Biomolecules in 15 minute 🔥| NEET 2026 One Shot | Dr. Yokesh Arul

Added: 2026-05-05

[00:00:00]Hello doctors, I'm Dr. from GB now exam so I'm pretty sure you guys will be revising right now my telegram group may MCQs plans religiously follow Alana you will get the jump in scores which you are expecting and recently YouTube pura strategy video important topics which share just follow those now let's start all carbon compounds that are obtained from living tissues are called biomolecules.

[00:00:30]Now how to analyze chemical composition the whole two experiments so we take living tissue for example vegetable or a piece of liver we grind it in trichloroacetic acid is about the thick slurry is obtained and strain and we get two fractions one is acid soluble pool your filtrate or acid insoluble pool retained Joe Cooper at that now acid soluble pool may organic compounds are found and inorganic compounds are found example sulfate phosphate but acid insoluble pool. Made the return then we have four types of organic compounds proteins nucleic acids lipids and polysaccharides now experiment number two dry a small amount of living tissue for example leaf or liver salad evaporated and the remaining dry weight is called Jalal now the carbon compounds get oxidized to gas to form CO2 and H2O vapors the remaining ash we find inorganic elements for example calcium and magnesium and many more now elemental. Analysis this gives elemental composition of living tissues in the form of hydrogen oxygen chloride and carbon now analysis of these compounds is they have a rough idea organic and inorganic in the living tissues now amino acids they are organic compounds also known as alpha amino acids so they have an amino group and an acidic group which act as a substituent on the same carbon which is the alpha carbon structure a substituted methanes physical and chemical properties. essentially of amino carboxyl and our group analyzable nature of NH2 and COH group is present now what are the four substituent groups occupying the four valency position of carbon H H2N COH and our group variable and this defines the type of amino acid now the our group is hydrogen you will make a glycine if it's methyl group will make a alanine if it's hydroxymethyl will make serine now amino acids do form exist that. In acidic pH it is in cationic in alkaline pH it is anionic now when an amino acid has positive and negative charge we call this zwitterion form all the doctors now lipids lipids can be simple fatty acids it contains a carboxyl group plus an R group which is variable now two types saturated unsaturated in saturated they'll have a single CC bond whereas in unsaturated they'll have one or more double CC bonds now glutamic acid is a acidic amino acid lysine is a basic amino acid valine. Is neutral and tyrosine phenylalanine tryptophan are aromatic amino acids now our groups one carbon say 19 carbons now three types simple derived and compound now simple two types glycerol aka trihydroxypropane and glycerides which have fatty acids esterified with glycerol example mono glycerides diglycerides and triglycerides derived may we have cholesterol Now compound or complex may they possess some additional compounds example phosphorus or glucose example phospholipid lecithin which is found in cell membrane oils have lower melting point in winters hence they remain in oil form example gingelly oil all the doctors now let's see primary and secondary metabolite now primary may they have identifiable functions they play known role in normal physiological process. And all are found in animal tissues they are found in plant fungal and microbial cells now here are some secondary metabolites important table pigments carotenoids and anthocyanins alkaloids morphine codeine terpenoids example monoterpenes and diterpenes essential oils lemon grass oil toxins abrin and ricin lectins example concavalin a drugs example vinblastine and curcumin polymeric substances example rubber gum and cellulose. Now biomolecules two types micro molecules and macro molecules aka biomacromolecules now micro may compounds are found in acid soluble pool they weigh around 18 to 800 Dalton or less than thousand Daltons because micro now macro may compounds are found in acid insoluble fraction and they weigh more than 10,000 Daltons exception lipids now molecules in insoluble form fraction are also known as polymeric substances exception lipids or lipids.

[00:04:59]Is the exception and it plays a role in missile formation all the doctors now acid soluble pool represents the cytoplasmic composition important whereas the acid insoluble fraction it represents macro molecules from cytoplasm and organelle now though lipid being an exception it comes under macro molecules important because they are present only as such but are also arranged in structures. Like cell membranes and other membranes now on grinding tissues cell structure disrupts the cell membrane break into pieces and form vesicles which are not water soluble now these membrane fragments and get separated with insoluble pool so lipids are not strictly macro molecules now look at the average composition of cells in our body water 70 to 90 which is about protein 10 to 15 which is about carbs 3% which is about lipids 2% which is about nucleic acid 5 to 7. Which is about ions just 1% now decreasing order may place which is water proteins nucleic acids carbs lipids and ions now it's a mnemonic heavy uncle all the doctors now let's go to proteins and polysaccharides which is my favorite part proteins are polypeptides it is a linear chain of amino acids linked by peptide bonds now because amino acids are of 20 types proteins are heteropolymers amino acids two types essential non-essential essential is because they can be provided only by. The diet whereas non-essential they are prepared within our body to essential now collagen is the most abundant protein in animal world Rubisco ribulose-1,5-bisphosphate carboxylase and oxygenase this is the most abundant protein in whole of biosphere all the doctors now what is polysaccharides they are long chain of sugars two types heteropolysaccharides homopolysaccharides now it's me what they are simple complex. Simple example cellulose and starch complex now amino sugars are chemically modified sugars are present example n-acetylgalactosamine or glucosamine exoskeleton of arthropods with example is chitin wall all the doctors example cellulose is a homopolymer of glucose whereas starch is a storage of energy in plants it is also a homopolymer of glucose now starch plus I2 is blue in color glycogen is present in animals. Inulin is a polymer of fructose now in the polysaccharide chain the right end is the reducing end remember right reducing left end is the non-reducing end it has branches in the form of a cartload now starch forms helical secondary structures and holds the I2 molecules in helices cellulose doesn't have helices so it cannot hold I2 all the doctors now nucleic acids these are polynucleotides nucleotides are building. Blocks now nucleotides consist of nucleoside and phosphate group now this nucleoside it has heterocyclic rings and monosaccharide or sugar now heterocyclic rings they are nitrogenous bases adenine guanine AG.

