Table of Contents
What connects the two strands of the DNA double helix?
The chemical backbones of the double helix are made up of sugar and phosphate molecules that are connected by chemical bonds, known as sugar-phosphate backbones. The two helical strands are connected through interactions between pairs of nucleotides, also called base pairs.
What connects the backbone strands in the middle?
The sugar and phosphate molecules form the outside strands of the helix, and the bases pair together in the middle, forming hydrogen bonds that hold the two sides of the helix together.
What connects the backbone of DNA?
The backbone of DNA consists of a phosphate group and a deoxyribose. These two components are therefore connected by a phosphodiester bond.
What joins the 2 DNA strands together?
The two strands are held together by hydrogen bonds between the bases, with adenine forming a base pair with thymine, and cytosine forming a base pair with guanine.
Why does DNA have a double helix shape?
The double comes from the fact that the helix is made of two long strands of DNA that are intertwined—sort of like a twisted ladder. Each strand of DNA (or side of the ladder) is a long, linear molecule made up of a backbone of sugars and phosphate groups. Connected to each sugar is a nitrogenous base.
What are the 5 nitrogenous bases?
Five nucleobases—adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U)—are called primary or canonical. They function as the fundamental units of the genetic code, with the bases A, G, C, and T being found in DNA while A, G, C, and U are found in RNA.
Why are DNA strands antiparallel?
The nitrogen bases can only pair in a certain way: A pairing with T and C pairing with G. Due to the base pairing, the DNA strands are complementary to each other, run in opposite directions, and are called antiparallel strands.
Which sugar is found in DNA?
deoxyribose
The sugar in deoxyribonucleic acid (DNA) is deoxyribose. The deoxy prefix indicates that the 2′ carbon atom of the sugar lacks the oxygen atom that is linked to the 2′ carbon atom of ribose (the sugar in ribonucleic acid, or RNA), as shown in Figure 5.2.
Which nitrogenous bases are in DNA?
All about DNA
- nitrogenous bases—there are four of these: adenine (A), thymine (T), cytosine (C), guanine (G)
- carbon sugar molecules.
- phosphate molecules.
Are the 2 strands of DNA identical?
The replication process Hydrogen bonds break and helix opens. Each strand of DNA acts as a template for synthesis of a new, complementary strand. Replication produces two identical DNA double helices, each with one new and one old strand.
What does 5 and 3 mean in DNA?
Each end of DNA molecule has a number. One end is referred to as 5′ (five prime) and the other end is referred to as 3′ (three prime). The 5′ and 3′ designations refer to the number of carbon atom in a deoxyribose sugar molecule to which a phosphate group bonds.