Most of the cell surface receptors and glycoproteins. These glycoproteins have active sites that recognize specific signals, like hormones, that initiate secondary signaling pathways inside of the cell, in response to the external signal. This is how cells respond to environmental stimuli.
If a change in glycoproteins makes them unable to bind signaling molecules (like hormones) or makes them permanently bind these molecules, there will definitely be a defect in how the cell responds to external stimuli. The cell will be, for example, be unable to respond to insulin in case of elevated blood sugar levels as is the case with diabetics.
The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. The water table is the surface where the water pressure head is equal to the atmospheric pressure.
