hi everyone this is teacher issa maria and welcome back to my youtube channel for today's video we are going to discuss biomolecules what are the learning objectives number one identify the major categories of biomolecules number two distinguish between the structures and functions of carbohydrates proteins nucleic acids and lipids and the last one cite the importance of biomolecules in our life let us define first what is biomolecules biomolecule is also called as biological molecule this is any of numerous substances that are produced by cells and living organisms biomolecules have a wide range of sizes and structures and perform a vast array of functions all of our biomolecules are classified into four groups we have carbohydrates lipids nucleic acids and proteins each of these classes have different structures and functions all living organisms require several compounds to continue to live we call these compounds biomolecules all of these biomolecules are organic which means that they contain carbon carbon has four valence electrons which means this element forms strong covalent bonds between many other elements and carbon is the most versatile and the most predominant element of life biomolecules is made from linking of small subunits called monomers so what is monomer monomer is the smallest functioning unit of a biomolecule mono means one when there are two monomers together we get a timer dai means two and once several monomers are put together we get a polymer poly means many molecules are either inorganic compounds or organic compounds organic has carbon while inorganic has no carbon under the inorganic compounds we have minerals water and gases under organic we have carbohydrates lipids amino acids proteins enzymes nucleotides nucleic acids and vitamins biomolecules are either micromolecules or macromolecules in biology a micromolecule refers to a molecule of relatively small size and low molecular weight as opposed to a macro molecule which is large and with greater molecular weight under micro molecules we have minerals water gasses sugars amino acids and nucleotides and macromolecules have carbohydrates lipids are fats proteins and nucleic acids all of the major macromolecule classes are similar in that they are large polymers that are assembled from small repeating monomer subunits what are the classification of biomolecules as you can see we have carbohydrates proteins lipids and nucleic acids let us discuss first the carbohydrates carbohydrates are also known as saccharides or carbs the term carbohydrate is derived from the french term hydrate carbonate it means a hydrate of carbon carbohydrates provide energy for the body each gram of carbohydrates provides four calories the body breaks carbohydrates down into glucose which is the primary energy source for the brain and muscles carbohydrates can be represented by the stoichiometric formula which is ch2on where n is the number of carbons in the molecule in other words this is the ratio of carbon to hydrogen to oxygen and that is one is to two is to one one four carbon two for hydrogen and one for oxygen and that is for carbohydrate molecules living organisms use carbohydrates as accessible energy to fuel cellular reactions here are the functions of carbohydrates number one they are the most abundant dietary source of energy and each gram of carbohydrates provide four calories number two carbohydrates along with being the chief energy source in many animals are instant sources of energy glucose is broken down by glycolysis or krebs cycle to yield atp it stands for adenosine triphosphate number three stored carbohydrates act as an energy source instead of proteins number four carbohydrates are intermediates in the biosynthesis of fats and proteins number five carbohydrates aid in the regulation of nerve tissue and the energy source for the brain number six in animals they are an important constituent of connective tissues and the last one carbohydrates that are rich in fiber content help to prevent constipation carbohydrates may be classified into the following monosaccharides disaccharide and polysaccharides let us discuss monosaccharides this is from the prefix mono which means one monosaccharide is the simplest sugar and the basic subunit of a carbohydrate these compounds are white solids at room temperature the most common monosaccharides are glucose this is also known as dextrose one of a group of carbohydrates known as simple sugars next is fructose or in other terms liviulus this is a sugar from fruits the last one is kalakuza this is a sugar in milk the next classification of carbohydrates is disaccharides disaccharides consist of two monosaccharides that are chemically combined the sugar we use to sweeten coffee is a disaccharide it is also known as sucrose or table sugar it is also called as cane sugar this is the sugar found in sugar cane or sugar beet sucrose is the most abundant among naturally occurring sugars it is the important source of dietary carbohydrates and this is made up of glucose and fructose another important disaccharide is lactose or milk sugar lactose is made up of a sugar called galactose and glucose soaring of milk is due to conversion of lactose to lactic acid when two glucose molecules are combined maltose is formed maltose or malt sugar is an intermidget in the intestinal digestion of glycogen and starch and is found in germinating grains next is polysaccharides polysaccharides is also called as glycans this is a complex carbohydrates polysaccharides are polymers containing numerous monosaccharide monomers it means that polysaccharides are large molecules that are made up of many smaller units that are joined together there are three common polysaccharides we have starch glycogen and cellulose starch is the cheap storage form of carbohydrates in plants and this is the most important source of carbohydrate in human nutrition a starch molecule is a polysaccharide assembled from the simple sugar glucose take note that plants make starch next is glycogen glycogen is a polysaccharide that is similar to starch because it is also composed of alpha glucose units it differs from starch since glycogen shows a higher degree of branching and is a polysaccharide that is made by animals glycogen is the major carbohydrate storage form in animals and corresponds to starch in plants it occurs mainly in liver up to six to eight percent what weight and muscle where it rarely exceeds one percent of wet weight the last one is cellulose cellulose are the basic component of plant people cannot digest cellulose but when we eat rich in fiber which is cellulose it speeds the movement of food through the digestive tracts this are the chemical structure of starch glycogen and cellulose let us discuss another category of biomolecules which is proteins proteins are also known as polypeptides proteins are large complex molecules that play many critical roles in the body they do most of the work in cells and are required for the structure function and regulation of the body's tissues and organs