Question

Which of the following statements about DNA is not correct?
A.It has a double helix structure.
B.It undergoes replication.
C.The two strands in DNA molecule are exactly non complementary
D.It contains the pentose sugar-2-deoxyribose.

Answer 1

Hint: To approach this question, we should know the difference between DNA and RNA. DNA is a deoxyribose nucleic acid and RNA is ribonucleic acid. They help us in carrying the genetic codes. The former is self- replicating in nature and the latter does not have such property.

Complete step by step solution: There are four types of macromolecules that are required for every living organism. These four macromolecules are proteins, lipids and nucleic acids and carbohydrates. So talking about the DNA we say that they are the part of the nucleic acids. Further talking about the nucleic acid, there are two types of nucleic acids DNA and RNA. 
Full form of RNA is ribonucleic acid and the full form of DNA is deoxyribonucleic acid. Then further talking about the DNA, it is a double stranded structure which is known to carry the genetic material. It is considered as a double stranded structure which is said to be composed of a polynucleotide chain which further coil around each other to form a double strand. Further talking about it we can say that the genetic material which it carries gives further instructions for growth and development. Also as it is the monomeric units of nucleotides that means it undergoes replication in order to become a double stranded structure. Then as we know that it has undergone replication in order to become double stranded therefore we can conclude that they are complementary to each other. For sure as it is a type of nucleic acid therefore it is made up of pentose sugar -2- deoxyribose. So we can conclude from this that the third statement is incorrect about the nucleic acid which says that the two strands are not complementary to each other.

Hence, option C is the correct answer to the above asked question.

Note: Genomics is the study of DNA of an organism and associated technology. It is an interesting fact to note that in many viruses, RNA replaces DNA as a carrier of genetic codes. G-C and A-T base pairs are observed in DNA and thus they form two complementary strands of nucleotides.