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Current time:0:00Total duration:5:43

Lysosomes and peroxisomes

Video transcript

lysosomes are membrane bound organelles that are found in the cell what do they do well if you look at the word lysosome you can see the root lice which means to cut or digest so lysosomes digest various molecules and substances and we can break this down into two different processes the first is Lata Fuji and the second is chronology well tapa G literally means self eating so what tava G is when the lysosomes digest molecules that are part of the cell itself or other cells so for example if there are organelles in the cell that are no longer functional they will be digestive and lysosomes so if there are some mitochondria or other organelles floating around that are old and not functioning properly the lysosomes will break them down another example of what ofuji would be the macrophages of the immune system so macrophages of the immune system will engulf bacteria and viruses and then they will go to the lysosomes and be broken down over there let's focus on chronology chronology is when the lysosomes digest excess secretory products so let's say for example if certain cells producing a hormone to be secreted and the cell for some reason produced some extra of that hormone all the extra hormones will be broken down by the lysosomes and in both autophagy and chronology after the lysosome finishes breaking down the molecules it will release into the cytoplasm the building blocks that are just formed it didn't exactly form of those building blocks but it broke the molecules down into their most basic basic parts and those basic parts will be put into the cytoplasm and be reused so for example let's say the lysosomes digested some extra hormones that were lying around and those hormones were made up of proteins it'll bring those proteins down into the individual amino acids and then those mineral acids will be released into the cytoplasm and they'll be used for something else what's the environment like in the lysosomes well the enzymes in the lysosomes are known as acid hydrolases and they're known as acid hydrolases because they require an acidic environment in order to work properly so the pH inside a lysosome will be approximately 5 this acts as a safety mechanism for the cell how so let's take a look at this lysosome right here on bottom let's say for some reason it burst and released into the cytoplasm all the acid hydrolases that we just learned are capable of digesting organelles well we said that in order for them to work properly they need to be in an acidic environment but the cytoplasm has a pH of approximately 7.4 and therefore these acid hydrolases are not going to function properly you might say well when the lysosome bursts doesn't it release an acid into the cytoplasm and that's true however it's still going to be a pretty small amount then it'll get diluted in the cytosol and the cytoplasm will still remain overall at a pH of about 7.4 however if many lysosomes burst at the same time it would release a larger amount of acid into the cytoplasm and then and then the cytoplasm might actually become more acidic and the acid hydrolases will start to work and will start to digest the various organelles and this generally speaking would not be a good thing for the cell let's talk about another membrane-bound organelle that's pretty similar to lysosomes and they're known as peroxisomes peroxisomes are responsible for a variety of metabolic activities in some cells they're essential for a lipid breakdown they help liver cells detoxify chemicals and drugs but we're going to focus on one important task that they carry out so let's zoom in on one peroxisome here it is so what do you do well there are various enzymes in the cell that as a result of their activity they produce a byproduct hydrogen peroxide which looks like this hydrogen peroxide happens to be pretty dangerous for the cell so what peroxisomes will do is they're going to isolate it so the hydrogen peroxide ends up in the peroxisome and each peroxisome has an enzyme known as catalase and this enzyme is able to break down hydrogen peroxide so let's write out the reaction hydrogen peroxide in the presence of the enzyme catalase will become water and oxygen I'm just going to put a half there to keep the ratio correct so peroxisomes protect the cell from the damaging effects of hydrogen peroxide by isolating it and by then breaking it down into water and oxygen