PSIO 303 BLOCK 2 L6 EXAM PRACTICE
TEST WITH COMPLETE SOLUTIONS
List and discuss the diagnostic characteristics of passive diffusion. -
Answer✔️✔️-ALL channels, and SOME carriers, can only support
NET transport DOWN the electrochemical gradient of their
transported substrates
One category of carrier can do something no channel can
Support net movement of their substrates AGAINST and
electrochemical gradient
List and discuss the diagnostic characteristics of carrier mediated
transport - Answer✔️✔️-Saturability
At low concentrations, transport increases in almost direct
proportion in increases in [S]
First-order function
As [S] continues to increase, the rate of transport begins to
approach a maximum value
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At high enough substrate concentrations, the carrier-mediated
process can be expected to 'saturate'
In the context of cellular physiology, describe the importance of the
kinetic parameters J max and K t - Answer✔️✔️-J max = maximal
rate of a carrier-mediated transport system, product of the number
of transporters x the
turnover number
K t = equal to the substrate concentration that produces 'half-
maximal' transport when the rate of transport is
equal to J max /2)
Given either a Michaelis-Menton plot or an Eadie-Hofstee plot,
deduce Jmax and Kt - Answer✔️✔️-Michaelis-Menton equation:
relationship between substrate concentration and the rate of
transport (revealing
the saturation of that rate) is generally described by the following
equation:
J = rate of transport at a substrate concentration equal to (S)
J max = maximal rate of transport and reflects 'saturation' of the
process.
Given either a Michaelis-Menten plot or an Eadie-Hofstee plot,
deduce Jmax and Kt. Given a substrate concentration, a Jmax, and
a Kt, use the Michaelis-Menten equation to calculate the rate of
carrier-mediated transport. - Answer✔️✔️-J=Jmax[S]/Kt+[S]
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