Peroxisomes Research Paper

Peroxisome

Peroxisomes are small vesicles found in the cell which contain digestive enzymes which break down toxic materials found in the cell. These enzymes are oxidative enzymes, such as catalase and urate oxidase. Peroxisomes play a role in digesting fatty acids, alcohol and amino acids, and also synthesises cholesterol.

Hydrogen peroxide (H2O2) is produced as a by-product of these integral reactions, which is toxic to the cell. Because of this, the peroxisome breaks down this product down into water (H2O) and oxygen (O2). Peroxisomes are single membrane organelles and are thought to acquire their proteins by selective import from the cytosol.

Lysosomes

Lysosomes are specialised single membrane vesicles which, like peroxisomes, contain

As seen here, membranes consist of a phospholipid bilayer with specific proteins embedded in the bilayer. The bilayer is made up of phosphate heads and lipid tails. The heads are hydrophilic whereas the tails are hydrophobic. The amphipathic nature of the phospholipid molecules greatly assists the cell membrane in it’s selectively permeability. It helps the cell to transfer many molecules through the membrane. Many proteins can be found in the lipid bilayer and each has its own specific biological function. Integrins are transmembrane proteins which act as receptors for cell to cell and cell to extracellular matrix (ECM) interactions. Integrins attach the ECM to the cytoskeleton. It is this attachment which sends the cell messages and information about the environment surrounding it. There are 3 different junctions which join cells together and allow them to interact with each other. Tight junctions, desmosomes and gap junctions. Between them, these junctions fuse cells together, transfer materials and connect to the intermediate

It consists of 3 types of fibres; microtubules, intermediate filaments and micro filaments. It is a sturdy, dynamic 3D structure that fills the cytoplasm. The cytoskeleton has many functions including to provide structure to the cell and to allow the cell to change shape along with the intercellular movement of molecules. As the cytoskeleton is so big, it can easily change the shape of the cell by assembling and disassembling itself. Unlike other structures in the cell such as the ribosome the ratio of cytoskeletal proteins is not rigidly maintained allowing it to take on many shapes and to vary them easily. The cytoskeleton also allows organelles to move around within the cell by providing tracks with its protein filaments. This is important as it ensures the correct concentration of the required components is kept at the different sites within the cells. The 3 classes of filaments that make up the cytoskeleton are polymers made up of protein sub-units. The microtubules are the largest and provide the cell with its dynamic shape. It is these fibres that undergo continual assembly and disassembly. They consist of hollow rods and are made up of protein tubulin. The intermediate filaments are the second largest fibres and are responsible for the positioning of organelles and reinforcement of the cell. They are made up if diverse proteins for example