People who are infected with HIV do not get sick immediately. It can take the body months to attempt to fight off the virus and for a patient to test HIV-positive. So, paradoxically, the period when an HIV-positive person is most infectious coincides with the period he or she is least likely to know their status.
The ATP synthase of mitochondria and chloroplasts is an anabolic enzyme that harnesses the energy of a transmembrane proton gradient as an energy source for adding an inorganic phosphate group to a molecule of adenosine diphosphate (ADP) to form a molecule of adenosine triphosphate (ATP).
ATP is formed when hydrogen ions move down the concentration gradient back to the stroma through ATP synthase. When illuminated, the thylakoid space has a pH of 5 while the stroma has a pH of 8, so there is a substantial pH and H+ concentration difference between the two sides of the thylakoid membrane.