Nucleic acids – DNA and RNA structure

Nucleic acids – DNA and RNA structure

In this video we will study about nucleic acids. Nucleic acids are basically biopolymers, which are made of monomeric units known as nuclotides. We have two important functions for nucleic acids, that is, they hold our genetic information and they perform a variety of other functions that we will discuss later. We have two important types of nucleic acids in our body, the DNA and the RNA. Let’s first try to understand the definition of nucleic acids. So, nucleic acids are biopolymers. “Bio” means that they are synthesized inside biological systems, and they are not synthetically synthesized. They are polymers, which means they are made of repeated units called monomers, which in this case are nucleotides. Now take this example. We have many different types of biopolymers in our body; one of them are the proteins. And most of you know that the proteins are made up of repeated units called amino acids. Similarly, nucleic acids are also important biopolymers in our body. Which are made up of repeated units which are known as nucleotides. The next important thing is to understand the basic structure of a nucleotide, which will help us understand the structure of nucleic acids in detail. Now, this is a simple diagram explaining the structure of a nucleotide. As you can see, the single nucleotide is made up of three important groups: The phosphate, the sugar, and the nitrogenous base, and these groups are attached to one another by bonds, which we will discuss later. To understand the complete structure of a nucleotide, let’s try to understand the structure of these groups one by one. The first is the sugar. The sugar present inside the nucleic acids are five carbon sugars. Now most of you know the sixth carbon sugar present inside the body, and most important of them is the glucose. In chemical nomenclature, all six carbon sugars are called hexoses, the word “hex” meaning “six.” There are different types of hexoses in our body other than glucose like the mannose and galactose Similarly, five carbon sugars are called pentoses, the word “pent” meaning “five.” There are different types of pentoses in our body, but the two important types of pentoses that are present in the nucleic acids are the ribose, and the deoxyribose. but this is a simplified structure of the sugar present inside the nucleotide. Now is you compare this structure with the chemical structure of the ribose and deoxyribose on the right, you can see the structure clearly. We have carbon atoms on each of these corners. Note that the last carbon atom is located outside the ring. We have an oxygen atom at the center topmost position. You can also see in this chemical structure that the carbon atoms are named from one to five in a clockwise direction. So the carbon atom next to the right of the oxygen is called C1, so C2, C3, C4 and C5 C5 is located outside the ring. You can also see in this chemical structure we have different types of functional groups attached to these carbon atoms like the hydroxyl group and the hydrogen atom. The most important of these functional groups, which determine whether the sugar is ribose or deoxyribose are present at the carbon number 2 and the carbon number 3. In the sugar ribose, we have a hydroxyl group that is attached to the carbon number 2. This is the chemical structure of ribose Now, if you compare this structure with the structure of deoxyribose, the only major difference is at carbon number 2 the carbon number 2 contains only a hydrogen atom, and not the hydroxyl group so the resulting sugar is called a deoxyribose. Here, you can see the carbon number 2 in deoxyribose contains only a hydrogen atom, whereas in ribose the carbon number 2 contains a hydroxyl group. You can also tell this by the difference in their names, that the deoxyribose has a prefix “deoxy,” which means the removal of oxygen. The resulting sugar, the deoxyribose, is more stable as compared to ribose because of one less functional group. The deoxyribose is present in DNA and ribose is present in RNA. You can also remember by the starting of DNA which starts with D, so the “deoxyribose” and the RNA which starts with R, so the sugar is the ribose. The next important group we’re studying for the structure of nucleotides is the phosphate group which is this little detail here. The phosphare group consists of a phosphorus atom in the center, to which four oxygen atoms are attached, which are negatively charged. The phosphate group is the same phosphate group which is present in the adenosine triphosphate, the energy-carrying molecule of the body. However, in ATP we have three molecules of phosphate, which are attached to one another by high-energy phospho-ester bonds. The phosphate group is a polar molecule due to the presence of highly ionized oxygen atoms, which impart negative charge to the phosphate group. Now, the third important structure present in the structure of a nucleotide is the nitrogenous base. Nitrogenous bases are basically molecules that contain nitrogen in varying amounts, and they act as a base. Most of you know that the