In most cases, that air makes a whistling or wheezing sound as it moves through narrowed passages. Excessive mucus production, shortness of breath, and cough are the other classic symptoms of asthma. But in cough-variant asthma, coughing is the only symptom. It sounds exotic, but it's far from rare.
Definition of photosystem : either of two photochemical reaction centers consisting chiefly of photosynthetic pigments complexed with protein and occurring in chloroplasts: a: one that absorbs light with a wavelength of about 700 nanometers â called also photosystem I b: one that absorbs light with a wavelength of about 680 nanometers â called also photosystem II new!
In (a) photosystem II, the electron comes from the splitting of water, which releases oxygen as a waste product. In (b) photosystem I, the electron comes from the chloroplast electron transport chain. The two photosystems absorb light energy through proteins containing pigments, such as chlorophyll. The light-dependent reactions begin in photosystem II . In PSII, energy from sunlight is used to split water, which releases two electrons, two hydrogen atoms, and one oxygen atom. When a chlorophyll a molecule within the reaction center of PSII absorbs a photon, the electron in this molecule attains a higher energy level.