pigment/chlorophyl e— H+ H
H2O
e-- H H
NADP O2
waste
ATP
*Don’t have an endless supply of e—
Need to replace H2o
To the Dark side!!!

8. Light Reaction H2O is split O is released to atmosphere
H provides electrons to chlorophyll pigment
Sunlight energy is absorbed by chlorophyll
EXCITES electrons that Jump to electron transport chain

9. Light Reaction
Controlled release of high energy as electrons travel down the electron transport chain (stairs) and form - ATP
At end of Electron Transport Chain (bottom of stairs)
NADP bus picks up H and ATP and goes to the dark side

10. LIVING THINGS NEED ENERGY CARRIERS
Molecule that carries
= _______
Molecule that carries HIGH ENERGY ELECTRONS
= ___________
ATP
NADP+
Images by Riedell

11. HIGH ENERGY ELECTRONS require a special carrier, too
Frying pan image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006
HIGH ENERGY ELECTRONS require a special carrier, too
____________ is one
of the carriers that
cells use to transport
high energy electrons.
NADP+
________ + _____ + _____ → ____________
2 e- H+
_______= nicotinamide adenine dinucleotide phosphate

12. PHOTOSYNTHESIS Light-Dependent Reaction Oxygen Light & Water
ATP
NADPH
Light-Independent
Reactions

13. Light Reaction – in the Thylakoid (grana)
H2O + CO  O2 + C6H12O6
But the NADPH bus & ATP trailer keep rolling
to the Dark Side…….

14. Dark Reaction/Calvin Cycle
in the gooey sticky stroma
CO2
Cycles 6 x
to get 1
Glucose
ATP
Bus back to
Light cycle H
NADP
Back to the
Light Cycle to
recharge
ADP

15. Dark Reaction (Calvin cycle)
NADP bus drops off H and ATP
CO2 is added
Calvin cycle goes around 6 times
Produces 1 glucose molecule

16. H2O + CO2 ----------------- O2 + C6H12O6
Dark Reaction/Calvin Cycle – in the sticky stroma
H2O + CO  O2 + C6H12O6

17. PHOTOSYNTHESIS Light-Dependent Reaction Light & Water Oxygen
ATP
NADPH
glucose
Carbon Dioxide
Light-Independent Reactions
CALVIN CYCLE

18. PHOTOSYNTHESIS OVERVIEW
Pearson Education Inc; Publishing as Prentice Hall

19. LIGHT DEPENDENT REACTION
Requires ______________
Takes place in the ________________
Made up of __________________
and _____________________
Uses light energy to change
ADP + P → _______
NADP+ + 2e- + H + → _________
Breaks apart ______ molecules and releases _____________
LIGHT
THYLAKOID membranes
Chlorophyll
ELECTRON TRANSPORT CHAIN
ATP
NADPH
H20
oxygen

20. CALVIN CYCLE ____________ require ____________
(also called _________________________)
____________ require ____________
Happens in _________ between thylakoids
NADPH donates _______________
ATP donates _________________
CO2 donates ______________
to make __________
LIGHT INDEPENDENT
DOES NOT
LIGHT
STROMA
Hydrogen + electrons
ENERGY
Carbon & oxygen
GLUCOSE

21. Factors that Affect Photosynthesis
AMOUNT OF WATER
____________________
Water is one of the raw materials needed, so
A shortage of water can ________________
photosynthesis
slow or stop
Desert plants and conifers
that live in dry conditions
have a waxy coating on
their leaves to prevent
water loss.

22. Factors that Affect Photosynthesis
TEMPERATURE
Photosynthesis enzymes function best between 0° C - 35° C
At temperatures above or below this range, photosynthesis will slow or stop
Conifers in winter may carry out
photosynthesis only occasionally

23. Factors that Affect Photosynthesis
LIGHT INTENSITY
____________________
More light increases rate of photosynthesis
up to a certain level until plant reaches its
maximum rate of photosynthesis
See effect of light experiment

24. THE BIG PICTURE sugars PHOTOSYNTHESIS provides
the _____________ we breathe
and the __________
heterotrophs (like us)
consume to survive
OXYGEN
sugars
Carbon dioxide
Sugars
WATER
Oxygen
_____________ + ____________ _______________ + ____________