human body contains organic chemicals, which have carbon, hydrogen and oxygen in varying amounts. In nitrogenous bases, nitrogen combines with all of these atoms to form ring-like structures. These molecules are called bases since they can donate electrons to other molecules and form new molecules in this process. The nitrogen combines with all of these other atoms to form ring structures. Now, we can have two different types of ring structures. One where there are single rings, and second, where there are double rings. The single rings are called pyramidines. And the double rings are called purines. We have three different types of pyramidines: the thymine, cytosine, and the uricil. And we have two different types of purines, called adenine, and guanine. In the center you can see the chemical structure of each of these bases. As you can see, the purines, which are the double-ring structures, adenine and guanine. Due to the presence of double rings, these purines are larger as compared to the pyramidines. The thymine, cytosine and uracil all are single-ring structures, and they are smaller as compared to the purines. The difference in the size of these bases is very important, as it helps to bear these bases in the structure of DNA properly, which we’ll study later. So now you know the individual structures which are present in a single nucleotide. Next we will look at how these individual structures bond to each other to form a single nucleotide, and then we will look at how many nucleotides bind to each other to form a chain of nucleotides, which is called a polynucleotide, which can be either DNA or RNA. So, if we take a sugar and name just the important carbons here, which will be carbon number 1 and carbon number 5 and of course you can see that at the carbon number 2 there is only a single hydrogen atom so this sugar will be a deoxyribose. To pair this deoxyribose sugar with this pyramidine ring, the bond formed will be between the N1 of the pyramidine ring and the C1 of the sugar. If you want to go into the details about how these nitrogens are named, you can check the link in the description below for IUPAC nomenclature for the aromatic compounds. Now this bond will be an example of a glycosidic bond, which is a covalent bond which links carbohydrates with other structures. If we have to pair a purine ring at a similar position, the bond formed will be between the N9 of the purine ring. Next, let’s attach the phosphate. The phosphate group attaches with the carbon number 5 of the sugar, and the bond formed is the example of the ester bond which is also a strong covalent bond. So now you know how the three structures in a single nucleotide bind to each other to form one nucleotide. Next, we look at how many nucleotides bind to each other to form a chain of nucleotides called a polynucleotide. You can see basically what happens is that the phosphate group that attaches to the carbon number 5 of the sugar below also forms a bond with the carbon number 3 of the sugar above, and this pattern is repeated again and again. So you can see that the phosphate groups form bonds both above and below the chain of these nucleotides. As a result, a long chain of nucleotides is formed which consists of a sugar-phosphate backbone and in the center we have all these nitrogenous bases, which project from the sugar-phosphate backbone. Now this can be an example of RNA if the sugar present in this example will be a ribose sugar. But if you take a similar strand of polynucleotides and run it in opposite direction then this strand binds with the original strand through hydrogen bonds. Now here comes the rule of complementary base pairing. What complimentary base pairing says is that only adenine forms a hydrogen bond with thymine, and only guanine forms a hydrogen bond with cytosine. This is a universal rule that is applied in the structure of DNA. Here you can see adenine forms a hydrogen bond with thymine, and similarly thymine forms a hydrogen bond with only adenine. In similar case, guanine forms a hydrogen bond with cytosine and vice versa. This is the basic structure of DNA and you can compare this with a step ladder structure of DNA. You can see that the supports of the ladder in red are basically representing the sugar-phosphate backbone and the rungs of the ladder represent the nitrogenous bases that are forming hydrogen bonds with each other. Of course, the original structure of DNA is that of a double helix, so you you can compare the structure with a double helix, where the helices of the structure represent the sugar-phosphate backbone, and in the center you can see the red lines which represent the different nitrogenous bases that are forming bonds with each other. So this was an introductory video explaining the structure of nucleic acids. In subsequent videos, we will study in detail the structure of DNA, the structure of RNA, DNA replication, transcription, translation, and many other topics. Make sure to subscribe to our channel for further upcoming videos, and also make sure to like our facebook page for all the notifications and flash cards. Thank you so much for watching.



