Cell Membrane Essay

778 Words 4 Pages
Every living thing is made up of cells. “Cells are small compartments that hold the biological equipment necessary to keep an organism alive and successful.” (“Cells are the Starting Point,” 2016) There are two types of cells called eukaryotic and prokaryotic. In order for the cell to survive, it requires environmental materials to create metabolism and to dispose of waste products within the cell. “All cells have an outer plasma membrane that regulates not only what enters the cell, but also how much of any given substance comes in.” (“Cell Membranes,” 2014) Cell membranes consists of a lipid bilayer which is composed of lipids with hydrophilic and hydrophobic elements. The fluid mosaic model is an example of how the structure of the cell …show more content…
“Phospholipids make up the basic structure of a cell membrane.” (“Cell Membrane: Functions, Role, and Structure,” 2003) It is not a solid. Some of the things the plasma membranes need in order to carry out it’s functions is lipids, proteins, and carbohydrates. They move freely and fluidly in the plane of the membrane. Lipids, made up of glycerol, two fatty acid tails, and a phosphate- linked head group, are used to make a barrier between the cell and its environment. Phospholipids are the main fabric of the membrane. Cholesterol is placed in between the hydrophobic tails of the membrane phospholipids. The proteins are involved in cross-membrane transport and cell communication. Proteins, integral and peripheral, extend pathways to the membrane, cross the membrane entirely, or are loosely attached to the inside or outside surface of the membrane. Carbohydrates are used to outline proteins and lipids to help cells identify them. They are only located on the outer surface of the plasma membrane and attached to …show more content…
It transports cholesterol across the membrane. “These mechanisms involve enclosing the substances to be transported in their own small globes of membrane, which can then bud from or fuse with the membrane to move the substance across.” (“Bulk transport,”2016) This mechanism allows cells to obtains environmental nutrients and choose certain particles out of the extracellular fluid. Also, they release signaling molecules to communicate. Active transport is when ions or molecules move against a concentration gradient going from a region of lower concentration to higher concentration. Carbohydrates are the molecules that are moved across the membrane during this mechanism. This process requires energy (ATP). Passive transport does not require energy to move molecules and other substances across the membrane. Proteins are the molecules, during this mechanism, that are transported across the membrane. Osmosis is the diffusion of free water across the semi-permeable membrane, whether it is artificial or cellular, so that both sides are equally balanced. It only transports water and phospholipids across the

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