0:00 hi everybody welcome back today we're going to look at an introductory lesson to biochemistry first things first we need to look at the basics of biochemistry and that is looking at the compounds that make up organic and inorganic substances firstly let's look at organic substances organic substances are substances that contain the elements of carbon oxygen and hydrogen and to be more specific a substance is deemed as organic when the carbon molecule or element is attached to a hydrogen now some examples of organic substances that you may be familiar with is something like dna table sugar
0:47 methane and ethanol and even though they may have other elements present within them such as nitrogen phosphorus or sulfur each one of these examples has a carbon backbone that has hydrogen attached to it which makes it a organic substance there are some exceptions to this where there are substances that do contain carbon but it all comes down to the structure of the molecule and how that carbon attaches to a hydrogen this then brings me to our inorganic substances inorganic substances such as table salt carbon dioxide diamonds and silver all are examples of inorganic substances
1:33 and please note that carbon dioxide even though it contains carbon even within its name does not directly mean that it is organic in this instance it is not so what are the defining qualities between these two groups it all comes down to how do we put the elements together there may be carbon present however it really comes down to in what order do we put those elements and how are they attached to one another let's look at the first and the most important inorganic compound that we need to know which is water and it's essential for life and we could survive weeks without food but unless we have water we would die within a few days now water has a very simple structure
2:19 where it is made up of two hydrogen atoms that are attached to one oxygen atom now water is a polar molecule which means that one side is slightly negative charge while the other side is slightly positively charged and the molecules of water form hydrogen bonds with one another and these intermolecular forces are responsible for the cohesion forces between the molecules in other words the bonds that form in between these water molecules is what holds them together it would make it's what makes them cohesive now because water is polar in nature which essentially means that it's slightly more negative on the one side of the molecule and slightly more positive on the other side of the molecule it
3:05 means that water has amazing adhesive properties and these adhesive properties if you want to think of them as being able to stick onto something water adheres to lots of other substances very easily and it does it in such a way that they form very strong bonds and an easy way to tell the difference between adhesive and cohesive forces is that adhesive means for example when water adheres to something it means to stick onto something think of how water adheres to a piece of glass and you watch the water droplet run down the glass that's an example of adhesion cohesive is how water actually sticks
3:51 itself together and i'm sure you've noticed before how water when it runs down a window pane or runs down glass you'll see that the water droplets seem to run towards one another and pull each other into a much bigger droplet and that's because of their cohesive forces it is because water attracts itself and wants more water around itself water is also known as the universal solvent and essentially what that means is is that substances can dissolve easily into it think of how easily sugar or salt can easily dissolve into water and so because it's so easy to dissolve substances into water we often use it as the universal solvent or the universal substance in order to carry out experiments but
4:38 also within our own body it makes it easy for substances to move through our body because of water being present within our blood and in and around ourselves water is also really important because it's the main medium for chemical reactions in cells and essentially cells can go through different kinds of chemical reactions one being something like hydrolysis and that is when water is added to break down the bonds between molecules and we do this and we use water to essentially cut open molecules so that we can get the necessary elements out of them there are many other functions of water in the human body for example
5:24 we need water to cool the body in terms of temperature and that's linked to sweating but we also need lubrication we need protection and so things like mucus and saliva are mostly made out of water in plants however water is a very important component in maintaining turgor pressure turbo pressure is essentially the way in which plants stay upright they don't wilt and bend over and it's important that they maintain their water pressure the second kind of inorganic compound we need to look at are minerals and minerals essentially are dietary chemicals that we need to live and there are two kinds we get macronutrients and we get to trace
6:10 minerals or micronutrients now perhaps as the name gives away macronutrients are nutrients that you need in large amounts whereas micronutrients or trace minerals are required in much smaller amounts now plants can obtain their minerals from the soil but animals need to obtain it through the food that they eat and there is a large variety of nutrients that we as humans but as well as other animals need to be able to absorb and in doing so we need to take in these inorganic substances in order to maintain those levels within ourselves because we're unable to make any of these minerals