proteins are polymers of amino acids they have many functions in the body one of which is found as structural materials in hair nails and connective tissues proteins are made up of the elements carbon hydrogen oxygen nitrogen and sulfur proteins function as enzymes pigments and steroid hormones enzymes are proteins that act as biological catalysts egg white fish meat and cheese are foods rich in proteins they are the second most common molecules found in the human body and make up about 10 to 20 percent of the mass of a cell again proteins serve many vital functions in the body such as structural support enzymes which is the speeding up of chemical reactions next is transport of molecules next is fighting infection and many more amino acids are the building blocks of proteins of the 20 amino acids found in human protein only 11 can be synthesized by the body and 9 have to be supplied by the foods we eat these 9 amino acids are also called essential amino acids adults only need to obtain eight of them such as villi isobuccine diocene lysine methionine phenylalanine trionene and tryptophan the ninth amino acid is histidine this is only essential for infants your body doesn't store amino acids so it needs a regular daily supply of this essential building blocks the next one is non-essential amino acids non-essential is a slightly misleading label because this amino acids actually feel essential roles but since they are synthesized by your body they are not an essential part of your diet the null essential amino acids are alanine asparagine and aspartate of the 11 non-essential amino acids eight are called conditional amino acids such as arginine glutamine tyrosine cysteine glycine proline serine and ornithine next is lipids lipids is the chief concentrated storage form of allergy forming about 3.5 of the cell content lipids are also found in hormones and cell membrane components lipids are organic substances relatively insoluble in water but soluble in organic solvents such as alcohol oily and fatty foods tend to leave stains upon contact right this is why we can use brown paper to detect fats lipids are water insoluble molecules because they are hydrophobic or water fearing that are composed of carbon hydrogen and oxygen that is why all lipids repel water due to how hydrophobic they are this means that they do not bond to water molecules let us discuss the functions of lipids aside from carbohydrates lipids are another class of biomolecules that have the job of storing energy for later use this feature of lipids allows our body to use them as waterproof barriers and as biological membranes lipids act as a chemical messenger or steroid hormone and the last one lipids protect the internal organs and serve as insulating materials the common lipids are fatty acids triglycerides steroids and waxes fatty acids are carboxylic acids or organic acid usually with long aliphatic nails or long chains either unsaturated or saturated saturated fatty acid is indicated when there is a lack of carbon to carbon double bonds the saturated fatty acids have higher melting points compared to unsaturated acids of the corresponding size due to their ability to pack their molecules together thus leading to a straight rod-like shape and saturated fats tend to be solid at room temperature unsaturated fatty acid is indicated when a fatty acid has more than one double bond and they tend to be liquid at room temperature the most abundant of the lipids are the fats and oils this is also called triglycerides fats and oils are triglycerides that come from the combinations of glycerol and three fatty acids fats are solid at room temperature and contain saturated fatty acids take note that all saturated hydrocarbons contain single bonds and are produced only by animals oils are liquid at room temperature and contain unsaturated fatty acids take note that all unsaturated hydrocarbons contain one or more double bonds and are produced by plants steroids are another class of lipids whose molecules are composed of few strings of atoms steroids are vital as hormones which are chemical signals used in the body the most important steroid is cholesterol but excessive levels of cholesterol in the blood can lead to deposits and the arteries of the heart waxes waxes are lipids that come from the combinations of a long chain alcohol and a fatty acid waxes are found almost everywhere fruits and leaves of many plants possess waxy coatings that can safeguard them from small predators and dehydration fur of a few animals and the feathers of birds possess same coatings serving as water repellents carnauba wax is known for its water resistance and toughness here are some examples of waxes number one beeswax this is the secretion of abdominal glands of worker honeybees next is lanolin or wool fat this is the secretion of cutaneous glands and obtained from the wound of sheep the third one sebum this is the secretion of sebaceous glands of skin the fourth one is ceramide this is a soft and brownish waxy secretion of the glands in the external auditory canal this is also called as earwax the fifth one is plant wax this is a coating formed on the plant organs to prevent transpiration the last one is paraffin wax this is a translucent waxy substance obtained from petroleum the last major category of biomolecules is nucleic acid nucleic acids are the genetic material of the cell and are composed of recurring monomeric units called nucleotides nucleic acids are biomolecules that contain the blueprints for making proteins nucleic acids also transmit genetic information to the next generation nucleic acids are molecules that code for hereditary traits by controlling the production of protein like proteins nucleic acids are long chains of polymers consisting of simpler units or monomers we all know that nucleic acids are the genetic material of the cell and are composed of recurring monomeric units called nucleotides each nucleotide is composed of three principal components what are those the first one is five carbon pentose sugar which is the pentagon in the diagram next is phosphate group the circle one the last one is nitrogenous base the rectangle one there are two kinds of nucleic acids such as dna or dioxyribonucleic acid and rna or ribonucleic acid dna found mainly in the cell nuclei contains the genetic information that codes for the sequences of amino acids in proteins rna is found in many places in the cell and carries out the synthesis of proteins the monomers of nucleic acids are nucleotides they are made up of three parts again we have e5 carbon sugar which is pentose a phosphate glue and a ring sheet based containing nitrogen or the nitrogenous base nucleic acids contain carbon hydrogen oxygen nitrogen and phosphorus as you can see nucleotides is a monomer but if there are a long chains of nucleotides it will form nucleic acid and that is polymer we all know that nucleic acid can be dna or rna and that would be all i hope you learned something about the topic and thank you so much for watching keep safe [Music] you