Photosynthesis

Question 1

Photosynthesis reaction

Answer 1

6CO₂ + 6H₂O + light -> C₆H₁₂O₆ + 6O₂

Question 2

Photosynthesis is opposite of ______ ____________ which converts ________ into ______ in the form of energy-rich molecule ____.

Answer 2

cell respiration; glucose, energy, ATP

Question 3

Photophosphorylation: process of phosphorylzing ___ with __ to produce ___ using energy in the form of _____.

Answer 3

ADP; P_i; ATP; light

Question 4

Noncyclic photophosphorylation reaction

Answer 4

H₂O + ADP + P_i + NADP⁺ -> ATP + NADPH + H⁺ + O₂

Question 5

Noncyclic photophosphorylation is a light-____________ reaction.

1. Two electrons are excited in photosystem __ (PS __ ).
2. The electrons are passed to the primary electron ________ and move across an _______ _________ _____ (___), losing energy that is used to phosphorylate ___ to ___. In this ETC, approximately ___ ATPs are produced.
3. The electrons are excited again in photosystem __ (PS __ ).
4. The electrons move through a short _____ ______ ____. At the end of this ETC, electrons are incorporated in _____⁺ and _⁺ to produce ________, an energy-rich coenzyme.
5. The electrons absorbed by the energy-rich coenzyme are replenished by ______ splitting:

____ -> 2 _^- + 2 _⁺ + 1/2 _₂.

One species, __⁺ used to produce the energy-rich coenzyme; Another species __^- goes to PSII to replenish loss; Another species __ becomes byproduct.

Answer 5

dependent.

1. Photosystem II (PS II)
2. acceptor; electron transport chain (ETC); ADP to ATP; 1.5
3. Photosystem I (PSI)
4. electron transport chain; NADP⁺ and H⁺ to produce NADPH.
5. water; H₂O _-> 2e^- + 2H⁺ + 1/2O₂;

Question 6

Cyclic Photophosphorylation (2 differences from noncyclic photophosphorylation)

Answer 6

1. the two electrons are returned to PS I instead of reducing NADP⁺ to NADPH. They are re-energized by light PS I and go through the ETC.
2. In cyclic photophosphorylation, 1 ATP is generated from two electrons.

Question 7

Calvin Cycle: general idea

Answer 7

Fixes atmospheric CO₂ into organic glucose using energy molecules from photophosphorylation.

Question 8

Calvin Cycle is also known as C₃ photosynthesis because the primary molecule that CO₂ is converted into has 3 carbons. This molecule is called _____________ (_ _ _).

Answer 8

Phosphoglycerate (PGA)

Question 9

Calvin Cycle steps:

1. Carboxylation: 6CO₂ + 6____ (Ribulose biphosphate) combine to form 12 ___ (phosphoglycerate), catalyzed by enzyme ________.
2. Reduction: 12 ___ reduced to 12 ___ (glyceraldehyde-3-phosphate) with energy from 12 ___ and 12 _____.
3. Regeneration: 10 ___ converted to 6 ____ using energy from 6 ___.
4. Carbohydrate synthesis: 2 ___ forms 1 _______.

Answer 9

1. RuBP; PGA; Rubisco
2. PGA; G3P; ATP; NADPH
3. G3P; RuBP; ATP
4. G3P; glucose

Question 10

Calvin Cycle reaction:

Answer 10

6CO₂ + 18ATP + 12NADPH -> 18ADP + 18P_i + 12NADP⁺ + 1C₆H₁₂O₆

Question 11

Photosynthesis and other biosynthetic pathways are not ________. They are catalyzed by _____.

Answer 11

spontaneous; enzymes such as rubisco and carboxylase and ATP synthases

Question 12

Chloroplast - draw and label contents:

1. outer membrane
2. intermembrane spalce
3. inner membrane
4. stroma - where _____ _____ occurs
5. granum
6. thylakoid - where __________ occur and where the molecules ___ and ___ are located along with electron acceptor and carrier protien ________.
7. thylakoid lumen - where _____ accumulate and ______ occurs

Answer 12

4. Calvin Cycle
5. photophosphorylations; P₆₈₀ and P₇₀₀; cytochrome
6. H⁺; chemiosmosis

Question 13

Chemiosmosis is the process of generating ___ through a ______ gradient. This occurs in the ________ and involves __ ions from the _______ during the ______ ______ and _________ during the _______ and ______ _________________.

Answer 13

ATP; proton.

thylakoid/thylakoid lumen; H⁺; stroma; Calvin cycle; thylakoid; noncyclic and cyclic photophosphorylations.

Question 14

Chemiosmosis steps:

1. __ accumulate inside the _____ ____. The __ are from water splitting that occurs during ___________ by ___. The __ are also transferred by the ETCs of PSII and PSI.
2. ___ and _____ gradients are created. Inside the thylakoid lumen, the pH is _____ and outside in the stroma, the pH is ____.
3. ____ _______ enzyme generates ____. This enzyme is a channel protein and uses _ ____s to produce 1 ___.
4. The ___ generated by chemiosmosis is used in the _____ ____.

Answer 14

1. H⁺; thylakoid lumen. H⁺; photophosphorylation by PSII. H⁺.
2. pH and electrical; low; high.
3. ATP synthase; ATP; 3 H⁺s to produce 1 ATP.
4. ATP; Calvin Cycle.

Question 15

Photorespiration:

1. _______ is the most common protein on earth.
2. This enzyme doesn’t favor catalysis of CO₂ over O₂, which causes problems. Photorespiration is the fixing of ___.
3. Photorespiration creates two problems: 1) It lowers the amount occurence of the ______ _____, thus lowering efficiency of photosynthesis. 2) It produces byproducts that the cell has to use additional energy to breakdown. Organelles such as _______ break down byproducts of photorespiration.

Answer 15

1. Rubisco
2. O₂
3. Calvin Cycle; peroxisomes

Question 16

C₄ Photosynthesis: ________ segregating photosynthesis. Moves CO₂ through _________ from ________ _____ to _______ _____ _____ where little ____ exists and little ___________ can occur.

CO₂ combines with ___ (phosphoenolpyruvate) to produce four-carbon ___ (oxaloacetate), catalyzed by ____ __________ enzyme. ___ converted to ______ which is shuttled through the _______ into the _____ ____ ____. ______ is then converted to ______ which is shuttled back to the ______- _____ and converted into ___.

Answer 16

spatial.

plasmodesmata; mesophyll cells; bundle sheath cells; O₂; photorespiration.

PEP; OAA; PEP carboxylase. OAA; malate; plasmodesmata; bundle sheath cells.

Malate; pyruvate; mesophyll cells; PEP.

Question 17

CAM photosynthesis: _______ segregated.

At night, the stomata opens, PEP carboxylase is active and _____ ____ accumulates in the _______. In the day, the stomata is closed and accumulated _____ ____ is shuttled out of the ______ and converted to ___, releasing ____.

Answer 17

temporally.

malic acid; vacuole.

malic acid; vacuole; OAA; CO₂