6:55 now these are just some examples that you can see on the screen now such as calcium magnesium potassium iron and zinc and essentially you get these in different dietary sources calcium you can get in cheese milk green vegetables calcium is often associated with the development of bones it's also really important for blood clotting your nerve impulses and in plants it's an important component of their cell walls the next vital mineral is magnesium and magnesium can be found in fish beans as well as some green leafy vegetables and whole wheat products magnesium is important for the formation of bones and teeth
7:41 for muscles and nerves and in plants it's important for the chlorophyll molecule next on our important list is potassium and potassium can be found in fruit vegetables and grains and its function is the relaxing of muscles we don't want it for the contraction we actually want it for the relaxation of muscles it's also there for your nervous system and it's needed for enzymes in photosynthesis iron is often found in liver meat but it can also be found in beans peas potatoes and green leafy vegetables and it's a really important component as it's required for the synthesis of hemoglobin which is needed for our red blood cells
8:27 it also forms a part of enzymes that make chlorophyll and finally zinc zinc can be found in dairy products liver and in wheat in particular and it's a very important component of many of our enzymes it's also extremely important in the brain development of a fetus now if you don't get enough of these minerals there are many different deficiencies or diseases that you can acquire through your lifetime if you don't get enough of these macro and micronutrients they can range from things like rickets osteoporosis muscle spasms abnormal functioning of the muscles in the nervous system anemia irregular heartbeat goiter
9:13 and cognitive difficulties moving on to organic compounds we're going to look at one of the most commonly known which is a carbohydrate now carbo means carbon and hydrate refers to water which contains the elements hydrogen and oxygen and most of our sources of carbohydrates come from things like sugar rice porridge potatoes pasta honey fruit and milk now if you have a look at the diagram here you will notice that the building blocks of carbohydrates are called monosaccharides mono means and refers to one saccharides are referring to these ring-like structures that you can see in front of you now
10:00 here we have three examples of monosaccharides we have glucose fructose and galactose each one of these comes from varying sources for example glucose can come from a starchy substance something like a grain fructose can come from fruit and galactose may be coming from a dairy product it's important to know that carbohydrates and the sugars associated with them are not necessarily sweet in taste we mustn't always assume that carbohydrate equals a sweet tasting sugar now monosaccharides are the building blocks of our carbohydrates it's what we call our monomers these are therefore the simplest of
10:46 sugars and they're also the most easily accessible sugars when we need them to use for bodily functions now remember the beginning of the video i mentioned that organic compounds contain copper carbon and as you can see in the pictures here these um monosaccharide molecules all contain carbons but it's a little bit unclear as to where the carbons actually are and the carbons are situated at each one of these fixed points that we see in this pentose shape but that's not the only thing that makes them a organic compound i also mentioned that it all depends on how the hydrogen molecules are attached to those carbons because essentially when it comes to chemistry
11:32 it is the order in which the elements are found which dictates its structure and therefore the structure will equal the function of that compound now if monosaccharides are the simplest or the monomers of our carbohydrates we now need to look at what happens when you string many of these saccharides together and what they ultimately form so now we have looked at monosaccharides and in this diagram here you can see that a monosaccharide is a single ring and our example here is glucose but you also then you get more complex compounds where you put many of those monosaccharides together and if you put two of those monosaccharides together you're going to form a disaccharide the example here is
12:19 sucrose and disaccharide literally means two and essentially what it is is you are going to take a combination of monosaccharides so for example sucrose is a combination of glucose and frac now if we were to take it one step further and we wanted to add many of those disaccharides or many of those monosaccharides together we are going to create a polysaccharide chain poly meaning many and in this example here we have an example of amylose which is a type of starch and you can see that we have our ring structures here that are joined together that form our polysaccharide chain an example of some polysaccharides that you may be familiar with are starch cellulose and glycogen
