Question

Explain how the "self-sealing" bubble membrane helps to illustrate the passage of molecules through a cell membrane and the property of selective permeability.

Answer 1

Given its selective permeability, the cell membrane controls the entry and exit of substances, simulating a 'self-sealing' bubble membrane that allows certain molecules to pass while excluding others.

Step-by-step explanation:

Understanding Selective Permeability of Cell Membranes

The selective permeability of a cell membrane is a crucial feature that allows a cell to maintain homeostasis. The membrane's lipid bilayer acts as a self-sealing barrier that determines which molecules can freely pass through and which cannot. Small nonpolar molecules, such as oxygen and carbon dioxide, can move through the lipid bilayer due to their compatibility with the hydrophobic interior.

Passive transport is a process that enables molecules to cross the membrane without the need for cellular energy. This includes diffusion, osmosis, and facilitated diffusion. These methods regulate the movement of ions and small molecules, ensuring that a cell's internal environment remains balanced.

To simulate a cell membrane's selective permeability, one might imagine a "self-sealing" bubble membrane that can automatically close around certain molecules while excluding others, based on size, charge, or solubility criteria—just as a cell membrane does in reality.

Answer 2

The "self-sealing" bubble membrane is a model used to illustrate the passage of molecules through a cell membrane and the property of selective permeability by soap bubble stretched over the opening of a glass tube. The bubble represents the cell membrane, while the glass tube represents the channel or pore in the membrane.

Step-by-step explanation:

To understand how this model works, let's imagine that the soap bubble represents a cell membrane and a dye molecule represents a substance trying to pass through the membrane. If the dye molecule is smaller than the pore size of the self-sealing bubble membrane, it can easily pass through by diffusing from an area of high concentration to an area of low concentration. This process is called passive transport.

The self-sealing bubble membrane also illustrates the property of selective permeability. Only small molecules that can fit through the pores of the membrane can pass through, while larger molecules are unable to. This is similar to how the cell membrane selectively allows certain substances to enter or leave the cell.

So therefore the "self-sealing" bubble membrane is a model used to illustrate the passage of molecules through a cell membrane and the property of selective permeability. This model consists of a soap bubble stretched over the opening of a glass tube. The bubble represents the cell membrane, while the glass tube represents the channel or pore in the membrane.