How drugs can affect the normal functioning of the cell

This assignment explores how drugs (medicines) can affect the normal functioning of the cell. In particular, it looks at how they interact with the cell membrane and the membrane’s structural characteristics relevant to drug interaction.

Cell membranes are made up of a double layer of lipids (fats), with proteins embedded in them. The lipids are arranged in a 'phospholipid bilayer', with their heads pointing outwards and their tails pointing inwards. This structure is fluid, which means that the individual lipid molecules are free to move around within the layer.

The cell membrane is selectively permeable, which means that it allows some substances (such as water and oxygen) to pass through it, but not others (such as large molecules and ions). This is because of the structure of the membrane. The lipid tails are hydrophobic (water-hating), so they form a barrier to anything that is also hydrophobic.

The cell membrane also contains proteins, which can be either integral (spanning the whole width of the membrane) or peripheral (attached to the surface of the membrane). Some of these proteins act as channels, which allow specific molecules to cross the membrane.

Integral proteins can be found in the plasma membrane, which is the outermost layer of the cell. Peripheral proteins are found in other parts of the cell, such as in the cell walls of plants, or in organelles such as mitochondria and chloroplasts.

Cell membranes are also dynamic, which means that they are constantly changing shape. This is due to the movement of the lipid molecules within the membrane.

The fluid mosaic model is a way of describing the structure of cell membranes. It suggests that the cell membrane is like a mosaic, with different types of molecules (lipids, proteins, carbohydrates) arranged in a fluid manner.

The cell membrane has many important functions, including:

- acting as a barrier to keep the contents of the cell together and to prevent substances from entering or leaving the cell without permission

- regulating what goes in and out of the cell

- controlling the movement of materials within the cell

- sending signals between cells

- providing attachment points for enzymes, hormones, and other molecules

Drugs interact with cell membranes in a variety of ways. Some drugs, such as ethanol (alcohol), can dissolve in the lipid layer and so diffuse across the membrane. Other drugs, such as aspirin, are small enough to pass through the membrane channels.

Still others, such as penicillin, bind to specific proteins in the cell membrane and alter their function. And finally, some drugs, such as steroids, can actually change the structure of the cell membrane.

The cell membrane is a vital part of the cell, and so any alteration to its normal functioning can have serious consequences. Drugs that interact with cell membranes can therefore have a wide range of effects on cells, from changing their permeability to altering their signaling functions.

It is important to understand how drugs interact with cell membranes, in order to minimize the risks associated with their use.