1. Where does photosynthesis take place?
Leaves : the photosynthetic organs of the plant
Mesophyll: main photosynthetic tissue
a. Palisade layer: full of chloroplasts
b. Spongy layer: fewer chloroplasts and
many air spaces

2. What are the reactants and products of photosynthesis?
Light
CO2 + H2O  O2 + 3 C sugar
chlorophyll
Light-dependent reactions = convert light energy to the chemical energy of ATP which occur in the thylakoid membranes of the chloroplast.
Calvin Cycle = using the products of the light reactions to convert carbon dioxide and water to sugars. These reactions occur in the stroma of the chloroplast.

3. Why is Chlorophyll Necessary?
Pigments that are capable of absorbing portions of visible light chlorophyll a and chlorophyll b absorb the blue and red spectrum and reflect the green
The double bonds in the molecule release electrons when light hits them

4. Why Leaves Change Color?
A color palette needs pigments, and there are 3 types:
1. Chlorophyll a & b
2. Xanthophyll
3. Carotenoids

5. Chloroplast Structure?
Stroma – large central compartment, where Calvin cycle takes place
Thylakoids – flattened sacs within stroma that contain chlorophyll
Grana – stacks of thylakoids
Thylakoid space – within thylakoid, where light reactions take place

6. What is the first Set of reactions of photosynthesis?
Light dependent reactions-
A)occurs in thylakoid membrane
B)pigments release electrons as light hits Photosystems
C) Photolysis occurs
Chemical energy products are made that are used in the next set of reactions

7. What are photosystems?
pigment complex that serves as antennae to gather solar energy
embedded into the thylakoid membrane
energy is passed from one pigment to the next until it reaches chlorophyll a
electrons escape as they become excited

8. Light-Dependent Reactions
1. PSII absorbs energy and transfers e- to PSI
2. Light energy causes water to split (called photolysis)
Thus giving off O2 AND electrons
– Those electrons replace those lost by PSII
3. The electrons move through the ETS and H+
from water is carried into thylakoid space
4. The electrons from PSI are then picked up by NADP
reductase.
The H+ that has built up in the thylakoid space diffuses through ATP synthase(a protein) which helps form ATP (chemical energy)
The H that is now out in the stroma also gets picked up by NADP and changes NADP to NADPH
7. The products : ATP and NADPH move to Calvin cycle

10. Overview of Light-Dependent Reactions

11. How is the chemical energy formed? Calvin Cycle
CO2 diffuses into leaf through the stomata and is fixed by RuBp(5C) = 6C
This is called: Carbon Fixation
This is unstable and splits into 2 (3C)molecules called PGA
PGA uses a Phosphate (P) from ATP (made in light reactions) to form PGAP
PGAP is converted to PGAL with the H from NADPH (made in Light reactions)
PGAL is converted to RuBP and sugar

12. Calvin Cycle CO2 is brought in by diffusion - through the stomata
- controlled by the turgor pressure of
the guard cells
CO2 combines with 5 carbon RuBP
ribulose biphosphate
1st step/ Called: Carbon Fixation
Catalyzed by enzyme called Rubisco

13. Calvin Cycle (cont’d) Occurs in the stroma of the Chloroplast
Powered by light reactions
NADPH2
ATP
Three turns of cycle, each picking up CO2, makes six molecules of PGAL
Five molecules of PGAL go to make more RuBP
One molecule goes to make sugar

16. OVERALL PHOTOSYNTHESIS
Oxidation-loss of electron coupled with loss of hydrogen proton Reduction- gain of electron coupled with gain of hydrogen proton

17. Rates of Photosynthesis (limiting factor)
Four things affect rate of P.S.
Light intensity increases rate of p.s. up to light saturation point
as temperature increases, p.s. rate increases to point, then decreases
concentration of CO2 increases rate of p.s.
as oxygen increases, p.s. rate decreases

18. Photorespiration
If there is a higher concentration of oxygen than carbon dioxide, the enzyme rubisco binds with oxygen and combines with RuBP which converts it to 1 PGA molecule and glycolate.
PGA will eventually be used to form simple sugar
Glycolate is transported out of chloroplast and eventually releases CO2.
No new CO2 is fixed and RuBP releases CO2(like respiration)

20. What is advantage of C4 plants?
Can reduce amount photorespiration because CO2 is delivered to
bundle sheath cells that have chloroplasts

21. Heat adaptations
C4 plants such as sugarcane, corn, and crabgrass use specialization of fixing carbon
Bundlesheath surrounds vein and mesophyll cells surround sheath
Mesophyll cell fixes carbon producing 4 carbon molecule
4 carbon molecule transported to bundlesheath where it is converted to CO2
Increases efficiency by reducing photorespiration

22. What is the advantage of partitioning space in a C4 plant?
Avoid photorespiration and can keep stomates open longer
CO2 is converted to oxaloacetate and delivered to bundle
sheath cells
water is lost as stomates are opened

23. Heat Adaptations CAM Found in snake plants, jade, and cactus
Allow s for stomates to be open at night
Stores CO2 chemically for use when light is out
Slow growers

24. What is the advantage of partitioning in time?
Can keep stomates open longer because CO2 is stored
as malate in vacuoles during the evening and used by
Calvin cycle at night
Stomates closed during day