Question

drag the labels to the appropriate locations on the diagram of the thylakoid membrane.
note: one target of group 1 and one target of group 2 should be left empty.
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h+ diffuses
across
membrane
h+ pumped
across
membrane
atp
synthesis
h+
release
group 2
group 2
group 1
group 1
group 1
group 1
group 2
group 2
h2o
ps ii
cytochrome
complex
ps i
nadp+
reductase
atp
synthase
stroma
thylakoid space

Explanation:

• In the thylakoid membrane, during the light - dependent reactions of photosynthesis:
• At PS II (Photosystem II), water (\(H_2O\)) is split. This releases \(H^+\) (protons) into the thylakoid space. So, the label "site of \(H^+\) release" (Group 2) should be placed near the \(H_2O\) input to PS II.
• The cytochrome complex pumps \(H^+\) across the membrane (from the stroma to the thylakoid space). So, the label "\(H^+\) pumped across membrane" (Group 1) should be placed near the cytochrome complex.
• At ATP synthase, \(H^+\) diffuses across the membrane (from the thylakoid space to the stroma) and this is the site of ATP synthesis. So, the label "\(H^+\) diffuses across membrane" (Group 1) should be placed near ATP synthase and "site of ATP synthesis" (Group 2) should be placed near ATP synthase.

Answer:

• Group 1 (left - hand empty): \(H^+\) pumped across membrane (cytochrome complex), \(H^+\) diffuses across membrane (ATP synthase)
• Group 2 (right - hand empty): site of \(H^+\) release (PS II), site of ATP synthesis (ATP synthase)