Final answer:
Closing ion channels in a cell membrane results in a decrease or cessation of ion diffusion, altering the typical J versus C1-C2 graph by producing a flatter slope, which indicates minimal or no net ion movement.
Step-by-step explanation:
When discussing the J versus C1-C2 graph in the context of channel diffusion, we are likely referring to the flux of ions across a cell membrane through ion channels. If you close these channels, there will be a decrease in the diffusion or movement of ions from one side of the membrane to the other. In a normal state, ion channels allow ions to move in accordance with the concentration gradient, as depicted in the provided figures.
The closing of ion channels, which are pathways for the facilitated diffusion of ions like Na+ and K+, will result in a change on the graph showing ion movement (J) versus the concentration difference between two regions (C1-C2). Normally, there's a high initial rate of ion movement from a region of high concentration (C1) to a region of low concentration (C2), shown as a steep slope on the graph. However, with ion channels closed, this rate is drastically reduced or potentially halted, leading to a flatter slope indicating minimal or no net ion movement across the membrane.
The concept is akin to the observable spread of food coloring in water, which moves from high to low concentration until it is evenly distributed (free diffusion). But in cells, ion channels regulate this process, and when these channels are absent or closed, diffusion is impeded, changing the typical diffusion dynamics illustrated in the J versus C1-C2 graph.