the visual sensory cells in the retina of the eye continuously release the neurotransmitter glutamate in the dark. It is assumed that the neurotransmitter release is temporally and locally constant everywhere on the presynaptic membrane and that the glutamate concentration on the presynaptic membrane surface is $1$mM$.($see description of synapse structure in figure $1)$ a$)$ suppose that glutamate binds to receptors on the postsynaptic membrane and is transported into the postsynaptic cell so that the glutamate concentration remains constant at $0\mathrm{.}3$mM on the surface of the postsynaptic membrane. What is the glutamate flux $($molecule$/$m$^2$s$)$ through the synaptic gap when the distance between the pre$-$ and postsynaptic membrane is $50$nm$?$ The diffusion coefficient at body temperature is $37$C D$=7\mathrm{.}6*10^-6$ cm$^2$s$^-1$ and you can assume the synaptic gap to be water. b$)$ Now the temperature of the head is $20$C during surgery. The viscosity of water at $37$C is $0\mathrm{.}688$ mPas and at $20$ it is $1\mathrm{.}002$ mPas. How much glutamate flux decreases with this decrease in head temperature. Assume glutamate concentrations remain unchanged.