Question: where are protons pumped in electron transport chain
[{'answer': 'across the mitochondrial inner membrane', 'provenance': [{'wikipedia_id': '92236', 'title': 'Electron transport chain', 'start_paragraph_id': 33, 'start_character': 231, 'end_paragraph_id': 33, 'end_character': 270, 'bleu_score': 1.0, 'section': 'Section::::In mitochondria.:Summary.\n'}]}, {'provenance': [{'wikipedia_id': '92236', 'title': 'Electron transport chain', 'start_paragraph_id': 33, 'start_character': 0, 'end_paragraph_id': 33, 'end_character': 404, 'bleu_score': 0.9694566079002921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16343739056184060419}, 'section': 'Section::::In mitochondria.:Summary.\n'}]}]