Question

select all that apply
choose all the substances that leave the blood by diffusing directly through the plasma membrane of endothelial cells?

• steroid hormones
• carbon dioxide
• glucose
• large proteins
• oxygen
• electrolytes

Explanation:

To determine which substances diffuse directly through the plasma membrane of endothelial cells, we analyze their properties:

• Steroid hormones: Lipid - soluble, so they can pass through the lipid - bilayer of the plasma membrane by simple diffusion.
• Carbon dioxide: A small, non - polar molecule. It can diffuse directly through the plasma membrane as it can pass through the lipid - bilayer.
• Oxygen: A small, non - polar molecule. Similar to carbon dioxide, it can diffuse directly through the plasma membrane.
• Glucose: It is a polar molecule and is transported across the membrane via facilitated diffusion (using transporters), not simple diffusion through the lipid - bilayer.
• Large proteins: They are too large and polar to diffuse directly through the plasma membrane. They may be transported via vesicular transport or other specialized mechanisms.
• Electrolytes: They are charged (ions) and cannot diffuse directly through the non - polar lipid - bilayer of the plasma membrane. They require ion channels or transporters for movement.

Answer:

A. Steroid hormones, B. Carbon dioxide, E. Oxygen