hello so I'm going to record the first part of the lecture on chapter number one about um introduction we I did post already a second part of the lecture I'm going to push the first one so microbes are Tiny But Mighty so they're both very easy and very difficult to study they reproduced rapidly can be grown quickly in large populations in a laboratory we call it culture so the way you do it you put a little bit of bacteria in your liquid or solid medium and put it in incubator which provides Optimum temperature to grow medium contains all the nutrients bacteria need to grow as bacteria um divide by boundary fishion more and more bacteria is formed so most of the time bacteria cannot be seen under micros well bacteria cannot be seen directly the you need a microscope to see them so we need um unfortunately we need tools like microscope and also you can analyze bacteria using methods like uh biochemical methods where you uh put a certain nutrient and then they degrade it there will be some sort of indicator in a medium that shows color change or some other property that you can deduce the bacteria there doing something okay so the nature microbes microbiology specified a biology that deals with living things so or too small to be seen without magnification so microorganism include different classes like bacteria Aria Pera fungi helmets algae viruses and prons out of all these guys viruses and PR are as cellular means they do not have cellular structure helmets are um parasites that live inside animals humans or plants they are most of the times visible with the naked eye however they some of their um stages of their life cycle are invisible like eggs and lar that's why it's all helmets are part of microbiology uh microbs have shaped development of Earth habitats for billions of years so we're going to go a little bit into history of life so single cell organs appeared on the planet about 3.8 billion years ago the planet itself is about 4.5 billion years old um cell types arose from a single um which is not living or extinct common ancestor we call them last Universal common ancestor so we do have um we divide the all living things by the way they structured into UK cariot and procaryotes UK carots have true nuclei um they include plants animals peroa they have the fancy cell that has a nucleus with DNA inside and has um organel like uh mitochondrian chloroplast Pro carots include bacteria and ARA they both single cell they have not true nucleus how are evolutionary distinct from bacteria so when we talking about uh taxonomic division like um you know talk about genus species female and so forth the procario is not a toxic division we have three domains UK cariot ARA and bacteria those are three domains of life distinct by comparing their DNA to each other okay so that's what we were just talking about bacteria AR can ukaria are three domains alive they've been uh originated from last common ancestor and if you can see ukar are um they have a CTIC structure they uh include uh plants Fung animal so forth they do have organel and membrane B nucleus B ARA are two distinct domains mean when you compare ARA to bacteria they sometime follow apart removed the Aria fromia although they both have no nucleus they don't have organal they look very similar the most important part to remember that based on their DNA compar they two vastly separate domains so this one is um a picture that depict uh a short origin of life I want to make sure you con disable it shows you that um according to scientific theory we had a last um common ancestor in about 38 billion years and it gave uh rise to bacteria ARA and ukaria uh and um after that we have um insects reptiles M so forth the from ancient eukariotic cells so microb are and are found deep in Earth crust the polar ice Cs and oceans inside the bodies of plants and animal they also found uh the central to life um we have many theories in science theory in science is um usually undergo years and years of testing and have not been disproved um it's usually a wellestablished uh natural phenomena and not just a random gas example of theories and science include germ Theory cell theory and theory of evolution so germ Theory we're going to talk about it um literally talks about how germs are um infect are uh causes of infectious disease and um cell theory talks about uh that everything is made of cells and each cell comes from pre-existing cells and the of evolution states that um explains the diversity of life and literally states that accumulation of small changes that occur in organism happen as they adapt to their environment um so literally um random changes which are called mutation happen in organis and if this change uh encodes a beneficial uh character that gives this organis survival advantage that change will be propagated in offsprings of that organism making it more adapted to the environment so um that little um that accumulation of changes that will U eventually lead to better adaptation because it's selected by environment documented every day in all corners of the planet and ATT testable by science so we're going to talk a little bit more about major metabolic processes so metabolism is all the chemical reaction that happens within the cell and one and the divided into catabolism and anabolism so catabolism are reactions that lead to breaking down of complex things into simple energy is been released and organis harvest this energy by making it into ATP now anism is the opposite is the reaction of synthesis where complex things are synthesized by using simple things and the energy needs to be inputed so photosynthesis this is a major metabolic reaction which has two parts photo means light and synthesis means making something so that's literally light fueled conversion of carbon dioxide