1. ‘The light at the end of the tunnel’
Photosynthesis
‘The light at the end of the tunnel’

2. A two step process Light STEP 1 = Light dependent stage
(red and blue wavelengths absorbed, green reflected) pigment chlorophyll, hydrogen and CO2
STEP 1 = Light dependent stage
(requires light)
STEP 2 = Light independent stage

3. Structures Chloroplast The structure where photosynthesis takes place.
See Biozone pg 299
Chloroplast
The structure where photosynthesis takes
place.
Inside the chloroplast:
Grana – membranes that contain the pigment chlorophyll (site of light dependent stage)
Stroma – liquid inside chloroplast (site of light independent stage = Calvin cycle)

4. Step 1 Light dependent stage (energy capture):
The light strikes chlorophyll and creates a
series of reactions, the energy is converted
into ATP (photophosphorylation) and
NADPH.
Water is split in the process releasing O2.
Occurs in the Grana

5. Step 2 Light independent stage (carbon fixing):
CO2 from the atmosphere or water is captured and modified by the addition of hydrogen to form carbohydrates (carbon fixing).
Energy to do this comes from step 1.
The Calvin cycle allows for carbon fixing to occur. Six CO2 molecules enter the Calvin cycle, eventually producing 1 glucose.
Occurs in the stroma.

6. Light independent stage
ATP and ADP
(ATP)
Light dependent stage
NADPH
(ADP)
Light independent stage
NADP

7. Cellular respiration
Then the process of cellular respiration occurs using the glucose produced by photosynthesis.
Plants carry out cellular respiration so energy is released for all of their metabolic reactions.

8. Questions
_______ and ________ wavelengths are absorbed by chlorophyll.
The energy capture stage of photosynthesis occurs where in the chloroplast ____________ .
Carbon fixing stage of photosynthesis occurs where in the chloroplast ______ .
In which stage is water split ________
____________

9. Questions cont….
5) Why are most photosynthetic organisms green __________________________ .
6) In stage two where does the CO2 come from _______________ and _________ .
7) What is the importance of the Calvin cycle in relation to respiration _____________ .
8) Why is photosynthesis fundamental to life _________________________________