Which answer choice below correctly describes the structure of DNA?(1 point)
Responses
Sugar-phosphate backbone with nitrogen bases coming off a single helix.
Sugar-phosphate backbone with nitrogen bases coming off a single helix.
A sugar-phosphate backbone with nitrogen bases in the middle forming a double helix.
A sugar-phosphate backbone with nitrogen bases in the middle forming a double helix.
Sugar-nitrogen base backbone with phosphates in the middle forming a double helix.
Sugar-nitrogen base backbone with phosphates in the middle forming a double helix.
Nitrogen bases on the outside with sugar-phosphate in the middle of a double helix.
The correct answer choice is:
A sugar-phosphate backbone with nitrogen bases in the middle forming a double helix.
The correct answer choice is:
A sugar-phosphate backbone with nitrogen bases in the middle forming a double helix.
The correct answer choice that describes the structure of DNA is:
A sugar-phosphate backbone with nitrogen bases in the middle forming a double helix.
To understand why this answer is correct, let's break it down:
1. DNA is made up of two strands that are composed of repeating subunits called nucleotides. Each nucleotide consists of three components: a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base.
2. The sugar-phosphate backbone refers to the alternating sugar (deoxyribose) and phosphate groups that make up the sides of the DNA molecule. These sugar-phosphate backbones run in opposite directions, with the sugar of one strand facing the phosphate of the other strand.
3. The nitrogen bases are attached to the sugar molecules in the nucleotides and project inward toward the center of the DNA molecule. There are four types of nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). The bases on each strand are paired in a specific way: A always pairs with T, and C always pairs with G.
4. The arrangement of the two strands is known as a double helix because they twist around each other. The nitrogen bases form the "rungs" of the ladder, while the sugar-phosphate backbones form the "sides" or "rails" of the ladder.
Therefore, the correct structure of DNA is a sugar-phosphate backbone with nitrogen bases in the middle forming a double helix.