All living things use molecules to sense. Amoebas use sensing receptors on their outer membrane to find food, and dogs have receptor molecules on the inside of their nose to identify other animals and recognize territories. Receptor molecules only interact with molecules that fit into its shape, like puzzle pieces fitting together. At this exhibit molecules and receptor sites are represented as a puzzle. Visitors are challenged to fit a molecule into the appropriate receptor molecule. When a molecule interacts with a sensing receptor molecule a signal is sent to your brain. Your brain receives the information and distinguishes and identifies it.
All living things, from simple to highly complex organisms, sense their environment. Visitors choose one of four organisms and step through a series of magnifications to see the interaction between molecules in the environment and the receptor molecules on their bodies. Moths use their antennae that are covered with receptor molecules to find female moths from far away. Amoeba , a one-celled organism, has a membrane (skin) around its body that has receptor molecules in it that senses food molecules. Humans can recognize about 10,000 different odors, many associated with food. Receptor sites for odor molecules are also found inside the noses of dogs. Dogs can smell ten times better than humans because a dog's nose has ten times more odor receptor molecules than humans do. By looking at all four organisms, visitors see that all these organisms have the same sensing-and-receptor molecular interaction.
Your nose knows, but can your hand tell the difference between different odor molecules? Visitors attempt to identify two odor molecules using their hands rather than their nose. While looking at the models of the molecules on display, the visitor reaches inside a box and feels one of the same molecules. The only way an odor can be detected is if some of its molecules are floating in the air and go up your nose. Different odor molecules have different shapes that fit into different receptors inside our nose. If a molecule does not fit into any of the receptor sites the odor will not be smelled. Most smells are actually a mixture of many different odor molecules. Each bottle at this exhibit only contains one kind of odor molecule to show what it smells like on its own. The molecule in the bottle is the most abundant molecule in the odor of each example. When you smell a real banana or apple, the odor molecule in the bottle combines with other odor molecules. Hence, the real thing smells a little different from the sample in the bottle.