13:04 now carbohydrates have some very important functions and essentially they run on the most basic principle of providing energy for the organism so these particular functions of carbohydrates are things like an energy source which was what i mentioned earlier the fact that glucose is the most readily available energy to any organism but it also serves as a reserve energy source and that's the stored carbohydrates the stored sugars that we find in the muscles of animals as well as in plants in plants our carbohydrates provide structure it's the thing that gives plants shape and structure considering they don't have any bones
13:49 and lastly it provides dietary fiber and this is a particularly important in animals and their digestive systems in order to allow the matter to move through their digestive system successfully now we need to be able to test for the presence of starch and it's actually a very very simple test what you will need is some kind of indicator which in this instance here is we are going to use iodine and iodine is a indicator that will go from a brown yellow color to a dark blue purple color in the presence of starch and so if you were to drop a little bit of iodine on a potato or onto a piece of bread and their starch present then it is going to turn a blue black color whereas if you were to do the same
14:36 on a piece of um fruit or vegetable depending on whether or not there's any starch in there which they shouldn't be in any of your for example meat or in your fruit it would change any color it will remain brown yellow and you should be able to carry out this very simple experiment in class now we need to be able to take it one step further and we need to be able to test for a more large variety of sugars because starch is a complex sugar and it's just one of the many sugars that can be found another sugar that we should be able to be able to test for is reducing sugars and reducing sugars refer to anything like fructose glucose sucrose
15:21 galactose and essentially we need to be able to test for its presence and it's a very simple setup and the indicator that you need is called a benedict's solution benedict solution comes in a fairly vivid blue color it's bright and essentially once you follow the procedure of heating it correctly adding it to your sugar if there is any of your reducing sugars present it will change a shade of color and that color will determine how much of that sugar is present so it's a very simple method essentially what you're going to do is you're going to have a test tube with an unknown substance in it you don't know if it has any reducing sugars in it you're going to add your benedict's solution with a dropper you need a few
16:08 drops and then you're going to place your test sample in a water bath the water bath allows for even heating and you're going to boil the mixture for around five minutes and you are going to observe the color possible change that could happen so what is the expected results and what can the benedict solution look like so if you complete a successful experiment you would receive one of the following outcomes now it's a range of colors moving from the blue benedict solution at zero percent and moving all the way through to more than four percent and so as you can see it goes from a light blue benedict solution becomes more green and then into the
16:53 yellows orange is red and then finally brown and what that means is the darker the shade as we move through the color changes the more intensity and the higher percentage of reducing sugar is present in the test tube a nice easy way to make sure that you can actually see the color very carefully is if you do this experiment and you hold your test tube up to a blank white page it just emphasizes the color a lot better and it allows you to compare your test tubes so you could even use a piece of paper resting within the test tube rack so that you can have the test tubes side by side and you can compare the colors from darkest to lightest and so the next very important organic compound is proteins and proteins are really the building blocks
17:38 of life it's what the majority of um animal cells are made out of and they are really really important considering that they also make up enzymes i'm going to do a separate video on enzymes because they need their own video their own a specific explanation so i'm going to keep them separate from this and we're just going to focus in on the structure of proteins and the function of proteins in this particular video and what you're looking at here is a very basic structure of a protein where you have your amino group attached to your carboxyl acid group and then you have this carbon in the center which is almost like an anchoring point that allows you to exchange the different kinds of amino groups that sit on the edge here and this r represents where you would
18:25 attach a another amino acid and so on and so forth so you'd make a long chain now sources of protein obviously come from things like meat milk legumes which is beans grains as well as eggs and in order to take this chemical molecule and turn it into a living structure and being is quite a complex process and so we're going to look at how do we take something like this and turn it in to skin or saliva how do we turn this into muscle so how do we get a cell membrane a muscle how do we get something like cytoplasm how do we form those structures that contain proteins