to organic material so we literally take carbon dioxide and we build more complex molecules like carbohydrates like glucose out of it so the light is used as a source of energy so you guys probably heard how uh if you take a plan and put it under the glass Dome and you put um take oxygen out of that little Dome and uh let the plant grow and then put a little animal and they like a rat the rat will survives because during photosynthesis the oxygen is being produced that's just one type of photosynthesis it's called oxygenic photosynthesis that's what the plants around us do ssai and the bacteria do and a lot of little uh protoo that live in the ocean that's how they produce uh oxygen they take o water split it to hydrogen and oxygen take hydrogen to build carbohydrates like glucose because it has atoms of carbon and hydrogen in it and they um discard oxygen as a waste product so that's a second type of photosynthesis it's actually originated from a more ancient form of photosynthesis which is called anoxygenic photosynthesis so an oxygenic photosynthesis arose from first in the life in the earth history occurred in bacteria and it did not produce oxygen as a waste product it actually had hydrogen sulfide as a source of hydrogen and broke it off and the waste product was sulfur so um it's actually more efficient in extracting energy from sunlight however as ancient organisms were doing an oxygen photosynthesis they ran out of hydrogen sulfide and if they didn't um there was no um any other sources left that would have gone extinct but um as we mentioned about Evolution transmutations happened and that allowed uh certain organisms Swit to using water as a hydrogen donor and that led to emergence of oxygenic photosynthesis we still have an oxygenic photosynthesizing bacteria around they live in anoxic environments environments with no oxygen and you'll be surprised how much of that we have uh if you go to sediments of lakes or swamps or even um certain parts of ocean where there is no oxygen you can find an oxygenic photosynthesis size in organis there as long as there's light and no oxygen and donor like hydrogen suide you can find them um so we're going to talk more about how we just talked about how microbes produce oxygen as a result of oxygen photosynthesis they also produce CO2 as result of deg and and and ch 3 which is methane as a result of degrading organic matter because a lot of microbes are decomposers they decompose that things and uh release all these gases um so as we said bacteria the most abundant cell organism in the oceans and the number one photosynthesizers what does this mean so we know that a lot of plants do oxygenic photosynthesis make oxygen for us however even if in theory all theoretically all the plants were gone we would still have enough marine organisms to produce oxygen for people to live on so so if we're talking about most abundant cellular organism made cells this case procaryotic cells there would be bacteria most abundant as cellular inhabitants of oceans would be viruses so viruses do not are not part of tree of life because we can't compare them with the rest of the organism because the three domain of life lives are based on comparison of 16s RNA Gene which is part of genomes of those organism and they encode 16s ribosomal RNA which is a part of ribosome viruses do not have ribosome that's why we can't uh use them and they do not have cells so they are not really truly alive organisms so when we talk about bacteria we already mentioned that some bacteria act as primary producers they actually make organic compounds using photosynthesis some of them act as decomposers because they decompose um dead things but they also um some of them live in close uh proximity in in symbiosis with plants um and F and and also um fungi live in symbi with plants and both bacter fungi assist plants in getting their nutrients however one more thing that we will stress in our class is that about 2,000 species of bacteria are pathogenic they cause diseases of animals and pl and humans so we're going to talk more about uh historical current uses of microbes by humans so as we talk about micos the first thing that comes to mind is a process called biotechnology where people use microbes to produce certain value added uh products like bread alcohol and cheese and yogurt so as people were applying bacteria and yeast to make this above mentioned products uh as our understanding of genetics Advanced uh people realize that they can actually take that organism and modified genetically to make it a better producer so manipulating of genes of uh modal organisms actually is a Hallmark of genetic engineering that allowed us to um manufacture things like insulin by creating recombinant organism what is a recombinant organism or GMO genetically modified organism is where you have a model organism like bacterium or yeast and you insert a gene from maybe a human which encodes insulin or any other biologics and you um grow that GMO in culture and as this uh modified organism grows it will manufacture a product that is encoded by the gene you inserted into it like insulin before we could uh make insulin using genetically modified organisms people had to go and harvest insulin from cadavers which dead bodies and that was not very efficient practice however now people can manufacture a bunch of insulin and for the price of you know $30 a vial of insulin which is uh can be life uh supporting for somebody with diabetes type 102 so using genetic engineering biotechnology literally allows people to save lives of hundreds and thousands of people so as we mentioned uh people use genetic engineering to create genetic modified organisms where they can use them as um producers of value added chemicals like insulin so all this is parts of