Part B - Permeability of the lipid bilayer Some solutes are able to pass directly through the lipid bilayer of a plasma membrane, whereas other solutes require a transport protein or other mechanism to cross between the inside and the outside of a cell. The fact that the plasma membrane is permeable to some solutes but not others is what is referred to as selective permeability. Which of the following molecules can cross the lipid bilayer of a membrane directly, without a transport protein or other mechanism

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Complete Question:

Part B - Permeability of the lipid bilayer Some solutes are able to pass directly through the lipid bilayer of a plasma membrane, whereas other solutes require a transport protein or other mechanism to cross between the inside and the outside of a cell. The fact that the plasma membrane is permeable to some solutes but not others is what is referred to as selective permeability. Which of the following molecules can cross the lipid bilayer of a membrane directly, without a transport protein or other mechanism?

a) proteins

b) water

c) ions

d) sucrose

e) lipids

f) carbon dioxide

g) oxygen

Answer:

b) water

e) lipids

f) carbon dioxide

g) oxygen

Explanation:

Diffusion is the means by which molecules like water, lipids, carbon dioxide and oxygen easily move across the lipid bilayer of a membrane directly without the use of a transport protein or any another mechanism.

Diffusion is the way or means through which molecules (such as gases or liquids) move across a membrane from and region of higher concentration to a region of lower concentration.

Before a molecule can pass through the semi permeable membrane without the use of any mechanism or transport protein, it has to be:

a) a small molecule

b) an uncharged molecule

c) an hydrophobic molecule