Question

FACILITATED DIFFUSION: Sort the phrases into the appropriate bins depending on whether they are true only for channels, true only for carrier proteins, or true for both channels and carriers.

a. provide a continuous path across the membrane

b. transport primarily small polar organic molecules

c. provide hydrophilic path across the membrane

d. are integral membrane proteins

e. transport solutes down a concentration or electrochemical gradient

f. undergo a change in shape to transport solutes across the membrane

g. allow water molecules and small ions to flow quickly across the membrane

 

Answer 1

The substances are transported across the cell membrane to keep the cells alive. There are two types of membrane transport proteins, which include carrier proteins and channel proteins.

 

The integral proteins that extend into the lipid bilayer of the plasma membrane and service channels for water-soluble substances are called carrier proteins. The water-soluble substances include glucose and electrolytes. During transportation, the carrier proteins bind to the solute on one side and undergo a conformational change and release from another side—for example, GLUT1 glucose carrier protein, etc.

 

The ion-selective proteins and contain pores through which solutes pass when they are open at high flux rates are called channel proteins. For example, calcium ( \(\mathrm{Ca}^{2+}\) ) channel proteins, sodium (Na^*) channel protein, etc.

a) Allow water molecules and small ions to flow quickly across the membrane- only channels.

b) Transport primarily small polar organic molecules- only carriers.

c) Are integral membrane proteins- both channels and campers.

d) Provide a continuous path across the membrane- only channels.

e) Transport solutes down a concentration or electrochemical gradient- both channels and carriers.

f) Provide a hydrophilic path across the membrane- both channels and carriers.

g) Change shape to transport solute across the membrane- only carriers.