recomb DNA technology which allows transfer of genetic material from one organ to another and that will literally making their DNA different um to allow us people to take advantage of that and make products we want to make in Mass scale okay so the practice of medicine allowed us to uh Advance our treatment of wounds and lesions uh perform operations and um ma major discovery of antibiotics actually revolutionized medicine allowing us to um prolong people's lives save them uh from infection and operation table and any other infection uh situations another way of applying organisms is in Industry like mining precious metals like gold where organisms are used to purify gold and and biom mediation is another way of using microbes uh in industrial settings where um um we use microbes already present in the environment or introduce them their intentially to restore U stability of the system or clean up toxic pollutants for example when you have um major example is when we have big p oil spill we had um in in Gul of Mexico uh we introduced uh a a surfactant which is a soap to break down the oil into tiny droplets and um bacteria that was already present in the Gulf of Mexico because it had some oil sips they are naturally adapted to uh break down hydrocarbons like oil that breaking of the oil into tiny droplets allowed increase the surface area and allowed the microbes to do better job of breaking down the oil um another uh thing we mention is that over 2,000 different microbes uh microb species are pathogenic that means they can harm people animals or plants and cause disease 10 billion infections still occur across the world every year um in so majority of the infections are coming from respiratory infection agents like viruses like Rhino viruses cold viruses uh bacteria are actually uh behind viruses so unfortunately infectious diseases are still uh if you compare United States of the world you can see that the pink uh circles indicate diseases um that uh caused by microbes and and blue uh circles indicate non-infectious diseases so top cause of death in United States we have top five heart disease cancer accidents low respiratory diseases like COPD and stroke COPD usually caused by a previous lawn damage caused by smoking or maybe living in some toxic um zones where there is Toxin chemicals that damage lungs um however in worldwide we see that um the pink circle which is called Low respiratory disease uh it's in Pink So in this case this low respiratory disease is not caused by smoking caused by um infectious agents like um pneumonia uh streptococus pneumonia bacterium and other uh flu viruses so it's still um in within the top five causes of death we also have diarrheal diseases number nine and tuberculosis number 10 uh the only pink circle we have in that causes death in United States is influenza and pneumonia and it's within top 10 so if we talk about influ and pneumonia is not that it kills younger people majority of of the people it kills are people are older than 65 that's why guys if you ever a go and how you if you although our unfortunately our flu vaccine is only efficient about 70% of the time even if everybody vaccinates we can achieve her immunity and protect older people from getting pneumonia because a lot of the time it's fatal for them so um uh so let's kind of talk about um emergent diseases so when we talk talk about emerging disease are diseases that actually emerged recently in in maybe within last 20 or to 50 years and the one of the most important ones is AIDS um we still have uh although we do have very efficient medications for AIDS people actually while taking meds they can live their life and not even be contagious um it's still considered a very important disease then we have Hepatitis C which affects liver cells we have zika virus again um we're going to talk more about it West n virus and tuberculosis so tuberculosis is not really emergency diseases and old diseases see but it is can be called a reemergent disease because if people um in certain developing countries go through maybe a conflict where you have like refugee camps and and they are all housed in close proximity tuberculosis submerges and can spread in this type of uh circumstances so also uh apart from U talking about emerging or emerging infectious disease there were some Association found between non-infectious diseases and microbes so for example everybody knew about gastric ulcers and from you know 16 or so Century which is literally ulcers forming within the stomach lining however later in about 1970s and 80s uh it was discovered that everybody who had an elcer also had a bacterium called Hela pylor and it took a brave resident who had it doctor student medical MD student who was in his residency he actually tested himself um and he was negative for H Lori he actually grew in culture and gave himself h p infection by drinking it and was U monitoring himself within first few months about three four months he developed stomach ulcers he treated himself with the c of antibiotic and the ulcers went away and he uh tested negative for h pylori so he literally uh proved that H pylori was a causeing ulcer together with other things and if you treat a patient for hpor infection with antibiotics the aler will also go away the problem that a lot of people get reinfected with hpor because it's in every um if you have seafood and any other things like that it's very common so about two out three or one or three people in the world infected with hpor but not everybody who's infected develop uh stomach ulcers unfortunately one or two% with h pyloric who did develop stomach alers will go go on and if untreated will develop stomach cancer as well so it is still a mystery why h p causes stomach alers and cancer in some people but not in others uh