Lecture 1 - Exam 3

Question 1

What does the Chemiosmotic Theory state?

Answer 1

That the coupling between energy-yielding reactions and energy requiring reactions in the membrane is via ion currents.

Question 2

What is the distinction between primary transport and secondary transport?

Answer 2

Primary transport is driven by an exergonic reaction – proton transport.
Secondary transport is indirectly coupled to primary transport by an energy-yielding chemical reaction by ion currents (proton or sodium gradient)

Question 3

Primary transport reaction

Answer 3

H+in + energy -> H+out

Question 4

Secondary transport reaction

Answer 4

H+out + soluteout -> H+in + solutein

Question 5

The phospholipid bilayer of the bacterial cell membrane acts as?
What does it allow bacteria to maintain?

Answer 5

A barrier that blocks the diffusion of water-soluble molecules into and out of the cell.
It allows bacteria to maintain an internal environment different from the external environment.

Question 6

Metabolites can be maintained at?
anddd what can this promote?

Answer 6

Intracellular concentration that is orders of magnitude higher than extracellular concentrations.
This promotes more rapid enzymatic reactions and allows for retention of metabolic intermediates within the cell.

Question 7

The phospholipid bilayer also minimizes what?

Answer 7

The phospholipid bilayer also minimizes the passive diffusion of ions, including protons, allowing the membrane to maintain electrochemical proton and sodium ion gradients.

Question 8

Electrochemical proton and sodium ion gradients drive what?

Answer 8

These gradients drive ATP synthesis, solute transport, and other membrane activities.

Question 9

Since the phospholipid bilayer is a permeability barrier, anything that is not _______ soluble must enter the cell through? (give examples, too)

Answer 9

Lipid;
They must enter the cell through integral membrane proteins, like transporters, carriers, permeases, and porters.