19:13 how do we make hair all of that is linked to how we put amino acids together and amino acids are the building blocks of all of your proteins in total we have 20 amino acids that code for all the proteins found in every living organism on earth now these small subunits of proteins are not very usable as a single structure they need to be put together in order for them to function and when we attach many amino acids together via a peptide bond you create what we would call a polypeptide chain polypeptide meaning many or 50
19:59 amino acids attached together now what's really important about these chains that have formed is that the order in which the amino acids are put will determine what protein you make and so even though on the surface putting one or two small little building blocks together seems as though a small change would make no difference often the order in which these amino acids are put together in their chain is extremely important as it dictates their function essentially their structure equals their function now once we have enough of these polypeptide chains those polypeptide chains can fall in on themselves and they can become more
20:44 globular and essentially they then form a protein now proteins can take many different shapes and they can be fibrous think of something like your muscles which are fibers and compare that perhaps to globular proteins something like your blood cells are more globular the protein that makes them up and so essentially once you've made these long strings and essentially it looks like a long string of beads the way in which you fold them twists them will determine the ultimate shape of the protein and when we put all those shapes together we result in a much larger protein that has a very specific function if you change the structure of a protein you change its function now this is a very
21:30 important aspect of our proteins is that their structure dictates their function and in a separate video where i look at enzymes which is a specific kind of protein i will look at how things like temperature and ph affect the structure of enzymes and therefore affects how well they function so now we need to test for protein we need to see whether or not whatever substance that we have in front of us it could be an unknown liquid or an unknown substance does it contain protein and like our previous tests we need to use an indicator and the indicator that we use for protein is buret's reagent buret reagent is used to determine whether or not proteins are present and it contains sodium hydroxide and
22:16 copper sulfate and it is a light blue uh in color so that's the color it's going to start off but what color does it become when you add it to foods that test positive for our proteins and so if you look alongside here we have our buret's reagent that we are adding to our unknown solution and if you add it it should turn a deep purple color so a positive outcome is a deeper purple whereas a negative is that pure it's reagent will remain a light blue there may be varying shades of the purple and so it's just important to have use a white page behind your test tube and it sometimes allows you to see
23:01 the depth of the purple that forms it might be a lighter purple or more lilac color or maybe a very deep deep royal purple our final organic compound that we are going to be looking at is lipids which is also known as fats and this is a group of chemicals that includes phospholipids steroids and triglycerides now you may be familiar with what a phospholipid is and it is a part of the cell membrane it is a combination between phosphorus and fats steroids on the other hand are a collection of hormones that are fat based and they are responsible for maintaining homeostasis within the body as well as promoting growth and repair
23:46 and finally we have triglycerides triglycerides are what we call true fats it's usually things that you imagine to be such as fats oils things that you maybe would find in butter margarine cheese salami avocado and peanut butter now our triglyceride structure is alongside in the diagram and it has two types of building blocks that make it up it has a glycerol molecule which almost sort of forms the backbone of the molecule itself and it's an alcohol-based substance attached to that are our three fatty acids which sort of branch off here in three arms and this essentially is
24:32 a long chain of carbon and hydrogen atoms with an organic acid group at the very end and you can see why we call them triglycerides because we have three fatty acids with one glycerol now each time we actually form a triglyceride when we take these three fatty acids and we join it to a single glycerol water is formed and we call this condensation synthesis now we know the basic components of building blocks effect but what exactly are the functions of fat and there are actually numerous really important reasons to have fats in our diet our list of functions includes things like an energy reserve and it is
25:17 uh very importantly an energy reserve meaning that basically it's not our first source of energy it's a reserve that we would use if we've used up all the carbohydrates in our body the second thing is that it really is important to transport fat soluble vitamins these vitamins include vitamins a d e and k the third thing that we need fat for is insulation we need to be able to maintain our body's temperature in order to maintain homeostasis in other words we need to keep the internal environment of our body stable next it protects our organs and often fat collects around very important vital or organs in particular we find a lot of fat collecting around the abdomen
