 Hello again in micro molecules everything makes sense only if we put things together So let's see some of the examples how everything is connected in our body Let's talk about say like lactose intolerance. So that is connecting carbohydrates sugar what we already mentioned and How come certain people are not able to break down the lactose? What are the enzymes enzymes that are catalysts enzymes are the ones who actually Put things together and separate them. They're controlling how things are happening in our body how processes are happening in our body so The enzyme that is breaking down like those is called lactase and Let's say that this is just part of the lactase polypeptide and The lactase G In the case so this would be how the polypeptide should look like in the functional enzymes but in the case that this particular C is Converted it will lead to the wrong Reading to the codon and there are three stop codons in our system and That instead of having tryptophan here will lead to the stop to the discontinuation of This particular Polypeptide what does it mean that people who have this condition and This change in their genes are not able to break down Lactose into glucose and galactose What it has to do with geography? if You trace what is the number? What is the percentage of the people who have lactose intolerance? There is a different percentage in the Mediterranean region in comparison to say like Nordic Countries as the people were moving toward the north There was greater need for Capability to digest milk now. Let's think about two different factors here two different environmental factors how they're carving the Incidents of the the the frequency of the certain genes in our population First is temperature. What is normally happening when we leave milk outside in the? warm weather it will go spoiled really quickly in order to prevent spoiling people Fairly early in our history realize that they can make Products like dairy products like cheese and so forth. What does it mean that bacteria that are used in making those products are able to Breakdown lactose into glucose and galactose. So it really didn't matter. There was no natural selection that was Forcing people who were not able to produce lactose to be in a way eliminated from the population so Pretty significant incidents of the or the percentage of the people who are unable to To break down like lactose are in the Mediterranean region in the warm regions However, as we go north obviously it was more important for people to Be able to utilize milk as a source of vitamin D because in the colder areas our body is covered with the clothes as The vitamin D source as milk is source for the vitamin D. It was advantage To have lactase that is functioning. It was advantage if people were able to Digest milk so it was positive natural selection toward higher percentage of the people who are able to Digest milk to the just actually like lactose from the milk Now let's talk about different Harbohydrates to and and different enzymes. I'm sure you've heard about termites. How termites can they just? Wood and cellulose and break down the house and everything actually termites cannot produce the enzyme that is breaking down cellulose and as you already Can guess the enzyme that is breaking down the cellulose Is cellulase? Okay, who is then doing the job? Termites do have in their guts Bacteria that is producing cellulase and that is mutualism that is helping both species to thrive similar situation is with herbivores cows Deer they all do not produce Cellulase as an enzyme much like we don't you know the fiber that is what we need to have so that our Intense thing is Moving better, but we are not digesting it. Okay so how our Animals were grazing actually utilizing that because they also have bacteria in their in their Intense in their stomach that is producing cellulase and therefore breaking it into the components than then into the glucose actually that Mammals can utilize Metabolic pathway everything in our body is actually done in several steps sometimes 20 or more steps So this situation that we have a substrate that directly goes into product is extremely rare If not impossible, so this is not how our body works how our body works in In order to produce from Substrate a the product all the way at the end it goes through the series of intermediate products for each and every of the enzymes here we have Substrate which is in this case B is a product now this B becomes a substrate To the enzyme to and the C is the product that is made And the same goes For all the metabolic pathway Now all of these enzymes are different Each of these enzymes is a protein that has its own gene on the DNA Okay So Can you think about what can happen if for instance there is? One enzyme that has mutation, you know remember like the one that has a stop codon or for whatever reason is not working Say like if this one is not working What happens? We have C there is plenty of substrate But we are missing the enzyme that can convert it into D this Particular product can be harmful and In the case of phenylketonuria that is one of the reasons why to avoid complications we have labels now that are showing for each and every Product that we are using in our in our diet if it has phenylketonuria or if it has a phenylalanine or not That is helping people who have conditioned this called phenylketonuria to avoid Taking phenylalanine at the first place and therefore to avoid Accumulation of the product that is impossible for them to process any further Similar situation is with sickle cell disease Sickle cell disease is a mutation that is leading to the form of the hemoglobin that has different shape and Leads to all variety of the conditions as a result of it Enzymes are extremely important. They are working in the form of shape. You can think about key and the lock and Each and every molecule that our body is producing has to have their own enzyme that is processing it Thank you