Question

How do hormones differ from enzymes and neurotransmitters?

Answer 1

Hint: Our body synthesizes and makes use of various molecules. These molecules make sure that the cells in our body can communicate with each other, catalyze various chemical reactions in the body, perform cellular functions, and grow. Hormones, enzymes, and neurotransmitters are the chemical molecules that influence the cells to perform one or more functions.

Complete answer:
-Hormones are signalling molecules secreted by plants and animals. They influence the target cell to perform certain cellular functions (such as growth). They may also affect the behaviour of the target cell and in turn the behaviour of the organism. They also help maintain homeostasis. In humans, the endocrine gland secretes hormones directly into the bloodstream. This is called endocrine signalling. The hormone can travel longer distances because it is secreted into the blood. Hormones can be eicosanoids, lipids, or amino acids/peptides/proteins.
-Enzymes are a reaction catalyst. They have an active site to which a substrate will go and bind. This binding is very specific. The enzyme acts on the substrate but remains unaltered itself. The enzymes either break down a substrate or help in the synthesis of a product. The enzymes also influence the rate of a chemical reaction. Enzymes are composed of proteins.
-Neurotransmitters are also signally molecules. They help neurons communicate with each other, with muscle cells, or a gland cell. Neurotransmitters are packaged within the synaptic vesicles, found at the terminal end of the neuron. The nerve impulse (electrical signal) travels through the neuron. As the impulse reaches the terminal end, the synaptic vesicles fuse with the neuron membrane and release the neurotransmitter. The neurotransmitter is received by the neighbouring neuron. Neurotransmitters are made up of proteins.

Note: In the case of hormones, they need not be released into the blood every time. If the cells are nearby the hormones may directly travel to the neighbouring cell. This is called paracrine signalling. In some cases, the cell releases hormones that bind to the same cell. This brings about changes in the cell. This is known as autocrine signalling.