26:03 as a way to protect our organs in particular because there are no bones around them or perhaps there's very little muscle sitting around them the second and almost final function of fat is cell membranes and this is really important cell membranes are what holds our cells together it gives them structure it gives them defined shape and ultimately it determines what goes in and out of the cell and this is a really important function of fat because without a cell membrane you won't be able to regulate what comes and goes in the cell if you are unable to fix cell membranes with more fats you also run the risk of cell death and lastly we have waterproofing waterproofing is more prevalent in plants in
26:49 particular their cuticles that they have on the outside of their leaves and stems but in some animals as well waterproofing would perhaps be there in the feathers of birds and their glands secrete a waterproofing substance that makes sure that water just slides off their feathers now that we know the functions of fat we do need to take a little bit more attention into the structures and their structural forms that they come in fats come in a saturated form or an unsaturated form and we may be familiar with these terms in our daily lives in reading food labels but what does it actually mean well if we look at their similarities you will notice running down the middle in both of these structures are a chain of carbon atoms and they also have a outer chain of hydrogens but the main
27:37 difference is how we actually bond these together and you will notice in the unsaturated fats the bonding is slightly different and when you change the structure of something you ultimately change its function and appearance unsaturated fats are fats that we are familiar with in terms of plant lipids or plant fats and plant fats are things like oils and olive oil canola oil sunflower oil margarine and they are liquid at room temperature now how to identify an unsaturated fat is to look out for these double bonds that appear a double bond makes lipids melt very easily and that's why we find
28:24 unsaturated fats in a liquid form at room temperature the second fat that you are familiar with is saturated fats and saturated fats are our animal lipids they are saturated with hydrogen and that's essentially what it means to be saturated and that means that there are no double bonds so as you look down here there is no double bonding between any of our carbon and hydrogen atoms and these animal lipids can be found in cheese butter lard whole milk and essentially they're solid at room temperature so if you think of the main differences between the two fats it all has to do with their structure and unsaturated be more liquid-like and
29:10 saturated being more solid and of course their origins which is from plants and animals right now how do we test for lipids so a lipid test is actually a slightly more unusual one there is no component or indicator that you're going to add to the lipid instead lipids actually leave a greasy stain behind on filter paper and so the only thing that you actually need to do is take a drop of the unknown liquid drop it on some filter paper allow it to dry and depending on the stain left behind if there is any will determine whether or not there is any fat present and so for example if you have a look on the screen the water droplet is going to dry and it's going to disappear
29:56 completely if you allow it enough time however an oil droplet on a piece of paper which you might have noticed had happened before if you've ever dropped food on a page you'll see that if it sits there for a while it leaves almost like a greasy stain that doesn't go away it makes the page more translucent and that is the test to see whether or not a substance contains any fats or lipids so let's round off with a terminology recap remember biology and terminology go hand in hand when we explain ourselves so we looked at inorganic and organic molecules and we looked at what makes them different what makes a substance organic as opposed to inorganic substances we looked at minerals were
30:41 which were an example of inorganic substances as well as we looked at water and then we moved on to organic substances and we looked at monomers which are the building blocks of these organic substances each organic compound has its own monomer and in saying that we looked at carbohydrates carbohydrates have their monomers which we call saccharides saccharides can be mono dye or poly depending on how many you have we then moved on to proteins and we looked at their monomers and protein monomers are called amino acids and amino acids are connected to one another to form a long chain and we call those polypeptide chains take enough of those chains group them
31:27 together and you will form a protein we then moved on to lipids also known as fats and we focused in on particularly triglycerides which are made out of glycerol and fatty acids three fatty acids to every one glycerol hence the name triglyceride and we looked at its basic structure we finally looked at if you take those structures how do they influence the function and the resulting product and we end up with saturated and unsaturated fats saturated fats are the fats we find in animal products they are hard at room temperature whereas unsaturated fats are liquid at room temperature and we find those in plants once again if you have liked this
32:12 video please give it a thumbs up and i will see you again bye
