5.2.1 Photosynthesis

Question 1

Structure of chlorophyll

Answer 1

• Contains Mg 2+ group

- Not a protein

Question 2

Structure of Chloroplast

Answer 2

• Double membraned
• Thylakoid discs stacked to form grana (singular granum) (site of LDS)
• Grana are joined together by lamellae (membranous channels)
• Complexes of pigments embedded in the thylakoids absorb light
• Fluid enclosed is called the stroma

Question 3

Where does the LDS occur?

Answer 3

Within and across the thylakoid membranes

Question 4

Where does the LIS (Light Independent stage) occur?

Answer 4

• Stroma

Question 5

What are the reactants and products in 1 turn of the Calvin cycle?

Answer 5

• 1 CO2
• 1 RuBP
• Unstable (6 - C) intermediate
• 2 GP (3 - C)
• 2 NADPH (ATP)
• 2 TP (3 - C)

Question 6

Calvin Cycle summary

Answer 6

• Carbon Fixation - rubisco enzyme catalyses the reaction between RuBP and CO2
• Reduction - GP is reduced by NADPH with ATP energy to TP
• Regeneration - RuBP is regenerated with the remaining TP

Question 7

What products from the LDS is needed for the Calvin Cycle to continue?

Answer 7

• NADPH (reduced NADP)

- ATP

Question 8

How are electrons transported across in the LDS?

Answer 8

• Electron transport chain

Question 9

What is the final electron acceptor in the LDS?

Answer 9

NADP+

Question 10

How is ATP produced in the LDS? (Chem osmosis steps)

Answer 10

• Energy from the movement of electrons through the transport chain is used to pump H+ ions into the Thylakoid space
• High concentration of H+ in the thylakoid space compared to stroma forming an ELECTROCHEMICAL GRADIENT
• H+ moves via facilitated diffusion through ATP synthase forming ATP (Chemiosmosis)