Vacuoles and Peroxisomes By Sam, Katie N, Katie V and Jess

Vacuoles Definition: A vacuole is a large compartment filled with fluid that is in the cytoplasm of plants cells and animal cells. A Vacuole is a storage place for sugars, minerals, proteins, and water. Vacuoles also store and help carry out waste from the cell. The vacuoles also increase the size of the surface area of the cell: This allows the absorption of minerals that are necessary for plant and animal nutrition. Vacuoles are filled up with a liquid called “Cell Sap” Cell sap contains the components of water, salt and sugar Vacuoles are not a part of the endomembrane system because they do not communicate with other organelles. General Information: They enable the cell to change shape. They help the cell maintain its internal pH They help isolate materials that might be harmful or a threat to the cell. They help the cell maintain internal hydrostatic pressure.

Animal Cell Vacuoles Vacuoles in animals cells tend to be much smaller then those in plant cells. Vacuoles in animal cells take part in the process of endocytosis and exocytosis. Exocytosis is the process in which directs vesicles to the cell membrane and endocytosis is the process in which cells absorb materials. In an animal cells, the vacuole fills with solid food particles being digested and waste material that is on its way out of the cell. Vacuoles are also a part of the process phagocytosis and pinocytsosis.

Plant cell Vacuoles The membrane bound sac helps with cellular waste products. Vacuoles in plant cells tend to be much larger then in animal cells. They play a very important role in turgor pressure, as water collects in cell vacuoles producing rigidity in the plant. Without sufficient water pressure in the vacuole is reduced and the plant wilts. In plant cells there are either one or more large vacuoles. The vacuole (s) occupies more then 30% of the cells volume and can be up to 90% depending on the plant type and conditions. Toxins in the vacuole can also help keep away predators.

Here is the electron micrograph of the plant Here is a paramecium, its vacuoles are distributed throughout the cell.

Where Can We Find Them!? Vacuoles are mostly found in plant cells, however they can also be found in animal cells. They are also found in protists which are eukaryotic cells that consist of simple organisms unicellular or multi-cellular without complex tissues and vacuoles can also be found in budding yeast cells which are a eukaryotic unicellular organism that are produced asexually by budding (no fertilization). The vacuoles are located in the cytoplasm of the cell.

Peroxisomes The are organelles found in eukaryotic cells – plant and animal They collect toxic peroxides which are by products of cellular chemical reactions Peroxides are broken down inside the peroxisome by enzyme catalysts enzymes that produce the toxic hydrogen peroxide are transported into the peroxisomes by the cytoplasm after they are synthesized by free ribosomes Vacoules and Peroxisomes are related because neither of them communicates with other organelles inside the cell

They are round or oval vesicles surrounded by a phosolipid bilayer Inside the vesicle are many, many enzymes Each peroxisome is a single membrane Each cell contains several hundred peroxisomes They resemble a lysosome but are not the same They are self replicating Size is variable, but it is roughly 700nm A peroxisome is found in the cytoplasm of a cell The organ that peroxisomes are most abundant in is the liver What they look like

Inside the Cell

Peroxisomal Diseases Three types of disorders related to peroxisomes: peroxisome biogenesis disorders, peroxisomal multi-enzyme disorders, and peroxisomal single-enzyme disorders. Peroxisomes biogenesis disorders: the peroxisomes do not work at all, or aren’t forming Peroxisomal multi-enzyme disorders: certain proteins inside the peroxisome do not develop, but the peroxisome still tries to do its job Peroxisomal single-enzyme disorders: occur when the peroxisome is working properly with the exception of a defect in a single enzymatic process (this sounds like the disease would be less sever but that isn’t the case) Zellwegger Syndrome is an example of a peroxisome biogenesis disorder. A child who is born with ZS would be very deformed and most likely suffers from seizures. It is a fatal disease, the average lifespan is about 1 year Rhizomelic chondrodysplasia punctata or RCDP is a multi-enzyme disorder that results in skeletal abnormalities, and causes many problems with the psychomotor development

Bibliography The grade 11 Bio Text Book