You are familiar with the electron transport system in photosynthesis that takes light energy and converts it to chemical bond energy in the form of ATP and NADPH. This electron transport chain in cellular respiration will take the energy stored in NADH and FADH2 during the Krebs cycle and convert it to chemical bond energy in the form of ATP. In eukaryotes, this reaction takes place on the inner mitochondrial membrane. Prokaryotes that undergo aerobic respiration also have an electron transport chain located within their plasma membrane, which may be highly folded similar to the inner membrane of the mitochondrion.
tropism is a turning toward or away from a stimulus in the environment. Growing toward gravity is called geotropism. Plants also exhibit phototropism, or growing toward a light source. This response is controlled by a plant growth hormone called auxin.
