Explain Why Cells Are The Building Blocks Of Tissues And Therefore Multicellular Organisms

“Cells are the building blocks of tissues and therefore multicellular organisms. Using specific examples, describe some of the mechanisms used by cells to provide organisation within tissues containing different cell types.”

One cannot adequately contemplate the organisation of tissues, let alone organisms. Words fall short when explaining the sheer vastness of their complexity. It is incredible that such astonishingly patterned structures can be formed from so many individual cells but greater still, all this arises from a single fertilized egg. All of the cells that make up an organism contain the same genome but are specialized in different ways. These varies cell types require mechanisms so that organisation is maintained within tissues.
With respect to cells this is known as cell signalling. Information exists in different forms. When you receive a phone call for example, radio waves are converted by your mobile to sound waves. This is known as signal transduction and cells communicate in a similar manner. Cell communication can usually work both ways, however the cell sending a signal molecule is known as the signalling cell and its message is detected by the target cell. Signal transduction comes into play when a receptor protein within the target cell converts the incoming extracellular signal into an intracellular signal which the cell can understand, thus altering its behaviour based on the message.
Signal molecules can be nucleotides, steroids, proteins, peptides, eicosanoids, amino acids or even dissolved gases – but the styles of communication are quite similar. Cell communication types can range from very local signalling such as contact-dependent cell-cell communication to organism-wide communication as is the case with endocrine