Photosynthesis Flashcards
Photosynthesis
Capturing solar energy to produce ATP that is used to produce Glucose from H2O and CO2
- Light Energy to Chemical Energy
- Occurs in the Chloroplast
- Carbon Fixation
- Production of atmospheric O2
Chlorophyll A
a photosynthetic pigment
–captures light energy and turns it into chemical energy
Carbon Fixation
Fixing the carbon to put it into a form all other living things can use
What are the 2 sets of reactions for photosynthesis?
- Light Dependent Reactions
- Light Independent Reactions
- -These 2 reactions depend on each other
Light Dependent Reaction
Formation of ATP and NADPH
Light Independent Reaction
Formation of Glucose
Light Dependent Reaction
Formation of ATP and NADPH
Light Independent Reaction
Formation of Glucose
Chloroplasts
- in the mesophyll cells (meat of leaves/plants)
- double membrane
- Stroma
- Thylakoid system
Stroma
Fluid interior inside the second inner most membrane
Thylakoid System
Stacks of membranes
Thylakoid Membrane
Where the light dependent reaction takes place.
–Photosystem I and Photosystem II
Photosystems (PS)
The Light Dependent Reactions
Assemblies of proteins, chlorophyll, and accessory pigment molecules.
Photosystem II and Photosystem I
–They contain the reaction center
–they are connected by the electron transport chain
Photosystem II (PSII)
- pigments trap and pass light energy to the reaction center.
- the reaction center used the energy to give off energized electrons
- transports electrons from PSII to PSI
- uses energy to pump H+ into the thylakoid interior from the stroma
- Absorbed light energy is used to break H2O into CO2 and O2
- -H+ adds to the concentration gradient
- -This is atmospheric O2
Photosystem I (PSI)
- Pigments trap and pass light energy to the reaction center
- reaction center passes energy to incoming electrons to “re-energize” them
- electrons are passed through the 2nd transport system where they combine with NADP and H+ to make NADPH
ATP production in Photosynthesis
Takes place on the thykaloid membrane.
- H+ flows from down the concentration gradient across the thylakoid membrane into the stroma
- -through ATP Synthases
Light Dependent
- Light and H2O go into the light dependent reactions
- ATP, NADPH, and O2(atmospheric) comes out of the light dependent reactions
Reaction center
Gives off energized electrons (Chlorophyll A)
Calvin Cycle
Light Independent Reaction
- Takes place in the Stroma
- CO2, ATP, and NADPH come into it from the light dependent reactions
- Glucose comes out of the light independent reactions
- -NADP and ADP are recycled back into the light dependent reactions
C3 Photosynthesis
Required to make 1 Glucose
- 6 CO2
- 18 ATP
- 12 NADPH
1. Carbon Fixation through Rubisco
2. Phosphoglycerate (PGA)
3. (G3P)
4. RuBP
Rubisco
an enzyme that fixes carbon into (PGA)
Photorespiration
When plants do cellular respiration instead of photosynthesis
- take in more O2 and breath out CO2
- Happens in hot/dry conditions
- The stomata close to conserve water and thus limits the intake of CO2
- If the O2 levels are higher than CO2 then O2 will connect to the Rubisco instead and it will pull Carbon from the Calvin Cycle to make CO2.
- –Thus making little glucose
- C3 plants do not do well in hot/dry climates
C4 Photosynthesis
Sugar cane, corn, and most grasses use this type of photosynthesis.
Separates the Calvin cycle into 2 different cells
-The mesophyll cells fix the carbon then dump it into the bundle sheath cells
- This makes a high concentration of CO2 in the Bundle Sheath Cells so Rubisco will connect with it and run the Calvin Cycle instead of photrespiration
CAM Photosynthesis
Cactus and dry plants
- Hot/dry conditions
- Do the steps at different times
- -Open the stomata at night when it is cooler to take in CO2 and fix it
- -Closes the stomata during the day and runs the Clavin Cycle
