Question

What do protein channels serve as in the cell membrane?

Answer 1

Protein channels in the cell membrane are passageways that allow specific ions and water molecules to move through the membrane, facilitating important physiological processes like nerve signal transmission and muscle contraction.

Step-by-step explanation:

Protein channels serve as passageways through the cell membrane, which allow molecules, especially ions, to move across it. These channels are critical for maintaining the proper ionic balance within and outside the cell, which is essential for various physiological processes. For instance, aquaporins are a specific type of channel proteins that facilitate the rapid transport of water molecules. On the other hand, ion channels such as sodium, potassium, and calcium channels are essential for processes such as electrical signal transmission in nerve cells and muscle contraction.

These protein channels are highly specific and can recognize and transport particular ions based on the interaction between the ion charge and the amino acid side chains within the channel. Channels embedded within the cell membrane consist of hydrophobic and hydrophilic domains that correspond to the hydrophobic core of the membrane and the aqueous environments respectively, allowing the protein to span across the membrane while providing a hydrophilic pathway for ion transport.

Answer 2

Protein channels, also known as ion channels, serve as selective passageways in the cell membrane, allowing the movement of specific molecules and ions between the cell's external and internal environments.

Step-by-step explanation:

Channel proteins, also known as ion channels, serve as pores or tiny holes in the cell membrane that allow the passage of specific molecules, such as water molecules and small ions. These proteins play a crucial role in facilitating the movement of ions and other substances across the cell membrane.

For example, water channel proteins called aquaporins enable the rapid diffusion of water molecules across the membrane. Ion channel proteins, on the other hand, facilitate the diffusion of ions, such as sodium and potassium ions, through their hydrophilic channels.

In summary, protein channels serve as selective passageways in the cell membrane, allowing the movement of specific molecules and ions between the cell's external and internal environments.