Question

Sodium ions, oxygen (O2), and glucose pass directly through lipid bilayers at dramatically different rates. Which of the following choices presents the correct order, from fastest to slowest?A. Glucose, oxygen, sodium ions.
B. Glucose, sodium ions, oxygen.
C. Oxygen, glucose, sodium ions.
D. Oxygen, sodium ions, glucose.
E. Sodium ions, glucose, oxygen.
F. Sodium ions, oxygen, glucose.

Answer 1

Answer:

The correct order, from fastest to slowest, for the passage of molecules and ions through the cell membrane is oxygen, sodium ions, glucose (option D).

Explanation:

The plasma membrane is a lipid bilayer, with glycoproteins and membrane proteins, which constitutes a semi-permeable barrier to the passage of substances into and out of the cell.

The speed with which a substance can pass through the membrane depends on its chemical properties -hydrophilic substances pass through with greater difficulty than lipophilic ones- requiring in some cases specialized transport mechanisms. The different rates with which a substance passes depends on this.

• Oxygen (O₂) passes through simple diffusion, depending on a concentration gradient. It's the molecule that passes through the membrane the fastest.
• In second place, there would be the Na⁺ ions -charged atoms- that cross the membrane by facilitated diffusion, through specific ionic channels.
• The glucose molecule, being larger, requires the use of transport proteins, being its passage through the membrane slower with respect to oxygen or sodium.

Undoubtedly, molecular weight and affinity for the plasma membrane are determining factors for the passage of molecules through the lipid bilayer.

Learn more:

Simple diffusion and active transport  brainly.com/question/6420224