Question

Antiparallel strands of a DNA molecule means that
(A) One strand turns anti- clockwise
(B) The phosphate groups of two DNA strands at their ends, share the same position.
(C) The phosphate groups at the start of two DNA strands are in the opposite position (pole).
(D) One strand turns clockwise.

Answer 1

Hint: The DNA is the deoxy ribonucleic acid. It is the genetic material that pass from the parent to the offspring. It contains the morphological and the genetic characters of the organisms. DNA is the double helix structure that is present in the chromosomes of the cells.

Complete answer:
The antiparallel strands of DNA molecules indicate that the phosphate groups at the beginning of the two DNA strands are in opposite positions. DNA is composed of two polynucleotide chains (polymers of nucleotides), forming a ladder. The two polynucleotide chains extend "anti-parallel" to each other, with nitrogen-containing bases protruding inward. The term "antiparallel" means that the strands extend in opposite directions parallel to each other.
The antiparallel strands are twisted in a complete DNA structure to form a double helix. The strands twist to each other forming the double helix DNA structure. It consists of the $3' - 5'$ and the \[5' - 3'\] linkage. The \[5' - 3'\] indicates the five prime and the three prime and it indicates the number of carbons in the DNA backbone. The five prime consists of the phosphate group and the three prime consists of the hydroxyl group. This alternate five and the three prime gives the asymmetry DNA strands.

Hence the correct answer is OPTION(C)

Note: The DNA structure is made of the phosphate, nitrogenous bases and the sugar. In DNA the nitrogenous bases are adenine, guanine, thymine and the cytosine. Here the adenine and the guanine are the purine and the thymine and the cytosine are the pyrimidine.