[00:08:13]Substituted purines whereas substituted pyrimidines are CTU.

[00:08:19]Cytosine.

[00:08:20]Thymine and uracil and thymine thiamine yeah.

[00:08:27]All the doctors monosaccharide or sugar is ribose which is a pentose sugar and deoxyribose now nucleic acids with ribose are called as RNA ribonucleic acid whereas nucleic acid with two deoxyribose are DNA which is known as deoxyribonucleic acid now doctors the diagram this is adenine which is a purine this is adenosine which has adenine group and this is adenylic acid and this is a nitrogen base which is pyrimidine. Now this is uridine which is a nucleoside now let's look at this also this is glucose and this is ribose all the doctors now let's see the structure of proteins protein structure is at four levels primary secondary tertiary quaternary now primary gives positional confirmation of an amino acid or sequence of amino acids left and make out there first amino acids which is the end terminal right and make out there last amino acid which is the C terminal now secondary it has two structures alpha helix beta pleated sheet. May 2 literally charge the bucket alpha helix some portions of the protein thread are arranged in the form of helix whereas beta pleated some regions are folded in beta pleated sheets all the doctors now tertiary the protein chain is folded upon itself like a hollow wooden ball it has a three-dimensional view and it is absolutely necessary for biological activities of protein all the doctors now quaternary now proteins are made of more than one polypeptide change now the arrangement of these individual folded polypeptide subunits with each other. Now, the adult hemoglobin has four subunits, two alpha type and two beta type.

[00:10:06]All right, doctors. Now, enzymes. Now, almost all enzymes are proteins, whereas ribozyme, the nucleic acid act as an enzyme. Now, enzymes show primary, secondary, and tertiary structure. Now, equal to the active site. It is a crevice or a pocket into which the substrate fits. Now, what is a catalyst?

[00:10:23]Two types you would have enzyme catalyst or inorganic catalyst. Enzyme catalyst gets damaged at higher temperature above 40° C.

[00:10:31]Exception, enzymes isolated from thermophilic organisms. You can have it to give me the obviously it looks safe later. These enzymes retain the catalytic power even at 80 to 90° C.

[00:10:45]Now, inorganic catalyst work efficiently even at high temperatures and higher pressures. All right, doctors. Now, let's see biochemical reaction and enzymes. Now, catalyzed reaction rates vastly are higher than non-catalyzed ones.

[00:10:59]Now, reactions where there's a physical change in the state or matter. Now, the rate of physical or chemical process refers to the amount of product formed per unit time. So, rate [clears throat] is equal to delta P by delta T, which is time. Now, it can also be called as velocity if the direction is specified.

[00:11:17]Now, this is influenced by temperature.

[00:11:20]So, rate doubles or is decreased by half for every 10° C change in either direction. Now, for example, RBC has a reaction CO2 + H2O in the presence of carbonic anhydrase, which is found in the cytoplasm, forms carbonic acid. Now, in the absence of enzyme, 200 molecules of H2CO3 is formed per hour. But, in the presence of enzyme, 600,000 molecules per second is formed. The reaction rate is increased by 10 million times. And this enzyme is found in the cytoplasm.

[00:11:55]Now, metabolic pathway a multi-step chemical reaction where each step is catalyzed by the same enzyme or different enzyme. So, this is a multi-step pathway. Now, look at this.

[00:12:05]Now, glucose forms two pyruvic acid via glycolysis. Here, 10 different enzymes through 10 different catalyzed metabolic reactions occur. All right, doctors.

[00:12:14]Now, let's look at the mechanism of action. Now, substrate diffuses towards the active site of enzyme. There is formation of enzyme-substrate complex.

[00:12:22]There is a transient state of structure of substrate formed. The bond gets broken and the product is released from active site. Now, look at the diagram.

