Fungi join bacteria as the primary decomposers in different ecosystems. They feed on the organic remains of dead plants. They release special enzymes that break down lignin, a structurally complex substance in wood. Decomposing organic matter is considered by ecologists as the major ecological role of fungi.
The nervous system communicates through electrical impulses and the communication is very fast. It works in a relay fashion, from point to point comparable to the way the old telephones systems used to work.
The endocrine system communicates by chemical signals via the bloodstream. Hormones are secreted into the blood and extra cellular fluids, then transported to target cells, which must bear a receptor to be able to bind to a specific hormone, and respond.
Hormones are chemical messengers secreted into blood or extracellular fluid that affect the function of other cells.
Endocrine communication is not quite as fast as the nervous system communication
The lock an key analogy is used because each enzyme has specific substrates that fit into it. This is like how locks only work with a specific key. The enzyme is the lock and the substrates are the key.
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This analogy is not perfect because there are often multiple substrates for each enzyme reaction. It only takes one key to turn the lock. The reaction is also taking place between the substrates themselves and not the enzyme. In the lock and key analogy, the lock is affected by the key, but in an enzyme reaction, the substrates are affected by the enzyme.
Hope I’ve helped ;)
reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population.