Our current paradigm of insulin resistance is that of a lock and key, and it’s simply wrong.
Insulin is a hormone that acts upon a hormonal receptor on a cell surface in order to have an effect. This is often referred to as lock and key model.
The lock is the insulin receptor which keeps the gates to the cell closed. When the proper key (insulin) is inserted, then the gate opens to let glucose from the blood inside the cell. This glucose is then able to power the cell machinery.
Once you remove the key (insulin) then the gate closes back up and glucose in the blood is no longer able to go inside the cell.