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Which of the following are the salient features of the Double-helix structure of DNA? 1. The two chains have antiparallel polarity. 2. The bases in two strands are paired through hydrogen bonds (H-bonds) forming base pairs (bp).  3. The two chains are coiled in a right-handed fashion. Select the correct answer using the code given below.

Which of the following are the salient features of the Double-helix structure of DNA? 1. The two chains have antiparallel polarity. 2. The bases in two strands are paired through hydrogen bonds (H-bonds) forming base pairs (bp).  3. The two chains are coiled in a right-handed fashion. Select the correct answer using the code given below. Correct Answer 1, 2 and 3 

The correct answer is 1, 2, and 3.

Key Points

The salient features of the Double-helix structure of DNA are as follows:

  • It is made of two polynucleotide chains, where the backbone is constituted by sugar-phosphate, and the bases project inside.
  • The two chains have antiparallel polarity. It means, if one chain has the polarity 5'à3', the other has 3'à5'. Hence statement 1 is correct.
  • The bases in two strands are paired through hydrogen bonds (H-bonds) forming base pairs (bp). Hence statement 2 is correct.
    • Adenine forms two hydrogen bonds with Thymine from the opposite strand and vice-versa.
    • Similarly, Guanine is bonded with Cytosine with three H-bonds.
    • As a result, always a purine comes opposite to a pyrimidine.
    • This generates an approximately uniform distance between the two strands of the helix.
  • The two chains are coiled in a right-handed fashion. Hence statement 3 is correct.
  • The pitch of the helix is 3.4 nm (a nanometre is one-billionth of a metre, that is 10-9 m) and there is roughly 10 bp in each turn. Consequently, the distance between a bp in a helix is approximately 0.34 nm.
  • The plane of one base pair stacks over the other in a double helix. This, in addition to H-bonds, confers the stability of the helical structure.
  • The proposition of a double helix structure for DNA and its simplicity in explaining the genetic implication became revolutionary.
  • Francis Crick proposed the Central dogma in molecular biology, which states that genetic information flows from DNA to RNA to Protein.
  • In some viruses the flow of information is in the reverse direction, that is, from RNA to DNA.

Related Questions

Consider the following statements and choose the correct answer:
1. Adenine pairs with thymine (A : T) and guanine with cytosine $$\left( {G \vdots C} \right)$$
2. Adenine and thymine are joined by three hydrogen bonds through atoms
3. Guanine and cytosine are joined by two hydrogen bonds through atoms
4. The weak hydrogen bonding enables the two strands of the DNA to separate during replication
Which of the following statements are correct? 1. The DNA Technology (Use and Application) Regulation Bill, 2019 provides for the regulation of use of DNA technology for establishing the identity of certain persons. 2. DNA is made up of 26 pairs of chromosomes and provides instructions for building an entire organism and proteins. 3. DNA is composed of two chains, which coil around each other to form a double helix carrying the genetic instructions used in the growth. 4. Under the Bill, DNA profiling is allowed only in respect of criminal matters. Select the correct answer using the code given below:
Consider the following statements regarding DNA replication and choose the correct answer:
1. The very first requirement of DNA synthesis is the presence of a template or plan along which the new strand is to be constructed
2. The second requirement is of a DNA-dependent-DNA polymerase or simply DNA polymerase enzyme
3. A DNA Pol cannot join two free nucleotides; one of them must be anchored by hydrogen bonds to a DNA strand
4. Replication takes place bidirectionally
Which of the following statements about DNA is/are correct? 1) DNA is the hereditary material of all living organisms. 2) All segments of DNA code for the synthesis of proteins. 3) Nuclear DNA is double helical with two nucleotide chains that run anti-parallel. 4) DNA is also found in mitochondria. Select the correct answer using the code given below:
In the following passage some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives. Indias motto has been Vasudeva Kutumbakam or that the whole world is _____ community. There are a _____ of pillars upon which Indias policy of living in peace with and _____ peace among nations of the world rests. Policies of non-alignment, peaceful co-existence, economic and cultural cooperation disarmament and peaceful _____ of nuclear energy, _____ of International disputes through negotiations and peaceful means are some of the salient features that give credence to Indias commitment to world peace. _____ of International disputes through negotiations and peaceful means are some of the salient features
Which of the following statements about DNA is/are correct?
1. DNA is the hereditary material of all living organisms.
2. All segments of DNA code for synthesis of proteins.
3. Nuclear DNA is double helical with two nucleotide chains which run anti-parallel.
4. DNA is also found in mitochondria.
Select the correct answer:
Consider the following statements regarding Genome Sequencing: 1. Genome sequencing is figuring out the order of DNA nucleotides, or bases, in a genome—the order of Adenine, Cytosine, Guanines, and Thymine that make up an organism's DNA. 2. Human genome is made up of 46 chromosome pairs with a total of about 3 billion DNA base pairs. 3. There are 24 distinct human chromosomes: 22 autosomal chromosomes, plus the sex-determining X and Y chromosomes. Which of the statements given above is/are correct?
With reference to 'IFC Masala Bonds' sometimes seen in the news, which of the statements given below is/are correct? 1. The International Finance Corporation, which offers these bonds, is an arm of the World Bank. 2. They are the rupee-denominated bonds and are a source of debt financing for the public and private sector. Select the correct answer using the code given below.
In a DNA double helix the bases are held together by hydrogen bonds. These hydrogen bonds are _________ 
interface Base{ boolean m1 (); byte m2(short s);}

which two code fragments will compile?
1. interface Base2 implements Base {}2. abstract class Class2 extends Base { public boolean m1(){ return true; }}3. abstract class Class2 implements Base {}4. abstract class Class2 implements Base { public boolean m1(){ return (7 > 4); }}5. abstract class Class2 implements Base { protected boolean m1(){ return (5 > 7) }}