cell membrane structure
Cell Membrane Structure
Phospholipids are arranged in to layers, called the bilayer. They only have 2 fatty acids, this is because the third fatty acid is replaced by a negatively charged phosphate group. The phosphate heads are polar, in other words attracted to water, therefore they are hydrophilic. The lipid tails are non-popular as they’re not attracted to water and therefore known as hydrophobic. When phospholipids are added to the water, they rearrange themselves so that the hydrophilic heads touch the surface of the water, and the hydrophobic tails are kept away. The most stable arrangement that the cell surface membrane phospholipid gets into is the bilayer as it avoids the hydrophobic tails having any contact with the aqueous solution.
Membranes contain phospholipids, proteins and carbohydrates, which are arranged in a fluid mosaic structure. The proteins within the membrane are responsible for most of the membranes’ properties. For example, on the inside surface of cell membranes, proteins are attached, involved in maintaining the cell’s shape. These could be enzymes too. Proteins on the outside surface of cell membranes can act as receptors, such as antigens or hormones.
Carbohydrates are found on the outside of the surface, they can be attached to the proteins or phospholipids. The proteins with carbohydrates attached are known as glycoproteins whereas the phospholipids with carbohydrates attached are called glycolipids.
One type of evidence to prove the structure of the cell membrane is the mouse and human cell fusion experiment. The two types of cells were labelled in different fluorescent dyes. Once the cells fused, they were left for an hour in a temperature of 37oc, the approximate body temperature for mammals. From this, they saw that the cells had joined together showing that there is fluid within the cells for them to move.
Phospholipids are arranged in to layers, called the bilayer. They only have 2 fatty acids, this is because the third fatty acid is replaced by a negatively charged phosphate group. The phosphate heads are polar, in other words attracted to water, therefore they are hydrophilic. The lipid tails are non-popular as they’re not attracted to water and therefore known as hydrophobic. When phospholipids are added to the water, they rearrange themselves so that the hydrophilic heads touch the surface of the water, and the hydrophobic tails are kept away. The most stable arrangement that the cell surface membrane phospholipid gets into is the bilayer as it avoids the hydrophobic tails having any contact with the aqueous solution.
Membranes contain phospholipids, proteins and carbohydrates, which are arranged in a fluid mosaic structure. The proteins within the membrane are responsible for most of the membranes’ properties. For example, on the inside surface of cell membranes, proteins are attached, involved in maintaining the cell’s shape. These could be enzymes too. Proteins on the outside surface of cell membranes can act as receptors, such as antigens or hormones.
Carbohydrates are found on the outside of the surface, they can be attached to the proteins or phospholipids. The proteins with carbohydrates attached are known as glycoproteins whereas the phospholipids with carbohydrates attached are called glycolipids.
One type of evidence to prove the structure of the cell membrane is the mouse and human cell fusion experiment. The two types of cells were labelled in different fluorescent dyes. Once the cells fused, they were left for an hour in a temperature of 37oc, the approximate body temperature for mammals. From this, they saw that the cells had joined together showing that there is fluid within the cells for them to move.