Unit Five - Energetics - Photosynthesis Flashcards
What is the equation for photosynthesis? (4)
- 6C02 + 6H20 = C6H12O6 + 602
- Chloroplasts absorb sunlight (=)
- H20 - Oxidized to form O2
- C02 - Reduced into C6H12O6
What do chloroplasts do in photosynthesis? (2)
- Transforms light energy into glucose bonds (ATP)
- Changes inorganic molecules (CO2) to organic molecules (glucose)
Where does photosynthesis occur?
Leaves of autotrophs
What are autotrophs?
Producers/Organisms make their own food
What are the two parts that make up cholorplasts?
Grana and Stroma
What is Grana? (3)
- Stack of Thylakoids
- Light Dependent Rxn
- Sunlight to ATP
What is Stroma? (3)
- Fluid Filled Space
- Light Independent Rxn
- 6C02 is reduced to Glucose
What is a thylakoid? (4)
- Photosynthetic Membrane
- Contains Chlorophyll Pigment
- Site of Light Dependent Reactions
- Capture & converts light to ATP & Nadph
(Made up of multiple proteins/Protein Complex)
What does it mean when something is oxidized?
Loss of e- and hydrogen
What are redox reactions? (3)
- Oxidation & Reduction
- Oxidation - Loss of e- & hydrogen
- Reduction - Gain of e- & hydrogen
What are the two main reactions/stages of Photosynthesis? (2)
- Light Dependent Rxn (Thylakoid Mem.)
- Light Independent Rxn (Stroma)
What are Photosynthetic Membranes also called?
Thylakoids
What happens to the rate of photosynthesis as light intensity increases? (2)
- Increases then levels off
- Photosystems/Photosynthetic Enzymes are fully saturated
What happens to the rate of photosynthesis as concentration of carbon dioxide increases? (2)
- Increases then levels off
- Photosystems/Photosynthetic Enzymes are fully saturated
(Light independent reactions are actually dependent on the light dependent reaction in order to revieve the ATP and NADPH, so it will only goes as fast as the light reaction)
What happens to the rate of photosynthesis as temperature increases? (2)
- Increases to Opt. Temp, then decreases
- Enzyme will denature (breaking bonds in 2nd, 3rd and 4th), changing its shape & function
What are Photons of Light?
Particles carrying light energy
What are photosystems? (3)
- Located in Thylakoid Membranes
- Complexes of Protein & Pigment
- Absorb Light Energy & Excite e-
What is the primary function for Photosystem II?
- Initiates Photolysis (replaces lost e-)
- Initiates Electron Transport Chain
What is the primary function for Photosystem I?
Re energizes e- for the ETC
What is Photolysis? (3)
- H2O is split
- 2H+, O2, and e-
- To replace the electrons lost by PSII
What are accessory pigments? (5)
- Absorbs light energy
- Bounces from acc. p to acc. p
- To dissipate heat over a large SA
- E targets & excites e- (WILL NOT OVERHEAT)
- Absorbs ALL wavelengths of light
What is the Electron Transport Chain? (6)
- Series of Proteins in Thylakoid Membrane
- Excited e- is transferred
- To a primary electron acceptor
- As e- goes thru ETC, it loses energy
- e- is in a lower energy state
- e- is re-energized by PSI
(Later transferred to another primary electron acceptor and reduces NADP+ to NADPH)
What is the Calvin Cycle?
CO2 is converted into glucose using ATP and e- from NADPH
What is NADP+ and NADPH?
NADP+: Coenzyme that is an e- carrier
NADPH: Reduced NADP+ (carries high energy e- to the calvin cycle)
How is light energy transformed into NADPH? (10)
- LE is absorbed by PSII & I
- LE is absorbed by the Accessory Pigments
- Energy bounces from pigment to pigment
- Targets e-and becomes excited
- Transferred to Primary e- Acceptor in PSII
- e- goes down ETC
- Loses energy
- Re energized by light in PSI
- Goes down ETC & transferred to NADP+
- NADP+ reduced to NADPH
What is ATP Energy used for in Photosynthesis?
Form Glucose Bonds
What is ATP Synthase? (2)
- Enzyme embedded in Thylakoid Mem.
- Synthesis ATP from ADP
- Transports H+ Ions
What does H+ have to do in photosynthesis? (8)
- Energy from excited e- in ETC
- Actively Transports H+
- From Stroma (lo) to the Thylakoid (hi)
- Difference in concentation creates potential energy
- Accumulation of H+ creates a diff. in charge inside and outside the membrane
- Forming Voltage
- H+ will flow back into ATP Synthase and spin it like a turbine
- This provides enough energy for the ATP Synthase to convert ADP into ATP
When does the stomata open and close? (4)
- Guard Cells Open in the Light
- Guard Cells Close in the Dark
- Freshwater Opens the Stomata
- Saltwater closes the stomata
How is NADPH used and NADP+ recycled?
How is ATP used and ADP recycled?
- NADPH provides H and e- to calvin cycle
- NADP+ is produced from the rxn
- ATP donates a phosphate & E
- Forming ADP
What are these proteins that are embedded in the Electron Transport Chain? (3)
- Reduced & oxidized in a cycle (spins)
- Gains E released from e-
- Forms a proton gradient/membrane potential
How is atp synthesized in the chloroplast? (4)
- H+ was actively pumped in ETC
- Diffuses thru ATP Synthase
- Protein spins, opening bonding site
- ADP bonds w/ inorg. P (ATP)
What are the 3 stages of the Calvin Cycle?
- Carbon Fixation
- Reduction
- Regeneration of Ribulose
What is Carbon Fixation in the Calvin Cycle? (5)
Goal: Produce 3 PGA (6 molecules)
3 CO2 IS THE REACTANT, SO IT OCCURS 3X
1. 3Co2 combine with ribulose (5 Carbon Sugar)
2. Using enzyme RuBisCO
3. Forms unstable 6 carbon compound
4. Splits to 2 molecules
5. Called 3 PGA (3 - Phosphoglycerate)
What is Reduction in the Calvin Cycle? (5)
Goal: Produce G3P (6 molecules)
1. 3 PGA receives a Phosphate from 6ATP
2. 6 ATP to 6 ADP
4. Receives H & e- from NADPH
5. Becomes G3P
What is 6ATP for in Reduction for the Calvin Cycle?
- PROVIDES ENERGY
- Opens bonding site
- To combine w/ H from the NADPH
- Essentially forming glucose bonds
How was glucose formed in the Calvin Cycle? (4)
- 5 GP3 Mol. regenerate ribulose
- 1 GP3 Mol. is used for netgain
- 1 GP3 Mol. form 1/2 of a glucose mol.
- Two cycles are needed to form 1 glucose
(6CO2, 12 GP3, 2 GP3 for glucose, 10 GP3 for Regeneration)
How is RuBp regenerated in the Calvin Cycle? (2)
- 3 ATP donates P & E
- Combines w/ carbons in diff ways to produce ribulose
How many production line are going on at the same time?
How many carbons exist from all of these production lines?
How many is used for regeneration of glucose?
How many is used for regeneration of RuBP?
- 6
- 36
- 6
- 30
