our main focus for this video is going to be about ATP so one of the first important questions is what exactly is ATP atp's long name is just called adenosin triphosphate and I'm highlighting the atnp to just show you how it got its name uh of course students will ask me do I need to write adenosin triphosphate or ATP in the exam ATP is sufficient okay paper 4 is a long enough paper just the shorten form is sufficient so just like um any other biological molecule you must know the structure of ATP and here's the interesting thing ATP is actually a type of nucleotide if you remember nucleotides they actually have three parts which are the Pano sugar the nitrogen base and the phosphate group but ATP is a little bit weird in which it actually has a particular sugar known as the ribos how do I know it's the ribos sugar because in carbon number two it has the O group okay that's the first thing and it also has a particular base known as adinin which is a purine base represented by the two nitrogenous rings and another very important thing about ATP is it doesn't just have one phosphate group it has three phosphate groups that's why it's triphosphate and adinin and ribos collectively together are known as adenosin that is why the name is adenosin triphosphate so you do have to know the structure of ATP for the exam they may ask you to describe it or sometimes they might they might ask you to draw it out so just be vigilant about what may happen all right so the next question that we then have to ask is what is ATP actually used for okay in the future diagrams I'm not going to draw out ATP in its um you know that chemical structure on the left I'm going to represent ATP as adenosine represented as a rectangle and the triphosphate which are the three PS attached to the adenosin um so moving on ATP is an energy molecule and it's a type of chemical energy immediately some students will be like I don't get it you are saying to me that ATP is an energy molecule which is a chemical energy but in Chapter 2 of as I was also told my students will tell me I was also told that alpha glucose is an energy molecule which is also a type of chemical energy so which energy do I need because I've heard that glucose is a source of energy now I'm being told that ATP is a source of energy so which is it am I being lied to is it all a scam well no not exactly there is a relationship between glucose and ATP all right so let's just draw out let's just compare two of these molec ules over here ATP and glucose both are chemicals and both contain chemical energy now these ATP and glucose molecules are inside the cell represented in the you know the cytoplasm uh and you can see the cell surface membrane the phospholipid Bayer over there so the ATP and glucose molecule are inside the cell okay and for example over here I'm drawing out a celium okay Cel celium is the singular form for Celia okay Celia is Celia are are plural and celium is single but in my uh whiteboard uh notes Here I did use the word Celia so the Celia are important because what they do is they in especially in your Airway they are supposed to move the mucus upwards okay to prevent the accumulation of mucus the point of the matter is Celia need to move and they need energy to move okay so which which so my favorite question to ask my students is which molecule provides energy to the Celia is it ATP that provides energy to the Celia or is it glucose that provides energy to the Celia uh based on my experience 50% of students will say well ATP provides the energy but some of my students will then say no glucose is the one that provides the energy to the cyia so you see if the glucose molecule goes over to the celum okay um the the the celium is going to be like uh what are you doing I don't know how to use you okay like the glucose contains chemical energy but the glucose cannot immediately give its energy to the Celia so what needs to happen is the ATP is the one that is actually the usable energy required for cellular work because when the ATP goes over to the celium the celium is like ah okay I can use this energy G molecule okay so that is why ATP is referred to as the energy currency of the cell and glucose as the energy storage of the cell all right so energy currency just means that is the usable energy okay so for any chemical reaction in your cell like DNA replication active transport movement of the celum muscle contraction whatever they can only get energy directly from the ATP so then you might want to ask the question so what is so why do we say that glucose is also a source of energy okay I'm going to explain that in a while okay so just just just bear in mind just just keep that as uh just keep that at the back okay and we will talk about that later another way to talk about this is okay imagine like a a Note 10 Ring over here that's the currency from my country Malaysia and imagine a plate of fried rice 10 ring and the plate of fried rice also costs 10 ring as well so technically in terms of value they are both the same value however can you eat the 10 vingate note I mean you can if you wanted to I wouldn't advise that you do so but can your body directly use the 10 Ring note as a source of nutrient you can't you what you have to do is you have to use the ten linget to buy a plate of f rice which incidentally oh my God cost of living in Malaysia is really going up a plane of fight Vice 10 ring it totally ridiculous anyway coming back so uh what happens is you you um you convert the ten ring get into uh a plate of flight Vice uh by buying the flight Vice using the money and then you eat it it's the same thing with um glucose ATP and uh the movement of the Cilia the glucose represents the tening get what needs to happen is the energy or the value of the glucose has to be converted into ATP and then the ATP which is the energy currency can be is the usable energy that can be used for the movement of the Cilia I hope the analogy makes sense but we are going to look at it further in detail all right so then comes the question how exactly does ATP provide energy for cellular reactions so so just throwing out the cell surface membrane and the celium and the celium needs energy to move so for the ATP to provide energy the ATP needs to undergo hydrolysis hydrolysis means chemical bonds are broken down using water and now one of the phosphate group has separated from the you know the main branch and now it becomes adenosine D phosphate because adenosine is now linked or joined together to only two phosphate groups so you know that's why it's called diphosphate plus the phos inorganic phosphate Pi when you're writing it in the exam you have to put ADP plus p i or p uh capital I or a one is okay because if you just put ADP plus p p is wrong because that uh P represents the chemical element phosphorus so in the exam you have to put the word ADP plus pi just to tell the examiner that that is an inorganic phosphate not phosphorus it's a little bit nit they can be a little bit nitpicky so just be careful with that anyway coming back to this when the ATP under goes hydrolysis it releases energy and that energy is the one that is used for the celium to move okay so that's how it works story short over here the ATP is full of energy and when it under go hydrolysis it will release the energy and the energy is used for cellular work for example protein synthesis as you can see here the cell needs to carry out a particular work known as protein synthesis like for example transcription translation now comes a more important question you see imagine inside a cell the ATP is represented as those red dots okay so as ATP under goes hydrolysis notice what happens to the amount of ATP inside the cell the amount of ATP inside the cell reduces so now the cell no longer has any more ATP so if the cell does not have any more ATP what happens um is the cell doomed to die well not exactly because here's the beauty of ATP it can be regenerated from ADP and phosphate by joining them together through condensation but see when ATP is hydrolized to ADP and phosphate it releases energy so logically for ADP and phosphate to be joined together back into ATP it needs to get energy one of my favorite questions to ask students is where does this energy come from so if you're not sure that energy comes from the respiration of organic molecules for example glucose because remember I told you in the beginning of chapter the the earlier video respiration is the breakdown of organic molecules to release its energy the release of that energy is used to regenerate ATP by joining ADP and phosphates together that is the beauty of ATP it can be used hydrolized and it can be regenerated again that is a cycle that is happening right here