Question

Which of the following factors does not affect membrane permeability? View Available Hint(s) Which of the following factors does not affect membrane permeability? The amount of cholesterol in the membrane The saturation of hydrocarbon tails in membrane phospholipids The polarity of membrane phospholipids Temperature

Answer 1

The polarity of membrane phospholipids does not affect membrane permeability. Temperature, the saturation of fatty acids in phospholipids, and cholesterol content are factors that do influence membrane permeability.

Step-by-step explanation:

The permeability of cellular membranes is influenced by several factors; however, the polarity of membrane phospholipids does not directly affect membrane permeability. Factors that do impact permeability include temperature, as increased temperature generally increases the fluidity of the membrane, allowing for more movement within the membrane itself. The saturation of the hydrocarbon tails in membrane phospholipids also plays a critical role. Saturated fats with straight tails pack together more tightly than unsaturated fats with kinked tails, making the membrane less permeable. Additionally, cholesterol content affects permeability by filling the spaces between fatty acid tails, reducing mobility and thus decreasing permeability to certain ions and molecules.

Answer 2

The polarity of membrane phospholipids

Step-by-step explanation:

The inner core of membranes is made of nonpolar tails of phospholipids which in turn makes the membranes impermeable for polar, large and charged substances since these substances cannot cross the non-polar inner core. The saturated hydrocarbon tails pack tightly and make membrane less permeable while cholesterol affects the membrane permeability by interacting with non-polar tails.

Higher temperatures make the membrane more fluid and more permeable while at lower temperatures, membranes are more rigid due to tight packing of hydrocarbon tails and less permeable. The polar heads of phospholipids make the inner and outer surface of the membrane. Therefore, the polarity of phospholipids does not affect the membrane permeability.