Question

Look at the bottom and top of the "ladder" in Model 1. Are the rungs parallel (the ends of the strands match) or antiparallel (the ends of the strands are opposites)?

1) Parallel
2) Antiparallel

Answer 1

The rungs of the DNA ladder are antiparallel, which indicates the strands run in opposite directions. This antiparallel configuration is fundamental to the structure and function of DNA.

Step-by-step explanation:

The rungs of the DNA ladder in Model 1 are antiparallel. This means that the two strands of DNA run in opposite directions, with one strand running from the 5' to 3' direction and the other running from the 3' to 5' direction. Both strands of DNA have a backbone composed of alternating deoxyribose (sugar) and phosphate groups, which form the sides of the ladder, while the rungs are made up of nitrogenous bases bonded together through hydrogen bonds.

In DNA, adenine pairs with thymine, and cytosine pairs with guanine, creating the steps that make up the double helix structure. The two strands' alignment is crucial for DNA's functions, including replication and genetic information encoding.

The rungs of the ladder in DNA are antiparallel, meaning that the two strands run in opposite directions. One strand runs from a 5' to 3' direction, while the other strand runs from a 3' to 5' direction. This antiparallel arrangement allows for the complementary base pairing between the strands, where adenine always bonds with thymine and guanine always bonds with cytosine.