research Searchers thinks that genetic factors are involved so other things like multiple sclerosis OCD coronary AR disease and obesity have been linked to Chronic infections with certain microbes and if we modulate uh composition of microbial communities we can modulate presentation of those diseases as well so um so increasing number of patients with weaking defenses are subject to infectious by Common microbes there are not pathogenic to healthy people so what does this mean we have some um people with lower immune system function that are more susceptible to infection with bacteria that are not infecting normal healthy people and also we have another uh trend is increase in microbes that are resistant to drugs so we introduce a new antibiotic in the market it takes about 2 to four years for new resistance strain to emerge so we already mentioned divisions of all living things that are non-toxic are UK cariot and pro cariot so UK carots uh includes a single domain um they have membrane organel and each uh generally larger cell size most multicellular organal is small double bound structures that perform special functions they include nuclear mitochondria chloroplast um so some ukur are microorganisms like protoo for example you need microscopes to see them that's are microscopic they're multicellular like animals and plants that you can see with the naked eye and finally we have a second group procaryotes and although they do form a um they belong to two separate domains so if you compare the DNA they evolutionary distinct uh and they bacterian ARA they do not have organiz the is free swimming in the cytoplast there is no nuclear membrane around it they're about 10 times smaller than you car it so although they do not have organel they have a very complex uh internal organization of of their membrane so membrane forms compartments which allows them to separately run processes like photosynthesis respiration synthesis of new uh parts of their cell wall so that compartmentalization is essential and it's found in the procaryotic organisms and then we did mention viruses and prons they both are as cellular organism so that means um they do not have cellular structure they are not made of cells so viruses are obligate parasites they need host to reproduce they're not independently living organisms they um exist at the level of complexity somewhere between large molecules and cells so literally if you look at the virus you'll see RNA or DNA molecule that is wrapped with special uh structure called CAP seed and cap seed is made of repeated capsomere it's almost like chain link on a on a night where you have this tiny uh you know links connected to each other to make the chain link so the same thing here happens in viruses you have the chain link structure made of individual protein subunit surrounding that DNA uh and pro creating protective sheet of some sort okay so viruses can either have DNA or RNA they never have both okay so now prons are even are weirder prons do not have any DNA or RNA components they actually are a single molecule of a protein that is infectious so what does this mean so if that protein uh prion comes in contact with a normal uh protein from brain cells it's actually initiate um the normal protein changed into this infectious protein confirmation and that confirmation disrupts um function of normal brain cells that actually uh activate um certain cells inside the brain that act as immune cells and they will consume this uh that deformed proteins by and that will make holes in the brain causing spongiform and sephtis so we know it as Med cow disease or also another part of this disease another manifestation happens in humans and it's called Cil Jacob disease so again we just went through viruses and prons they're both as cellular they do not have cells uh viruses are made of nucleic acid plus protein um nucleic acid being either RNA or DNA and PR are made just made of proteins so as when mentioned there are six types of microorganisms including helmets fungus Pon bacteria viruses and prons and although helmets can be visible for the Naked Eyes the eggs are not visible so um we're going to talk about how microbes and their role in disease uh and other processes like fermentation were done during history so there were two groups of people uh they believed in um so-called by Genesis versus bi Genesis so first group believed in Abbi Genesis which embraced that if you throw certain things together they are non living the living thing spontaneously arises so example they said if you open a little cupboard and you put a bunch of old clothes in there and some oil and some uh dirty laundry and close it the mice will spontaneously arise from that which is sounds like a very silly assumption but people did truly believe it's really happened so that was Bel to be happening because there was a vital force that was just present everywhere and it was able to summon a living thing out of nowhere so that theory was called abiogenesis or spontaneous generation um so that was first kind of camp and the second Camp the other Sciences said well this is BS you can't just do that there is no things coming out spontaneously they usually get into whatever you uh put it like a vessel or you know enclosure they they kind of get in there from the outside so nothing forms from non- living things spontaneously so there was the sciences that we're going to look at his contributions his name was Lou Pastor he lived in France he studied the roles of microbes in phation of be wine he was actually chemist by training not microbiologist and when his times fermentation believed to be a totally non living process like just purely chemical he didn't know about enzymes but he thought they just present in you know beer and wine and just happened