1. Chapter 7
Photosynthesis

2. 7.1 Autotrophs are the Producers of the Biosphere
Make their own food through process of Photosynthesis
Sustain themselves
Do not usually consume organic molecules derived from other organisms
Photoautotrophs use energy of light to produce organic molecules
Chemoautotrophs are prokaryotes that use inorganic chemicals as their energy source
Heterotrophs are consumers that feed on
Plants
Animals
Decompose organic material

3. 7.1 Photosynthesis in plants Takes place in Chloroplasts
Coverts Carbon Dioxide and Water into organic molecules
Releases oxygen

4. 7.2 Photosynthesis occurs in Chloroplasts in plant cells
Chloroplasts are the major sites of photosynthesis in green plants
Chlorophyll
Important light-absorbing pigment in Chloroplasts
Responsible for green color of plants
Plays central role in converting solar energy to chemical energy
Chloroplasts are concentrated in the cells of the Mesophyll, the green tissue in the interior of the leaf
Stomata (singular: Stoma) are tiny particles in leaf that allow
Carbon Dioxide to enter
Oxygen to exit

5. 7.2 Veins in leaf deliver water absorbed by the roots
Chloroplasts consist of an envelope of 2 membranes (Endosymbiont Theory) which
Enclose an inner compartment filled with thick fluid called Stroma
Contain system of interconnected membranous sacs called Thylakoids

6. 7.2 Thylakoids Chlorophyll molecules
Often concentrated in stacks called Grana
Have an internal compartment called the thylakoid space, which has functions analogous to the intermembrane space of a mitochondrian
Thylakoid membranes also house much of the machinery that converts light energy to chemical energy
Chlorophyll molecules
are built into the thylakoid membrane
capture light energy

7. 7.4 Photosynthesis is a Redox Process, as is Cellular Respiration
Photosynthesis, like Cellular Respiration, is a redox (oxidation-reduction) process
CO2 becomes reduced to sugar as electrons along with Hydrogen ions from H2O are added to it
H2O molecules are oxidized when they lose electrons along with Hydrogen ions

8. 7.9 Chemiosmosis powers ATP synthesis in the light reactions
In photophosphorylation, using the initial energy input from light
The electron chain pumps H+ into the thylakoid space
The resulting concentration gradient drives H+ back through ATP synthase, producing ATP

9. Notes on Cellular Respiration
In cellular respiration the energy comes from oxidation of Glucose
In photosynthesis it comes from sunlight, hence phosphorylation
Mitochondria use oxidative phosphorylation to transfer chem energy from food into chem energy of ATP

10. Light Dependent Reaction
Inputs: H2O and Sun (and ADP and NADP+)
Outputs: ATP and NADPH (and O2)
Took energy from sun and made it into chemical energy

11. Calvin Cycle
Reducing CO2 to Sugar

12. 7.10 ATP and NADPH power sugar synthesis in the Calvin Cycle
Calvin cycle makes sugar within a chloroplast
To produce sugar the ingredients are: atmospheric CO2 and ATP and NADPH (generated by the light reactions)
The Calvin Cycle uses these 3 ingredients to produce an energy-rich, 3-Carbon sugar called Glyceraldehyhde – 3-phosphate (G3P)
A plant cell may then use G3P to make Glucose and other organic molecules

13. Steps of Calvin Cycle 1. Carbon Fixation 2. Reduction
3. Release of one molecule of G3P
4. Regeneration of starting molecule (Rubp)