all right our chapter 6 material um is uh hopefully something that you recall from the previous video on chapter 5 uh something that um we are going to uh while working our way through it uh really emphasize the uh topics that you'll be tested on uh with the first exam um the reason for reducing um the uh topics that you would be tested on is because hopefully this topic on metabolism is something that uh you learned uh in uh&mp or general biology and you still recall um these important points um that we're going to continue to build on so at the very least uh you want to make sure that you understand this material going forward um even though um you uh will not be tested on you know every subject that we're going to be discussing here um the first exam is going to cover the first half of this PowerPoint so that's where this video uh will end is at uh the last slide for the first exam uh so our topic uh with chapter 6 is on metabolism metabolism we see is the uh sum of all of the chemical reactions uh that happen within a cell or organism and um those chemical reactions uh can go in two different directions um the first uh group of chemical reactions are referred to as anabolism and these chemical reactions um result in building a more complex molecule in order to build a more complex molecule uh this is going to require the use of ATP chemical energy so um the same way that putting bricks together to form a brick wall would require effort and energy uh same thing goes for putting amino acids together to make a protein so building a more complex molecule creating new bonds um requires ATP and is an example of an anabolic chemical reaction catabolism goes in the opposite direction this is a chemical reactions that take a more complex molecule and break its bonds and release energy from it and so uh catabolic reactions uh can be used in in some of the examples here to uh create ATP um more terminology relating to classifying chemical reactions uh we see the term oxidation is uh when an electron is removed from a molecule and we see the effect of removing electrons electrons are where uh chemical bonds were formed so atoms were linked to one another by uh sharing electrons so if electrons are removed the result is chemical bonds are broken so oxidation is uh a term for a chemical is breaking bonds within a molecule whereas reduction is the total opposite of oxidation and this is quite confusing because we see the term reduction you would think is reducing the the number of bonds or the number of electrons but it's actually going the opposite direction here so when you see reduction get mad at this word because it's it it should drive you crazy because it's backwards with its definition we see that reduction is actually gaining electrons uh within a molecule and the result of that is uh creating chemical bonds so increasing the number of chemical bonds increasing the number of electrons the term reduction um so a little background on metabolism and uh the chemical reactions that are happening within uh organisms um this is all relating back to a bigger topic on energy um the principles that relate to energy we see that energy can neither be created nor destroyed but can be converted from one form to another with an example of in the case of photosynthetic organisms they take light energy and they convert that into chemical bonds and those chemical bonds are now uh chemical energy so uh bonds between atoms uh contain energy um and uh this is uh the chemical energy is something that uh we rely on uh both as living organisms so when I need energy uh to do work I'm a keem organo heterotroof hopefully you remember this term from uh chapter 4 um I'm going to um consume molecules i'm going to eat carbohydrates lipids protein and then I'm going to break those molecules down to release energy and uh that energy is what I'm going to use to to drive my uh my activities uh so we see chemical energy in the in the biological world there but also there's chemical energy used all around you in everyday life you know for example gasoline is uh is a molecule that we combust in order to release energy from it by breaking its bonds so um in the biological world we are going to need enzymes in order to drive our chemical reactions and make them happen faster than they normally would uh in order to uh achieve the uh rate of activity that we need to survive and maintain homeostasis in an environment that's exerting a lot of stress on on ourselves um so an enzyme is going to uh uh be a a protein that with a three-dimensional shape that grabs a hold of a molecule called a substrate and drives it to go through a chemical reaction that produces a product so uh we see the enzyme is the uh protein it binds the substrate and after binding the substrate drives a chemical reaction uh resulting in the release of a product and what you want to understand about what the enzyme is doing is that um it is making a chemical reaction happen faster than it normally would have happened with less energy having to be put into the chemical reaction um we drive chemical reactions to happen faster in a laboratory setting by heating the solution and stirring the solution two things that add energy to the solution so we add energy to drive chemical reactions to happen