to be there and do the thing okay so they thought it was like plant related or something however um he was interested in this biogenesis versus a bi Genesis like um the normal what we now accept bi Genesis so so the living things only come from another living thing um and he kind of wanted to once and for all disprove that spontaneous generation happens and he designed special SW neck flask experiment so he filled flask with broth and shaped the openings into long one neck tubes he heated the flask to sterilize the broth so as we said microorgan were already discovered way before L pasture in 1600 so people knew the were micro organs and they knew if you heat the liquid you'll kill them okay so that was not the news to anybody however um so he his experiment was a novel thing right so after he HED the flask and all the bro was telling both flask he treated them differently one flask was exposed to dust from the air um and another floss was exposed to air but not to dust and that showed no microbal grow so let's just kind of look at the picture and make sense of it so this is your flask right he kind of um like heated them and he exposed to uh dust and air by breaking off this uh flask and in some scenario he actually laid the the flask on its side um and Airborne microbes entered and growth occurred in the sterile environment in the medium however in the N flash there was was left intact the air was still going in right and however the organis couldn't penetrate it due to the nature of this uh swan neck and so the broth remained um intact so that was the last nail in the coffin for spontaneous generation so we're going to talk a little bit more about Robert Hook um and Anthony van lein hook so Robert Hook was the first scientist who uh studied household object plants and trees using first microscope he described first microbes uh and described cell structures so he actually named cells cells so he actually observed dead plant tissue cork that's the one that they use cork for oak trees to make corks for their wine bottles and he happened to observed it and he found that they structured like little cells gel cells on top of each other and that's why he called all cells we see cell okay and guys remember plant cells have durable cellulose made cell walls that's why he you know that organization really inspired him to name them cell but if you would have looked in animal cells they have no cell wall so they have a regular shaped so he might have been called them something else right it's kind of a serendipitous thing and finally so Robert Hook was also making discoveries in physics and other Sciences he was kind of Victorian gentleman and we also have a um another scientist that lived he was not really a scientist he was a merchant Anthony vanin hook look kind of he's he was a contempor of Robert Hook was inspired by him he was actually a a fabric Merchant that means he um like manufactured fabrics and one of the quality control steps was to look and en count the fabric fibers using microscopes and again those microscopes were very primitive you had to bring them super close to your eye to see anything and it was kind of annoying him because he couldn't count you know he had to use it every day you know to to do quality control and he was really aggravated and so he actually set out to to make a better microscope so he can see better his fabric right and so because of that and because of his Natural Curiosity he actually started observing all kind of liquids and things around him he observed animals in a drop of water he call them animac because they were so tiny he also scraped um you know his teeth kind of thing and because you know the back in the day people really didn't brush their teeth that much plus he also looked at his um his sperm okay and he he observed spermatozoids and he also looked at his own diarrhea guys that's how curious this guy was and he discovered um a protozoan in his stool which is called JIA lamblia and unfortunately that protone is not caring his name uh but he was the first one to describe it and JIA Lam is still around today it causes infection of of intestinal tract of all kind of while the animals including beavers and other animals that live around the water so if in some areas of United States like Kentucky uh this disease that caused by people drinking contaminated water with jaria it's called beaver fever so this also happens in some parts of Colorado where people just drink water from un untreated water from streams it seems clear however it might carry cyst of jaria and as they drink it it gets into the intestine uh small intestine develops into adult organism it's it's actually plants itself onto the V of the small intestine and um reproduces to such an extent that it's impairs absorption of fats so as the um food goes through the person with that disease the fats are not being absorbed it's actually causes certain malnutrition people might lose weight and they produce this explosive foul smell and diarrhea which is floating and is high in fats and it it's called stara okay obviously the diet is high in fats right so so Jia lambl was first discovered by anony m hook so we also have three other Sciences for non Oliver Wendel homes and ignash S wise in law Joseph liser so Fern con Conor was working alongside uh KO Robert Koke which who was um one of the U contributors to germ Theory and F now Co discovered uh described heat resistant endospores certain back it's now we know endospores are special bacterial cells they have a really really thick cell wall and they can survive boiling for 4 hours um and they you only can Dort them using U sterilizing methods like out of claven where you apply high temperature and high pressure um Oliver Wendel Holmes and ignas chalas describe the importance of