  • star shine

    I really hope i had discoverd this channel before….😥
    Really nice explanations👍

  • Mir Showkat

    Thanks sir really helpful for me
    It is complicated topic
    But you gave nice explanation
    May ALLAH bless u always

  • Sangita Sutradhar

    Worst video channel

  • Sangita Sutradhar

    Is everyone mad.

  • Uday Dadke

    Very nice explanation👌


    Superbly explained.


    Tnq for explaining such a hard topic 🙏🙏🙏

  • satyaprakash rajpoot

    Thank you very very very very much sir
    I understood it very well
    Thank you so much

  • Gitesh Rautwar

    Really well…..very clear..👍

  • احمد علي عبدالرحمن على عبدالرحمن

    Many thank for you its very excited and recommended

  • Zul O Curran

    👍👍clarity is power.

  • Simran Vidyarthi

    Why you stop making videos , over biochemistry topics ?

  • aslo alxive

    good explanation

  • Esther Antony

    Very good explanation, I found it very helpful to understand and learn. Image representations are very impressive

  • Abhijeet Kumar

    Thank you Sir….!
    I am not so much impressed as today…..l can't express my obligation to you….
    Very very thankful….Sir!

  • karishma Kumari

    Thank u so much sir…..keep making such videos

  • Ali Akdogan Denmark

    Hi , tanks for an amazing video. Først time in my life I understand DNA and RNA. I hobe you will make more video about biology.

  • Gabriel Moraes

    Great video! Thanks for sharing! Excellent explanation!

  • Yu Katsuragii

    Lol. I and my crush are sleeping every time our professor is having a lecture. because we can't relate because she is making it complicated. I owe you one, my friend. Now I understand a lot of things about Nucleic acids.

  • sanjivani patil

    i am very grateful to u for all the videos u make.

  • Thanos •

    Thanks. Thanks. Thanks. Thank you very much. Thank you!😊

  • Mohammad Sayem Farrukh

    👍👍 Well done

  • Ridhima Rai

    Thankyou for makings this video it iw so helpful 🙌🙌✨:)

  • Md Rashid

    Sir nice video. But i have question that why DNA is present in form of ANTI PARALLEL direction. Please give me answer. Thanks

  • Ponkti Addrita


  • zartasha khan

    awesome method to explain

  • Aidzah Athirah

    Tbrh this video explains better than my lecture is

  • Anđela Morana


  • Vimbai Ngorima

    Thank you………..sooo much

  • Aniket Gawande

    Lifetime memorable concept…
    Thank you sir

  • Hifrax Yonardhi

    you really simplified this, man…

  • pallavi gupta

    Thanks a lot ,awesome👍🏻👍🏻

  • Meenakshi Nagar

    Awesome cleared my doubts

  • Sana Arain

    Very helpful video👌thank u so much sir

  • Saba Rehana

    what an understanding of nucleicacids this man has!!!!its really medsimplified😊😊😊thanks a lot sir☺

  • Navu Kaur

    U are best
    Thank you so much

  • Light of the world is jesus

    Nice ,you explain very clearly

  • Kashish Baesla

    damn … uhh made this topic a lot easier for me …….thnxx a lott !!!! @MEDSimplified – the best channel for studies

  • Kashish Baesla

    sir please make vedio on full biomolecules chapter

  • Shivani Agarwal

    Best ever video… For studying biology…. Great work Sir…👏

  • Geovany Lizarraga

    wow, you explained that very well, learned this in 10 min and couldn't comprehend it in class for 16 weeks. It's the visuals.

  • Chowla Rishitha

    Really osm explainton understood very perfectly,Ur fantastic

  • Ashwini H

    Uh did it!!!!!!!

  • Sidra Anwar

    thank u so much

  • MooDy Girl

    What a video… thank u sir👏

  • Solomon O Samuel

    Very complicated topic being dismantled into tiny basic pieces!!! Thanks for a perfect piece of work you’ve done here

  • juhi yadav

    Best explanation

  • Ashutosh Patel

    The best video at all



  • Salma Khalid


  • Veronika saikia

    This video is really helpful ☺☺☺☺

  • Deepak Thakur

    So nice

  • Ratna Upadhyay

    Thank you mister 🇳🇵🇳🇵🇳🇵🇳🇵🇳🇵

  • nawmee rahman

    i love the presentation and contents of this tutorial.simply and nicely explained.

  • Omar

    u made it so easy thank you so much ur genius

  • Biff Danielson

    I wish I lived in a country that emphasized education as much as India does

  • Mahfuza Kajol

    Really nice

  • learn biology

    u people are great. thanks

  • Krisha

    Plz make a video on lac operon

  • Kiyana Rostami

    It was really instructive 👍

  • Vikash Kumar Thakur

    Bohot accha pdhaya bhai

  • Genica de Lara

    Thank you so much. THIS HELPS ME A LOT!

  • umema nadeem


  • Mubasher Ahmed


  • Michael Harris

    Is there exchanges of electrons between them, is that the bonding. And do the rungs of the latter exchange any electron between each other rather than just across the rung. Sorry for asking questions on an amazing video. I suppose I want to know why do they line up vertically also, rather than just across.

  • Harsh wardhan

    Amazing voice and teaching ability which give a pleasure to mind and how simple u made topics un explainable.

  • bhava dharini

    Awesome…. thank u sir ,pls upload more videos about nucleic acid

  • Dhurai Raj

    superb explanation… no one can beat u in teaching such weightage chapters…awesome..

