Fractionation of carbon isotopes in oxygenic photosynthesis the bundle sheath cells. Different forms of CCM in phytoplankton include the active uptake of bicarbonate and CO through the cell membrane, the active transport of inorganic carbon from the cellular membrane to the chloroplasts, and active, unidirectional conversion of CO to bicarbonate. The parameters affecting C fractionation in phytoplankton contribute to "δ"C values between -18 to -25‰. Fractionation of carbon isotopes in oxygenic photosynthesis Photosynthesis converts carbon dioxide to carbohydrates via several metabolic pathways that provide energy to an organism and preferentially react with certain stable isotopes of carbon. The selective enrichment of one stable isotope over another creates
Cell signaling precursor cell that continues to divide. The choice of which cell continues to divide is controlled by competition of cell surface signals. One cell will happen to produce more of a cell surface protein that activates the Notch receptor on the adjacent cell. This activates a feedback loop or system that reduces Notch expression in the cell that will differentiate and that increases Notch on the surface of the cell that continues as a stem cell. Many cell signals are carried by molecules that are released by one cell and move to make contact with another cell. "Endocrine" signals are