Lesson 5.2 - Pathways of Photosynthesis

Question 1

Define Rubisco

Answer 1

Ribulose 1,5-bisphosphate carboxylase oxygenase; a critical enzyme that acts as a catalyst for the reduction of carbon dioxide in the Calvin cycle of photosynthesis.

Question 2

What is a critical enzyme that acts as a catalyst for the reduction of carbon dioxide in the Calvin cycle of photosynthesis known as?

Answer 2

Rubisco

Question 3

In the light-dependent reactions, _____ absorbs light energy that oxidizes the reaction centre chlorophyll P680, producing the powerful oxidant _____. This molecule oxidizes _____, removing electrons and releasing O₂.

Answer 3

In the light-dependent reactions, photosystem II absorbs light energy that oxidizes the reaction centre chlorophyll P680, producing the powerful oxidant P680⁺. This molecule oxidizes water, removing electrons and releasing O₂​.

Question 4

_____ that are excited by the light energy in photosystem II pass through an _____ transport system to photosystem I. There, the _____ become excited again by the absorption of light, and are ultimately transferred to NADP⁺ as the final _____ acceptor forming _____.

Answer 4

Electrons that are excited by the light energy in photosystem II pass through an electron transport system to photosystem I. There, the electrons become excited again by the absorption of light, and are ultimately transferred to NADP⁺ as the final electron acceptor forming NADPH.

Question 5

These process [of light-dependent reactions in photosynthesis] establish a proton gradient across the thylakoid membrane, which is then used to generate _____ through _____.

Answer 5

These process [of light-dependent reactions in photosynthesis] establish a proton gradient across the thylakoid membrane, which is then used to generate ATP through chemiosmosis.

Question 6

_____ complexes in the thlyakoid membrane harness the energy of the moving protons to produce ATP reactions that are identical to those seen in cellular respiration.

Answer 6

ATP synthase complexes in the thlyakoid membrane harness the energy of the moving protons to produce ATP reactions that are identical to those seen in cellular respiration.

Question 7

In _____ electron transport, electrons can also flow _____ through photosystem I, further building up the H⁺ concentration inside the thylakoid membrane and allowing extra _____ to be produced, but no _____.

Answer 7

In cyclic electron transport, electrons can also flow cyclically through photosystem I, further building up the H⁺ concentration inside the thylakoid membrane and allowing extra ATP to be produced, but no NADPH.

Question 8

In the Calvin cycle, CO₂ is fixed and converted into reduced high-energy organic substances by the addition of electrons and protons that are carried by the _____ produced in the light reaction. _____, also derived from the light reactions, provides additional energy. _____ catalyzes the reaction that first fixes CO₂.

Answer 8

In the Calvin cycle, CO₂ is fixed and converted into reduced high-energy organic substances by the addition of electrons and protons that are carried by the NADPH produced in the light reaction. ATP, also derived from the light reactions, provides additional energy. Rubisco catalyzes the reaction that first fixes CO₂​.

Question 9

For every three complete turns of the Calvin cycle, a single molecule of the 3-carbon molecule _____ is produced. _____ is the starting point for the synthesis of glucose, sucrose, starches, and many other organic molecules.

Answer 9

For every three complete turns of the Calvin cycle, a single molecule of the 3-carbon molecule G3P (glyceraldehyde-3-phosphate) is produced. G3P is the starting point for the synthesis of glucose, sucrose, starches, and many other organic molecules.