Processes in an organism are important as they allow the organism to sustain life. However, if these
processes are not controlled, it could lead to problems which could lower the quality of life of an
organism or if not, it could cause death.
If someone is hyperglycemic, high blood glucose level, the receptors in the pancreas detects this change
and B cells in the islets of langerhans and secrete insulin. Insulin then travels across the body through
the blood and binds to receptors on the liver. This stimulates vesicles, which contains extra carrier
proteins, to bind with the membrane which increases the permeability of glucose as insulin alters the
tertiary structure if the carrier proteins so more glucose can be moved into the cell by facilitated
diffusion. Glucose is then converted into glycogen by glycogenesis. It is important to control to regulate
processes such as maintaining glucose levels because if there were a low amount of insulin produced
then less insulin can bind to the receptors on the liver so less glucose is converted into glycogen.
Therefore there would be more glucose in the body which lowers the water potential in the blood
therefore, water would move from a less negative water potential, in the cells, and move to a more
negative water potential, the blood. This could lead to a high blood pressure which could rapture
important vessels in the body and the cells could shrivel up as there is less water content and water is
important as water is used as a metabolite.
If someone is hypoglycaemic then receptors in the pancreas stimulate alpha cells in the islets of
langerhans to release glucagon. Glucagon then travels across the blood and bind to receptors of the
liver. This then activates the enzyme adenylate cyclase which converts ATP to cAMP. cAMP then
activates another enzyme, protein kinase, which hydrolyses glycogen into glucose and this is known as
glycogenolysis. It is important to regulate processes such as maintaining blood glucose level because if
glucagon levels are too low then less glucagon would bind to receptors in the level which then lead to
less glycogen being hydrolysed into glucose. Glucose is an important molecule for an organism as it is
used in respiration and if less glucose is released then less ATP would be created in respiration and if less
ATP is created then muscle contraction or active transport of molecules may not occur which could
lower the quality of life of organisms or could lead to death of the organism.
In the nervous system, action potentials are created in order to protect the organism from harm, fight or
flight. An incoming potential from the pre synaptic knob causes the calcium ion channels to open which
allows calcium ions to diffuse into the pre synaptic knob. The presence of calcium ions stimulates
enzymes to bind to the vesicle and the vesicle then fuses with the membrane and the neurotransmitter,
acetyl choline (Ach), is then released by exocytosis. Ach then travels across the synaptic cleft and then
binds to receptors on the sodium ion channels on the post synaptic neuron. This causes the sodium ion
channels to open and allows sodium ions to diffuse and depolarise the post synaptic neuron which
causes an action potential when it reaches threshold. Alternatively, an action potential can release
neurotransmitters such as GABA which binds to chloride ion channels on the post synaptic neuron which