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Multiple Choice
Which of the following statements best describes the structure of DNA?
A
DNA is a triple helix with three strands intertwined.
B
DNA is a double helix composed of two strands running in opposite directions.
C
DNA is a single-stranded molecule with a linear sequence of nucleotides.
D
DNA is a circular molecule found only in prokaryotic cells.
Verified step by step guidance
1
Begin by understanding the basic structure of DNA. DNA, or deoxyribonucleic acid, is the molecule that carries genetic information in living organisms.
DNA is known for its double helix structure, which consists of two strands that are twisted around each other. This structure was first described by James Watson and Francis Crick in 1953.
Each strand of the DNA helix is composed of nucleotides, which are the building blocks of DNA. A nucleotide consists of a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base.
The two strands of DNA run in opposite directions, a feature known as antiparallel orientation. This means one strand runs in a 5' to 3' direction, while the other runs 3' to 5'.
DNA is not a triple helix, single-stranded, or exclusively circular. While circular DNA can be found in prokaryotes, the typical structure of DNA in most organisms is the double helix.