Examine the experimental chamber in Figure 6.8a. Explain what would occur by osmosis if you added a 1-M solution of sodium chloride on the left side and an equal volume of a 1.5 M solution of potassium ions on the right. How might the addition of the CFTR protein to the lipid bilayer impact the direction of water movement?

Verified step by step guidance

1. Identify the concentration gradient: The left side has a 1 M NaCl solution, and the right side has a 1.5 M K+ solution. This creates a concentration gradient across the lipid bilayer.
2. Understand osmosis: Water will move from the side with lower solute concentration (left side) to the side with higher solute concentration (right side) to balance the solute concentrations.
3. Consider the role of CFTR protein: CFTR is a chloride channel that can facilitate the movement of Cl- ions across the membrane, potentially affecting the osmotic balance.
4. Predict the impact of CFTR: If CFTR is added, Cl- ions may move from the left to the right side, potentially increasing the osmotic gradient and influencing water movement.
5. Conclude the direction of water movement: With CFTR, water movement might be enhanced towards the right side due to increased solute concentration from Cl- ion movement.

Key Concepts

Osmosis

Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. In the context of the question, adding a 1-M sodium chloride solution on one side and a 1.5 M potassium ion solution on the other creates a concentration gradient. Water will move towards the higher concentration of solutes (potassium ions) to balance the solute concentrations on both sides.

Lipid Bilayer

A lipid bilayer is a fundamental component of cell membranes, consisting of two layers of phospholipids with hydrophilic heads facing outward and hydrophobic tails facing inward. In the experimental chamber, the lipid bilayer separates the two solutions, allowing for selective permeability. This structure is crucial for understanding how substances, including water and ions, can move across the membrane during osmosis and other transport processes.

CFTR Protein

The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein is a channel protein that facilitates the transport of chloride ions across epithelial cell membranes. In the context of the question, the addition of CFTR to the lipid bilayer could enhance the movement of chloride ions, potentially altering osmotic balance and influencing the direction of water movement. This could lead to changes in the osmotic gradient, affecting how water flows between the two compartments.