Blogpost #6- Lauren A.

Our plants have gained biomass and gotten bigger. They did this by having its cells divide through mitosis, this process requires to collect/create sugar for energy. To collect sugar the plant performs photosynthesis which converts CO2 and water into O2 and sugar. Photosynthesis has two main parts, light dependent reactions and light independent reactions also known as the Calvin cycle. The light dependent reactions are partially self explanatory. The reaction turns water, sunlight, NADPH2 and ADP into O2, NADP+ and ATP. The O2 leaves the cell and the NADP+ and ATP go through the Calvin cycle. The Calvin cycle uses CO2 as a source of carbon to regenerate chains of carbon and other atoms into parts that form sugars. It is able to reuse the chains by breaking bigger chains into two smaller ones and then regenerating them into full chains again. Some of which will get reused and regenerated again and again and others that become finished sugars. The sugar acts as a form of stored energy. To access this energy all cells need to be able to perform a process called cellular respiration. Cellular respiration turns the energy stored in sugar into a usable energy in the cell, ATP. It produces ATP at 3 steps in cellular respiration, after glycolysis which occurs in the cytoplasm and turns a glucose sugar into 2 ATP, cytosol and pyruvate. The pyruvate is then broken down in the mitochondria, through the Krebs cycle which functions as the opposite of the Calvin Cycle. It results in 2 more ATP and free electrons carried by NADH and other molecules. These go through the last step which is a complicated combination of an electron transport chain and oxidative phosphorylation, which creates the bulk of the ATP, roughly 34. Now with a way to store energy in the form of sugars and a way for the energy to be extracted from the sugar and become usable, the sugars can then be moved to cells that don't produce sugar so all cells in the plant can grow and perform mitosis, the process in which a cell undergoes to replicate/split itself into two new daughter cells. It does this by condensing the DNA into chromosomes and having them align at the center of the nucleus. The nucleus begins to break down and spindle fibers form from some organelles known as centrioles, placed on opposite sides of the cell, reach out and "pull" the chromosomes in half and to their respective side of the cell so each new daughter cell will have a copy of the DNA. The cell then splits down the middle through cytokinesis while nucleus's reform the new daughter cells, leaving you with two new cells roughly half the size of the original. To undergo mitosis the cell must duplicate the DNA in the cell which it does using the enzymes DNA synthase and helicase. Helicase unwinds and splits the DNA so DNA synthase can take each strand and add complementary bases to each side creating two new sets of double stranded DNA. Of course the process is a little more complicated than that with one strand needing to be flipped for the enzymes to work properly.