Correct option is A
A phospholipid bilayer, which forms the core structure of cell membranes, is a hydrophobic structure that allows the passage of small, non-polar molecules and some small polar molecules that are lipophilic (fat-soluble).
CO₂ (carbon dioxide) is a non-polar molecule and can diffuse easily across the bilayer.
Diethyl urea is a small polar molecule, but due to its low polarity and small size, it can pass through the hydrophobic core of the phospholipid bilayer, though with slower diffusion compared to non-polar molecules.
Information Booster:
CO₂ is a non-polar molecule and easily crosses the phospholipid bilayer through simple diffusion.
Diethyl urea, despite being polar, is small enough to cross the hydrophobic core of the membrane, making it permeable, although less so than CO₂.
Phospholipid bilayers are semipermeable and allow small, non-polar molecules to pass through more readily, while polar and charged molecules require transport mechanisms.
Molecules like water and glucose are polar and typically require specialized transport proteins to cross the membrane effectively.
Lysine, an amino acid, is highly charged and would have difficulty crossing the bilayer without the assistance of transporters.
Ethanol, while small and polar, can pass through the bilayer due to its amphipathic nature, but it does so less efficiently compared to non-polar molecules.
Urea is small and polar, and while it can cross the bilayer to some extent, it still has some difficulty due to its polarity.
Chloride ions are highly charged and cannot diffuse through the hydrophobic core of the membrane without transport proteins.
Additional Information:
(b) Water and Glucose: Water can pass through the bilayer, but glucose is too large and polar to diffuse through unaided.
(c) Lysine and Ethanol: Lysine is too charged to pass easily, and ethanol, though small and polar, can diffuse, but less easily than non-polar molecules like CO₂.
(d) Urea and Chloride ions: Both are polar and charged, making it difficult for them to pass through the bilayer without the aid of specific transporters.
