Unit Five - Energetics - Photosynthesis

Question 1

What is the equation for photosynthesis? (4)

Answer 1

1. 6C02 + 6H20 = C6H12O6 + 602
2. Chloroplasts absorb sunlight (=)
3. H20 - Oxidized to form O2
4. C02 - Reduced into C6H12O6

Question 2

What do chloroplasts do in photosynthesis? (2)

Answer 2

1. Transforms light energy into glucose bonds (ATP)
2. Changes inorganic molecules (CO2) to organic molecules (glucose)

Question 3

Where does photosynthesis occur?

Answer 3

Leaves of autotrophs

Question 4

What are autotrophs?

Answer 4

Producers/Organisms make their own food

Question 5

What are the two parts that make up cholorplasts?

Answer 5

Grana and Stroma

Question 6

What is Grana? (3)

Answer 6

1. Stack of Thylakoids
2. Light Dependent Rxn
3. Sunlight to ATP

Question 7

What is Stroma? (3)

Answer 7

1. Fluid Filled Space
2. Light Independent Rxn
3. 6C02 is reduced to Glucose

Question 8

What is a thylakoid? (4)

Answer 8

1. Photosynthetic Membrane
2. Contains Chlorophyll Pigment
3. Site of Light Dependent Reactions
4. Capture & converts light to ATP & Nadph

(Made up of multiple proteins/Protein Complex)

Question 9

What does it mean when something is oxidized?

Answer 9

Loss of e- and hydrogen

Question 10

What are redox reactions? (3)

Answer 10

1. Oxidation & Reduction
2. Oxidation - Loss of e- & hydrogen
3. Reduction - Gain of e- & hydrogen

Question 11

What are the two main reactions/stages of Photosynthesis? (2)

Answer 11

1. Light Dependent Rxn (Thylakoid Mem.)
2. Light Independent Rxn (Stroma)

Question 12

What are Photosynthetic Membranes also called?

Answer 12

Thylakoids

Question 13

What happens to the rate of photosynthesis as light intensity increases? (2)

Answer 13

1. Increases then levels off
2. Photosystems/Photosynthetic Enzymes are fully saturated

Question 14

What happens to the rate of photosynthesis as concentration of carbon dioxide increases? (2)

Answer 14

1. Increases then levels off
2. 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)

Question 15

What happens to the rate of photosynthesis as temperature increases? (2)

Answer 15

1. Increases to Opt. Temp, then decreases
2. Enzyme will denature (breaking bonds in 2nd, 3rd and 4th), changing its shape & function

Question 16

What are Photons of Light?

Answer 16

Particles carrying light energy

Question 17

What are photosystems? (3)

Answer 17

1. Located in Thylakoid Membranes
2. Complexes of Protein & Pigment
3. Absorb Light Energy & Excite e-

Question 18

What is the primary function for Photosystem II?

Answer 18

1. Initiates Photolysis (replaces lost e-)
2. Initiates Electron Transport Chain

Question 19

What is the primary function for Photosystem I?

Answer 19

Re energizes e- for the ETC

Question 20

What is Photolysis? (3)

Answer 20

1. H2O is split
2. 2H+, O2, and e-
3. To replace the electrons lost by PSII

Question 21

What are accessory pigments? (5)

Answer 21

1. Absorbs light energy
2. Bounces from acc. p to acc. p
3. To dissipate heat over a large SA
4. E targets & excites e- (WILL NOT OVERHEAT)
5. Absorbs ALL wavelengths of light

Question 22

What is the Electron Transport Chain? (6)

Answer 22

1. Series of Proteins in Thylakoid Membrane
2. Excited e- is transferred
3. To a primary electron acceptor
4. As e- goes thru ETC, it loses energy
5. e- is in a lower energy state
6. e- is re-energized by PSI
   (Later transferred to another primary electron acceptor and reduces NADP+ to NADPH)

Question 23

What is the Calvin Cycle?

Answer 23

CO2 is converted into glucose using ATP and e- from NADPH

Question 24

What is NADP+ and NADPH?

Answer 24

NADP+: Coenzyme that is an e- carrier
NADPH: Reduced NADP+ (carries high energy e- to the calvin cycle)

Question 25

How is light energy transformed into NADPH? (10)

Answer 25

1. LE is absorbed by PSII & I 2. LE is absorbed by the Accessory Pigments 3. Energy bounces from pigment to pigment 4. Targets e-and becomes excited 5. Transferred to Primary e- Acceptor in PSII 6. e- goes down ETC 7. Loses energy 8. Re energized by light in PSI 9. Goes down ETC & transferred to NADP+ 10. NADP+ reduced to NADPH

Question 26

What is ATP Energy used for in Photosynthesis?

Answer 26

Form Glucose Bonds

Question 27

What is ATP Synthase? (2)

Answer 27

1. Enzyme embedded in Thylakoid Mem. 2. Synthesis ATP from ADP 3. Transports H+ Ions

Question 28

What does H+ have to do in photosynthesis? (8)

Answer 28

1. Energy from excited e- in ETC 2. Actively Transports H+ 3. From Stroma (lo) to the Thylakoid (hi) 4. Difference in concentation creates potential energy 5. Accumulation of H+ creates a diff. in charge inside and outside the membrane 6. Forming Voltage 7. H+ will flow back into ATP Synthase and spin it like a turbine 8. This provides enough energy for the ATP Synthase to convert ADP into ATP

Question 29

When does the stomata open and close? (4)

Answer 29

1. Guard Cells Open in the Light 2. Guard Cells Close in the Dark 3. Freshwater Opens the Stomata 4. Saltwater closes the stomata

Question 30

How is NADPH used and NADP+ recycled? How is ATP used and ADP recycled?

Answer 30

1. NADPH provides H and e- to calvin cycle 2. NADP+ is produced from the rxn 3. ATP donates a phosphate & E 4. Forming ADP

Question 31

What are these proteins that are embedded in the Electron Transport Chain? (3)

Answer 31

1. Reduced & oxidized in a cycle (spins) 2. Gains E released from e- 3. Forms a proton gradient/membrane potential

Question 32

How is atp synthesized in the chloroplast? (4)

Answer 32

1. H+ was actively pumped in ETC 2. Diffuses thru ATP Synthase 3. Protein spins, opening bonding site 4. ADP bonds w/ inorg. P (ATP)

Question 33

What are the 3 stages of the Calvin Cycle?

Answer 33

1. Carbon Fixation 2. Reduction 3. Regeneration of Ribulose

Question 34

What is Carbon Fixation in the Calvin Cycle? (5)

Answer 34

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)

Question 35

What is Reduction in the Calvin Cycle? (5)

Answer 35

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

Question 36

What is 6ATP for in Reduction for the Calvin Cycle?

Answer 36

1. PROVIDES ENERGY 2. Opens bonding site 3. To combine w/ H from the NADPH 4. Essentially forming glucose bonds

Question 37

How was glucose formed in the Calvin Cycle? (4)

Answer 37

1. 5 GP3 Mol. regenerate ribulose 2. 1 GP3 Mol. is used for netgain 3. 1 GP3 Mol. form 1/2 of a glucose mol. 4. Two cycles are needed to form 1 glucose (6CO2, 12 GP3, 2 GP3 for glucose, 10 GP3 for Regeneration)

Question 38

How is RuBp regenerated in the Calvin Cycle? (2)

Answer 38

1. 3 ATP donates P & E 2. Combines w/ carbons in diff ways to produce ribulose

Question 39

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?

Answer 39

1. 6 2. 36 3. 6 4. 30