  • A. More

    Why don't all teachers explain like this.
    This video made me feel the DNA👍😲👍👍 Great job dude!!

  • Carol Jackson

    Thank you so much for you help.

  • Its Mae Preciously

    Ohhh Thankyou so much for this tutorial lol.. You helped me a lot!

  • Lilly Lilly

    bro excellent .u made me this chapter a 'a piece of cake'…..thank u…pls post more & more videos in future…

  • Imrana Sahar

    i had studies so many books … but was still confused about the structure of DNA … idk who are you , but i prayed for u teacher 😍😍

  • stranger boy

    You are legend .subscribed 👏👏👏

  • stranger boy

    I am thankful to you sir ..your english is so clear every single person can understand it .
    This topic is now clear to me .

  • Jona Reigns

    Great video. Just can't understand some of the words his saying because of his accent. But thanks!

  • komling tayeng

    Sir, I still have a doubts, where is uracil in hydrogen bond??

  • Sadaf Khan


  • Anmol Gupta

    Just amazing

  • Bendy 20

    Kudos to you for explaining this

  • Aml Noor

    Brilliant introductory site.Voice quality & speed great, explain,good points…
    JaZakAllah, sir for help out!!!💝

  • Surya Singh

    your video is superb andi request you to give us more topic on this chapter and help us to make bio interasting

  • salai kalanidhi

    You are really awesome…. Transcription translation replication Structure and everything just simply superb… Well explained… Thanks a lot. Really enjoyed

  • عبدالله خليفة

    Man you just unbeleavable


    I too studied this structure, but they forgot to teach me about the soup.

  • slehar

    Wow! That was awesome! Great presentation of an otherwise deeply obscure topic! Thank you!

  • Ken Jackson

    Very good presentation! But did all this organization come about by an unguided process? How?

  • Truely Blessed

    He went innnnn great video!!!! #subcribed !!!!

  • Shubham singh

    Very nice explanation 😊

  • Ibrar Shah swaty

    Tnx u for sharing

  • Dipanshu Singh rawat


  • Bushra Marri

    Awesome explanation 👏👏👏

  • Maryam Atif Qureshi

    1)Nucleic acids- bio polymers are made up chains of monomers
    2)Two functions of nucleic acids: hold genetic information and perform variety of other functions
    3)Two types of Nucleic acid: DNA and RNA
    4)DNA: Deoxyribonucleic acid
    5)RNA: Ribonucleic acid
    6)Proteins are biopolymers and are made up of amino acids
    7)Nucleic acids are also biopolymers which are made up of nucleotides
    8)3 parts of the Nucleotide
    1-Phosphate group
    3-Nitrogenous base
    9)5 Carbon sugars is called Pentose
    10)6 Carbon sugars is called a hexose
    11)Deoxyribose (DNA) is more stable than Ribose (RNA)
    12)Two main types of Pentoses:
    14)The phosphate group is a polar molecule which contains highly ionises oxygen atoms.
    15)Nitrogenous base: molecules that contain nitrogen and act as an base
    16)Nitrogenous base contains: Carbon(C),Hydrogen(H),Oxygen(O) and Nitrogen(N)
    17)Nitrogen combines with all of these atoms to form ring structures
    -single ring
    -3 types: Thymine, Cytosine and uracil
    -smaller than Purines
    -Double rings
    -2 types: Adenine and Guanine
    -Larger than Pyrimidines
    18)Many nucleotides bind to each other to form a chain of nucleotides called polynucleotides
    19)The long chain of nucleotides consists of a sugar phosphate backbone and nitrogenous bases
    20)Glycocidic bonds are covalent bonds which link carbohydrates with other structures
    21)Ester bonds is charecterised by a carbon bound to 3 other atoms
    1*single bond to carbon bond
    2*single bond to oxygen bond
    3*double bond to oxygen
    22)THE COMPLEMENTARY BASE PAIRING RULE: only Adenine forms a hydrogen bond with Thymine and only Guanine forms a hydrogen bond with Cytosine

  • Swetha swetha


  • Huda Mohd Apandi

    im really thankful this video exist , i really understand your explaination

  • Rushikesh Kirtikar

    OMG! It was Great explanation. But why did you make our body so complex? Can't you keep it simple so that we would have understood it easily?

  • Francis Akinnola


  • joel katai

    wow, decent work there……….

  • Jaime Perez

    Most excellent video. Wonderfully made and needs to be seen by the whole world. People who teach must be shown this video so they can learn how teaching should N must be done throughout the world!

  • shivam sharma

    Jayda jaldi hai kya

  • Your email address will not be published. Required fields are marked *