[00:12:29]Substrate, active site, so you have an enzyme-substrate complex which is transient and you have enzyme-product complex is formed. Then, the enzyme and product is detached. Now, the pathway of substrate to the product transformation must go through the transient state structure. You have both important there. Now, there could be many altered substrate states between the substrate and the product. All intermediate structures are unstable. Now, the formation of enzyme-substrate complex is essential for catalysis. Now, substrate diffuses towards each states between substrate and product. All intermediate structures are unstable. You have both important there. It's really repeat color down. Now, doctors stability is related to energy status of the molecule. There is a energy level difference between substrate and product. Now, look at this. This is a relation of energy. This is the progress of reaction. I mean you have substrate or you have transient state. Now, this is activation of energy with enzyme common energy level. Now, this is activation energy without enzyme. So, that energy level. Right? Now, what is exothermic reaction? If the product is at lower level than substrate, no external energy is supplied. Now, irrespective of exothermic or endothermic reaction, substrate has to go through higher energy state. Now, what is activation energy? The difference in average energy content of substrate from that of transition state.

[00:13:49]Now, as I explained in this diagram, energy decreases activation energy to catalyze the reaction. Now, what are the factors affecting enzyme activity?

[00:13:58]Enzyme activity can be affected by change in condition which can alter the tertiary structure of protein. Now, number one is temperature and pH. They function in narrow range of temperature and pH. Highest activity at optimum temperature at pH. Optimum temperature pH is the activity highest rate. Now, low temperature enzyme activity is temporarily in inactive state. High temperature may destroy the enzyme activity because the proteins are denatured.

[00:14:24]So, that's why optimum temperature may they have highest activity. Number two is concentration of substrate. When there is increase in substrate concentration, the velocity of the reaction rises at first, but then when the reaction reaches max, the velocity further it does not rise with substrate because the enzyme molecules get saturated.

[00:14:43]Point to that saturated.

[00:14:46]Now, inhibition. Chemicals which bind to the enzyme and shuts off the enzyme activity process is called inhibition.

[00:14:53]Now, example inhibition of succinic dehydrogenase by malonate. Now, competitive inhibitors. Inhibitors which closely resemble the substrate in the same in molecular structure and inhibits the enzyme activity by binding to the substrate binding site of the enzyme.

[00:15:09]All right, doctors. Now, malonate resembles succinate in structure.

[00:15:13]Such competitive inhibitors are often used in control of bacterial pathogen.

[00:15:18]Now, let's look at this chart quickly.

[00:15:19]Catalytic cycle of an enzyme action can be described as substrate binds to active site of an enzyme fitting into active site. Now, the binding of substrate induces the enzyme to alter the shape, okay? And it fits more tightly around the substrate. Now, the active site of enzyme in close proximity of substrate breaks the chemical bonds of the substrate and the new enzyme-product complex is formed. Now, the enzyme releases the product of reaction and free enzyme is ready to bind to other molecules. All right, doctors. Now, [clears throat] classification and nomenclature of enzymes. Now, enzymes are classified based on the type of reactions they catalyze and enzymes are divided into six classes, each designated by four-digit code based on subclasses.

[00:16:01]Class one oxidoreductase or dehydrogenase. Enzyme which catalyze oxidoreducto reaction between two substrates. Class two is transferase.

[00:16:10]Enzyme which catalyze transfer of the group other than hydrogen between a pair of substrate. Class three is hydrolase.

[00:16:17]Enzymes catalyzing hydrolysis of ester, ether, peptide, glycosidic, double C and C halide or P and bonds. Class four is lyase. Enzymes catalyzing cleavage of bonds by mechanism other than hydrolysis leaving double bonds. Class five is isomerase. Enzyme catalyzing interconversion of optical, geometric, and positional isomers. Class six is ligase. Enzyme catalyzing linking together of two compounds. Example, enzyme catalyzing joining of CO, CS, PO bonds. Now, what are the cofactors? Now, enzyme is equal to apoenzyme plus cofactors. Apoenzyme proteinaceous and cofactors non-proteinaceous. Now, cofactors bind to the enzyme to make them catalytically active. Catalytic activity is lost if the cofactor is removed. You have both important there.

[00:17:09]Now, let's see cofactors. Prosthetic groups, coenzymes, and metal ions. Now, prosthetic groups. They are organic compounds. They are tightly bound to apoenzyme. Example, in peroxidase and catalase, heme is the prosthetic group.

[00:17:24]It is a part of active site of the enzyme. Now, coenzymes. They are organic compounds. Transient association with apoenzyme which occurs during the course of catalysis. So, they serve as cofactors in a number of different enzyme-catalyzed reactions. Essential chemical components of many coenzymes are actually vitamins.

[00:17:46]Example, coenzyme nicotinamide adenine dinucleotide, which is NAD and NADP contain vitamin niacin. Now, metal ions.

[00:17:55]Coordination bonds are formed with side chains at active site and at the same time form one or more coordination bond with substrate. Example, zinc is a cofactor for the proteolytic enzyme carboxypeptidase.

[00:18:08]All right, doctors. We're done with the chapter. This chapter is also very important.

[00:18:13]Revise and keep listening to it on repeat.

[00:18:17]Doctors, we have very less time for the exam. My Telegram channel may I've shared a very detailed strategy.

[00:18:24]Join I'll catch you over there.