In the DNA molecule, what forms the steps or rungs of the double helix?
A
nitrogenous bases
B
sugar phosphate backbone
C
covalent bonds
D
hydrogen bonds
D
hydrogen bonds
In the DNA molecule, the steps or rungs of the double helix are formed by nitrogenous bases. Therefore, the correct answer is option A: nitrogenous bases.
The correct answer is D) hydrogen bonds. Hydrogen bonds form the steps or rungs of the double helix in the DNA molecule.
To arrive at this answer, we need to understand the structure of DNA. DNA is a double-stranded molecule that consists of two long strands twisted together to form a helical shape. The two strands are joined by hydrogen bonds between pairs of nitrogenous bases.
The DNA molecule is made up of four different nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair up in a specific way: adenine always pairs with thymine, and cytosine always pairs with guanine. This pairing is stabilized by hydrogen bonds.
The hydrogen bonds form between the nitrogenous bases on the two DNA strands. Specifically, hydrogen bonds are formed between adenine and thymine, as well as between cytosine and guanine. These hydrogen bonds hold the two DNA strands together and form the steps or rungs of the double helix structure.
So, in summary, hydrogen bonds form the steps or rungs of the double helix in the DNA molecule.