The different ways in which organisms use ATP

lot more reactive; as a result, the reaction of splitting the glucose molecule into triose phosphate has a lower activation energy than before. Similarly, during the Calvin cycle in the light independent stage of photosynthesis, ATP produced from the previous light dependent stage is used to help convert a GP molecule into a TP molecule. ATP is also very important in the synthesis of macromolecules from their basic units. This is because energy is required to form bonds that link monomers together to produce a polymer, such as peptide bonds in connecting amino acids to form polypeptide chains which will ultimately become a protein. This is apparent in the transmission of impulses across synapse – all pre-synaptic knobs have large number of mitochondria to produce large amount of ATP. This is because neurotransmitters such as acetylcholine after they have stimulated protein channels on the post-synaptic membrane are promptly broken down by enzymes into their component molecules – ethanoic acid and choline. These then have to be recycled in the pre-synaptic knob to reform acetylcholine which requires ATP, to ensure that transmission of impulses across the synapse can continue.ATP plays a very important role in the transport of molecules across membranes as it provides the energy for active transport. In order to transport molecules against their concentration gradient, there are specific transport proteins in the cell membrane which the molecules can bind to, when these proteins are activated by an ATP, they changes shape and as a result, transport the molecule across the membrane. This process is essential to many activities such as the transport of water in plants – the soil has a greater water potential than root hair cells, as a result, the root hair cells has to actively transport ions into the cells which lowers the water potential within, so water naturally diffuses in down the water potential gradient. ATP is also required in maintaining a resting potential across neurone membranes, to prepare for the transmission of an action potential – the sodium/potassium pump actively transports three sodium ion out of the neurone for two potassium ion in, so there is more positively charged ions outside of the neurone compared to within, this immediately creating a potential difference across the membranes. Most of the energy used in mobile organisms is for movement, this is because muscle contraction requires large amount of energy and therefore ATP. ATP is very important to the sliding filaments mechanism as it provides the energy to detach the myosin heads from the actin filaments and return the heads to their original angle, so that the myosin heads are ready to attach to another binding site further along the actin filament and flex their heads in unison to pull the actin filament along. ATP is also required in secretion as it form the lysosomes necessary for secretion of cell products such as enzymes. This is very important in phagocytosis – one of the main immune responses where a white blood cell engulfs the pathogen within a phagocytic vacuole in the cytoplasm, a lysosome then fuses with it so the lysosomal enzymes contained within breaks down the pathogen and destroys it. ATP provides an immediate source of energy for many processes vital for life; as a result, they play an important role in all aspect of living organisms’ lives and without which, there would probably be no life on Earth.