faster in a uh chemistry lab but uh we can't exist at those high temperatures uh that we uh you know drive uh solutions to become in a chemistry lab bringing them up to boiling for example uh we have to exist at uh you know cooler temperatures at you know 98.6 degrees Fahrenheit um and so uh we need our chemical reactions to happen with less energy available to them uh we can't be as hot again as that boiling beaker so what an enzyme is doing is it is actually driving a reaction to happen at a lower activation energy so the chemical reaction happens more easily it requires less energy to happen than if the enzyme was not there this you absolutely want to understand understand for our test that what the enzyme is doing is lowering the activation energy of the reaction making the reaction happen faster because it requires less energy to uh reach the point of uh achieving the reaction so the enzymes will bind to the substrate at a point on their structure called the active site the active site is the uh three-dimensional space in which the substrate fits inside of the um overall structure of the enzyme and this is like a lock and key mechanism where the substrate is the key and it fits into the lock the lock being the uh enzyme okay so this relationship is very close um and and and it's uh what makes um uh chemical reactions so specific is that um enzymes are only going to fit a particular substrate now enzymes are not working alone they need help from molecules called co-actors so we see the role of a co-actor here it gets involved around uh the active site and the co-actor is going to uh in in combination with the enzyme help the enzyme to drive this chemical reaction um chemical reactions are going to require um either um the remember oxidation or reduction reactions they're either going to involve adding or removing electrons uh either um making new bonds or breaking bonds and the source of those electrons either to give or receive those electrons is going to be the co-actor so this is something that can uh changed by the chemical reaction uh without changing the enzyme so co-actors are essential for driving the chemical reaction to happen and more specifically we see here that um if co-actors are organic we call them co-enzymes so co-enzymes are our organic co-actors and we see that co-enzymes are typically derived from vitamins uh examples we see here NAD and FAD nad is uh a derivative of nascin which is uh vitamin B3 and FAD is a derivative of riboplavin which is uh uh vitamin uh B2 and so um we have um organic co-actors um serving as uh the what we call the co-enzyme it helps drive chemical reactions and once again um this is the role of many of the vitamins and so this is what vitamins are all about the the reason why you need food that is rich in vitamins is because we need these co-enzymes to help us drive our chemical reactions make sure you know what co-enzymes are make sure you understand the information here about co-enzymes once again that is one of the points I have just emphasized for you we see here that co-actors can also be inorganic um this includes magnesium zinc copper and other trace elements these are those um elements that you find uh on your nutritional labels in your vitamin and mineral supplement because uh once again we need these the same way we need vitamins uh to drive our chemical reactions and without them we cannot do the chemical reactions and if we can't do the chemical reactions we can't make the products we need we can't maintain homeostasis and we dysfunction and or die and that's true for us and that's true for the microbial world as well now enzymes are proteins and they are going to function best in certain environments we see here that uh enzymes have an optimal temperature and an optimal pH and an optimal salt concentration that if uh they are at that optimal point the enzymes activity is the greatest and we get the most product but if we go in either direction if the temperature gets too cold or too hot if the pH gets too low or too high if the salt concentration gets too low or too high we see a loss of enzyme activity this is why going back to chapter 4 we saw bacteria or microbes in general um having ideal temperatures phes salt concentrations and we said that anything that was too high or too low um always inhibited the organism's growth uh this is because the enzymes that drive the chemical reactions in the microbes only work best at certain temperatures phes and salt concentrations okay and we've used this term before hopefully you remember it here that um if the temperature or pH is uh at at any um extreme in the case of temperature too high in the case of pH too low um what will happen is the um uh protein that uh the protein structure of the enzyme will denature will unfold and um when denaturing occurs we see an absolute loss loss of the function of the enzymes so um this is why things like for example a fever would be effective at combating uh bacterial infection because the bacteria if we get them hot enough are going to lose enzyme activity and therefore uh have inhibited growth now uh enzyme activity is important we want to have our enzymes thriving and and very active but uh there are times when we want to make sure that enzymes are also not overactive