There are 25 million to a billion different T-cells in your body. Each cell has a unique T-cell receptor that can fit with only one kind of antigen, like a lock that can fit with only one shape of key. Antigens and receptors work a lot like a lock and key. Each of the 25 million to a billion different T-cells fit with a different shape of antigen.
Motivating operation. Motivating operation (MO) is a behavioristic concept introduced by Jack Michael in 1982. It is used to explain variations in the effects in the consequences of behavior. Most importantly, a MO affects how strongly the person is reinforced or punished by the consequences of their behavior.
Photo by: Gabi Moisa. Reinforcement theory is the process of shaping behavior by controlling the consequences of the behavior. In reinforcement theory a combination of rewards and/or punishments is used to reinforce desired behavior or extinguish unwanted behavior. Any behavior that elicits a consequence is called operant behavior, because the individual operates on his or her environment. Reinforcement theory concentrates on the relationship between the operant behavior and the associated consequences, and is sometimes referred to as operant conditioning.