 movements across cell membranes exocytosis, first the contents, definition of exocytosis, role of exocytosis in cell secretions, role of exocytosis in removal of waste, and role of exocytosis in membrane replacements, first the definition, so exocytosis is the process in which the material present within cell they are packed into a vesicle and then transported out of cell, students if we define it in a simple way, how is the process of exocytosis that the molecules which have to be sent out of the cell, they are packed into a vesicle form and then brought into cell membrane so that they can be moved out or transported from there, exocytosis, if we look at exocytosis in the context of endocytosis, in endocytosis the material from the cell membrane is packed into the cell, when in exocytosis the material is sent out of the cell, now these different types of materials which are released through exocytosis are released, you can divide them into two major categories, one is the category which is called cell secretions, cell secretions means that the useful substances which are made into the cell and then taken out of the cell to transport to another place, like enzymes, now the enzyme will be made into the cell but it has to be taken out of the work cell, so in this case the enzymes, the different types of protein, the enzymes are packed into a vesicle form, now the enzymes of the molecule are made into the final form, so the final form comes into the Golgi practice of molecules, from there they will be packed into a vesicle form and sent to the cell membrane, when it reaches to the vesicle cell membrane, it will become a part of the vesicle cell membrane when the material from the cell will be transported out, similarly the neurotransmitters are the neurotransmitters, the neurotransmitters tell you that there are special secretions which are released by the neurons, so the neurotransmitters release their neurotransmitters on the axons ending, so the neurotransmitters in the cell body of the neuron become a neurotransmitter, from there it will be packed into a vesicle form, it will be brought to the axons and after reaching the axons it will be released from the cells, so the neurotransmitters are the same, another useful substance example is the proteins which have to be a part of the cell membrane, all the proteins are sent to the cytoplasm in the ribosome synthesizer, whether it is synthesized in cytoplasm or whether it is synthesized on the endoplasmic reticulum, the protein which has to go out of the cell is always synthesized on the endoplasmic reticulum, after being synthesized on the endoplasmic reticulum it will be packed into a vesicle form, it will be sent to the golgiopratus, then the golgiopratus will modify it further and it will be sent out of the cell, it will be taken to the cell membrane so this is the material transport, this is the useful substance of the exocytosis so the waste materials, if we look at this diagram, this is a vesicle which is formed in the cell, this vesicle is basically made, if we take the final form then the vesicles are usually cut off from the golgiopratus, different types of proteins can be found in vesicles, some other useful substances can be found, vesicle after being cut off from the golgiopratus, the cell membrane will be taken, after being cut off from the golgiopratus, the vesicle will merge with the cell membrane, what will happen to the mergers, the mergers will become a part of it, so as soon as the vesicle becomes a part of the cell membrane, the vesicle membrane will be attached to the cell membrane and it will become a part of it, when the material pack will be transported out of the cell, removal of waste, through the exocytosis of the cell membrane in transport, the second important work is to send the waste material out of the cell now those are the substances like unicellular exocytosis for example, amoeba takes its food through endocytosis, the digestions of the food and the useful substances are absorbed, now the waste materials are to be sent out of the cell and the process of sending the waste material out of the cell will be the exocytosis if we look at this diagram, from the start point, the food particle is brought through endocytosis through the cell, after that it is digested, after that the useful substances are absorbed, when the waste material is taken out of the cell through exocytosis, so the process of taking out the waste material from the cell is actually the exocytosis, through exocytosis useful substances are also taken out of the cell and waste substances are also taken out of the cell one important benefit of exocytosis is the cell membrane, now in the cell membrane, the specific surface area of the cell membrane, when the cell endocytosis is done, some part of the cell membrane comes inside the cell when the endocytosis is done, the result is that the surface area of the cell membrane is done, now what will the exocytosis do? take the membrane out of the cell, it will go to the cell membrane in the exocytosis, the membrane vesicles will be part of the cell membrane so the size of the vesicle will be increased in the cell membrane so the size of the vesicle will be increased in the cell membrane so the size of the vesicle will be increased in the cell membrane so we can say that through endocytosis, the cell membranes are cut off and come inside, when through exocytosis, the cell membranes are part of the membrane structure because of exocytosis, the surface area of the cell membrane increases and the endocytosis loses