we want to make sure that we have the right amount of product not too much not too little this is where the term alossteric regulation comes in understand alossteric regulation be able to explain this allossteric regulation is a process in which a molecule binds to the uh enzyme and changes its activity either increasing or decreasing its activity okay this molecule is not the substrate so understand that a molecule that is not the substrate is binding to the enzyme and either increasing or decreasing its activity so showing you how this can work in a logical way alististeric regulation is a process where uh an enzyme is going to be inhibited by the binding of another molecule we see this molecule here is binding to this enzyme and now the enzyme's active site no longer fits the substrate that used to fit into that active site but where did this inhibitory molecule come from we see that the inhibitory molecule can actually be the product of the chemical reactions that the enzyme is u driving toward so in this scenario here we see that this enzyme if it's uninhibited is going to start this process of turning the substrate into the product but when we have the product we see the product can come back bind to that enzyme and shut that enzyme down and so in this area when product is present the enzyme stops making more product so this is a beautiful mechanism to make product when we need it so if there's no product there's no inhibition and we make more product but when we have product it stops more production of itself so this allows for cells to create just the right amount of product not too much not too little when you have too little you make more when you have enough you stop making it okay and we have an example of alossteric regulation here relating to two amino acids in order to make proteins you need both thrienine and isolucine these are you have to have both of these but if you do not have isolucine thriionine can be converted into isolucine so we have enzymes that get us isolucine if we don't have it but remember we want both of these so we don't want these enzymes to go and turn all of our thrienine into or else we don't have any thrienine around so we want to have just the right amount of thrienine and isolucine and how we get this is that the enzyme that starts this reaction once we make isolucine is then inhibited by isolucine so when we have product we stop making more product so again understand and be able to explain that alseric regulation is when a molecule that is not the substrate binds to an enzyme and changes the enzyme's activity increasing or decreasing its activity and that is uh essential to make sure that our um cells within the human body but also the in the bacterial or microbial world that these uh organisms are um getting the right amount of product again not too much and not too little and what that point on alesteric regulation uh introduced is this concept of inhibiting enzymes um enzymes can be inhibited by uh molecules that get in the way of their normal uh chemical reaction but this can happen in a couple of different ways the first way is competitive inhibition in competitive inhibition we have a molecule that is competing with the substrate the molecule looks a lot like the substrate so we see competitive inhibition here this is the substrate this is the inhibitor the inhibitor looks enough like the substrate that it can actually get into the active site and block the substrate so a competitive inhibitor is basically just getting in the way of the active sites and therefore reducing the activity of the enzyme okay so understand that understand what a competitive inhibitor is doing a competitive inhibitor is a molecule that looks similar to the substrate it binds at the active site and it blocks the chemical reaction from occurring because it's blocking the active site understand that for the exam please but that's not the only form of inhibition we see the uh another form of inhibition is non-competitive and that's actually what we saw with this alossteric regulation this molecule um blocked the chemical reaction from happening without binding to the active site right the active site is is not where this molecule bound it bound uh at another point on the enzyme structure so non-competitive inhibition is non-competitive because it's not competing with the substrate the substrate's presence doesn't change whether or not this molecule can bind to the um to the enzyme because they're going after two different spots so there's no no competition but the effect here is that the non-competitive inhibitor binds to the enzyme changes its shape and therefore prevents it from binding to the substrate since now its active site has taken on a different form okay so we see application of non-competitive inhibition when it comes to aloseric regulation as this example here we see repetitive inhibition and how that's used with in this case this is a sulfa drug which is a form of antibiotic shows how we can use an antibiotic to block the activity of bacterial enzymes and therefore um slow down the growth of the bacteria uh so hopefully uh you can see the application of uh inition of enzymes as well and don't forget we need our enzymes to drive our chemical reactions and make them happen faster