the free energy of the reactants is greater than that of the products. induced-fit model. A model of enzyme-catalyzed reactions in which the enzyme changes shape when substrates bind to the active site; this change in shape is called an induced fit. lock-and-key model A model of enzyme-catalyzed reactions in which the enzyme is a rigid lock and the substrates are the keys that fit into the lock and then react.
System administrator. For the privileged user account, see Superuser. A system administrator, or sysadmin, is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems; especially multi-user computers, such as servers.
Accounts are not simply magically created from scratch or because the computer knew that you needed one. Instead, someone needs to enter in information about you so that your account can be created. This is generally a system administrator for the Web site. This is only one tiny part of what Web administration entails. In fact, creating user accounts is usually automated and the sysadmin only looks at them when something breaks rather than for every individual account.