Table of Contents
- 1 How do the double helix structure and the base pairing rules help to produce two new DNA molecules that are identical to the original DNA molecule?
- 2 How does base pairing in the double helix explain how DNA can be replicated?
- 3 What causes DNA to replicate?
- 4 What actually happens to DNA before it can be replicated copied?
- 5 How do we know DNA is a double helix?
- 6 What are the features of the DNA double helix?
How do the double helix structure and the base pairing rules help to produce two new DNA molecules that are identical to the original DNA molecule?
Because the two strands of a DNA molecule have complementary base pairs, the nucleotide sequence of each strand automatically supplies the information needed to produce its partner. Each template and its new complement together then form a new DNA double helix, identical to the original.
How does base pairing in the double helix explain how DNA can be replicated?
The double-helical structure immediately suggests how DNA is replicated. 1. The two strands of the double helix have a tremendous affinity for one another, created by the cooperative effects of the many hydrogen bonds that hold adjacent base pairs together. The DNA helix must be unwound to separate the two strands.
How are the nucleotide base pairs of the DNA double helix linked together?
Genetic information is carried in the linear sequence of nucleotides in DNA. Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs.
How is the double helix structure related to the function of DNA?
DNA winds into a double helix, with hydrogen bonding between the bases of each strand like the rungs of a ladder. This structure enables DNA to coil so that the long molecule is compact and lots of information can be stored in a small space.
What causes DNA to replicate?
What triggers replication? Figure 1: Helicase (yellow) unwinds the double helix. The initiation of DNA replication occurs in two steps. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.
What actually happens to DNA before it can be replicated copied?
Before replication can occur, the length of the DNA double helix about to be copied must be unwound. In addition, the two strands must be separated, much like the two sides of a zipper, by breaking the weak hydrogen bonds that link the paired bases.
What are the two strands in a DNA double helix joined by?
The two strands are held together by bonds between the bases, adenine forming a base pair with thymine, and cytosine forming a base pair with guanine.
Why does the DNA double helix have a uniform?
The diameter of the DNA double helix is uniform throughout because a purine (two rings) always pairs with a pyrimidine (one ring) and their combined lengths are always equal.
How do we know DNA is a double helix?
KEY FACTX-ray diffraction of DNA crystals results in a cross shape on the X-ray film, which is typical of a molecule with a helix shape. James and Francis used evidence shared by others, particularly Rosalind Franklin and Maurice Wilkins, to determine the shape of DNA.
What are the features of the DNA double helix?
Double Helix A DNA molecule consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating groups of sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases: adenine (A), cytosine (C), guanine (G), or thymine (T).
What happens if DNA does not replicate?
If cells don’t replicate their DNA or don’t do it completely, the daughter cell will end up with no DNA or only part of the DNA. This cell will likely die. Cells also copy their DNA right before a special cell division event called meiosis, which results in special cells called gametes (also known as eggs and sperm.)
Which cell stage does DNA replicate?
In the eukaryotic cell cycle, chromosome duplication occurs during “S phase” (the phase of DNA synthesis) and chromosome segregation occurs during “M phase” (the mitosis phase).