Question

multiple choice question
compare the two archaeal membranes illustrated here. which of the following statements is false?

• membrane b is likely to be found in an extreme thermophile.
• membrane a has greater rigidity.
• membrane b is composed of diglycerol tetraether lipids.
• membrane a is composed of glycerol diether lipids.

Explanation:

1. Recall archaeal membrane structure: Membrane A is a bilayer (glycerol diether lipids), Membrane B is a monolayer (diglycerol tetraether lipids, more rigid, common in extreme thermophiles as it's more stable at high temps).
2. Analyze each option:

• "Membrane B is likely to be found in an extreme thermophile": True, as monolayer (tetraether) is stable at high temps.
• "Membrane A has greater rigidity": False. Monolayer (B) is more rigid than bilayer (A) because the tetraether linkage and monolayer structure provide more stability.
• "Membrane B is composed of diglycerol tetraether lipids": True, as B is a monolayer typical of diglycerol tetraether.
• "Membrane A is composed of glycerol diether lipids": True, as A is a bilayer typical of glycerol diether.

Answer:

B. Membrane A has greater rigidity