handwashing in preventing disease in hospital settings and I did tell you story that ignas swise was a doctor who was working the fancy hospital where they had three stories in in the first story they had clinics and the second they had maternal world and and they also had um Al y room so a lot of the times doctors would perform autopsies trying to understand why person had died and then they would run to maternity War to to to help pregnant ladies to give birth and ignas was just taken by surprise because there's so many women that died of sepsis in this Hospital while giving birth because across the street they had a a a kind of a midwife place where all they did was uh helping mothers to give give birth and they didn't have nearly as much maternal death there so he was like how is this possible we have such an advanced hospital and we have so many more mothers dying and he actually figured out that when doctors come back from autopsies they obviously didn't wash hands and they literally stuck those hands inside the you know if you had hard delivery the mothers would get sepsis from those doctors and he was trying to tell everybody to start washing hands and how it's important and it took few decades for people to actually catch on so that was aiz story and story of hand washing and story of a septic technique being established in the hospital so a septic technique is a a bunch of things doctors and some researchers do to prevent contamination of sterile area so when doctor is gwn into the gone and into the mask the doctors is trying the surgeons are trying to prevent their own contaminant rich and sterile cut into the human body that operation they perform another example of aseptic technique is when you trying to make a pure culture of your organism and you prepare the medium you sterilize it and when you put the microb you wanted to grow in there we call inoculation you trying to prevent any other contaminant from the air to get in there by using flaming by using steril uh flame sterilization of your Loop and things like that so those are a septic technique and the first people who paved the way are alliver wend homes in shamas and Joseph lster also was the one to use a septic T in surgery so literally that's um where we kind of stopped and now next lecture was with germ theory of disease where we talked about Lou pastur and Robert Coke so Lou pasture invented pasteurization uh which is a gradual heating of a solution like milk or beer to kill majority of the micro organism you can't outter clay or sterilize milk simply because it will break down because it's a complex Emulsion okay so pasturization a special thing that kills majority of organisms in beer and milk and other um food product Louis pasture we also know this proved spontaneous generation using swam neck experiment that we just talked about he also contacted div vertiz linking human disease to infection so uh before that people did not really know what caused diseases like an example is that the word malaria meant bad air so they thought if you inhale bad air from the mops you get malaria but now we know that it's actually carried by mosquito and it's caused by a proo so the This research that was done to link human disease to infection to infectious agent uh done by Le Bast Turner butt Cole contributed to development of so-called germ theory that said that germs or infectious agent cause diseases in humans um so Louis pasture actually developed rabies vaccine he didn't know anything about viruses he did not know um um you know about rabies that much but they knew that the rabies are transmitted to humans through R bites of rabid animals so Louis Pastor did develop rabis vaccine by um passing the um rabis virus through different animals so he literally took a CSF sample cereal spinal fluid sample from um infected people and he passed them through animals giving them to animals and making virus less uh deadly and then he took CSF from of those culture animals and they contained weakened virus and the virus actually gave resistance to rabies and saved the life of a little boy uh that his mama mother brought it to him to B and ask for help because everybody knew he was going to die because everybody knew rabus is incurable but that vaccination saved his life however let's just make sure we don't make mistake the uh Louis Buster was not the first inventor of vaccines the first invent vaccine was ever virgin Jenner but Lou Pastor did go into his in his footsteps and develop rabes vaccine and Robert Co contribute also was important researcher contribute to jump Theory as well and he actually established four postulat that we listed here we have to make sure we remember them okay so as organ State the four criteria are so first the microorganism the pathogen must be found disease but not healthy individuals the migrant must be cultured from disease individuals like you have to uh uh actually grow it in pure culture using the septic techniques and a solid medium then you have to take the culture inoculate a healthy individual maybe through inhaling or maybe injected into blood and that a healthy individual we mean that maybe a healthy maybe maybe like a healthy lab rat or something and the margin must recapitulate the disease me repeat all the signs and symptoms and and and if the micr might be reisolated from that disease animal and match to original microorganisms so Robert Koke showed that antrax was caused by basil anasis and he also was showing that microbacterium tuberculosum caused tuberculosis so we're going to stop this right here because the next lecture is going to pick up from discoveries of restriction enzymes and things like that so um I'm going to finish this and we have one more little tale of this lecture that I will probably go over the next class