What does cytosine always pair with?

In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.

Does guanine pair with cytosine?

Guanine pairs with cytosine, and adenine pairs with thymine in DNA. Interstrand hydrogen bonds are responsible for this pairing.

What hold cytosine and guanine together?

hydrogen bonds
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.

How does guanine bind to cytosine?

Guanine has two tautomeric forms, the major keto form (see figures) and rare enol form. It binds to cytosine through three hydrogen bonds. In cytosine, the amino group acts as the hydrogen bond donor and the C-2 carbonyl and the N-3 amine as the hydrogen-bond acceptors.

What happens when cytosine and guanine join together?

When nucleotides join together, they can form the nucleic acids DNA and RNA. When cytosine is on one strand of a nucleic acid, the other strand will contain a guanine to match. These two are friends because they fit together perfectly with three hydrogen bonds. Cytosine can be easily converted into other bases,…

How are adenine, guanine, and thymine related?

Adenine and guanine have a fused-ring skeletal structure derived of purine, hence they are called purine bases. Similarly, the simple-ring structure of cytosine, uracil, and thymine is derived of pyrimidine, so those three bases are called the pyrimidine bases.

Who is the best instructor for cytosine biology?

Instructor: Beth Skwarecki. Cytosine is one of the bases that spell out genes in your DNA. It is so versatile that it’s been called the ‘wild card’ of nucleic acids. Learn about the structure and functions of the letter ‘C’ in DNA’s alphabet!

What makes a cytosine a pyrimidine or a purine?

Structure. As a nitrogenous base, cytosine is full of nitrogen atoms (it has three). It also has one ring of carbon, which makes it a pyrimidine. A purine, on the other hand, has two rings of carbon. There are two pyrimidines, cytosine and thymine, and two purines, adenine and guanine, in DNA.