What would happen if a purine paired with a purine?

Two complementary strands of the DNA can accommodate only three nitrogen rings between them. More or fewer nitrogen rings will not fit because of space issues. Thus, purine-purine cannot pair with each other due to the unavailability of the required space to bond together in the DNA double helix.

Can two purines be paired with one another?

Chargaff’s rule, also known as the complementary base pairing rule, states that DNA base pairs are always adenine with thymine (A-T) and cytosine with guanine (C-G). A purine always pairs with a pyrimidine and vice versa.

Can purine pair with purine?

The Watson-Crick G·C and A·T base-paired DNA duplex has been the single most important milestone in modern molecular biology. However, it is possible that other types of stable DNA structures besides the double helix might exist, since only about 5\% of the human chromosome is transcribed and expressed.

What would happen if two purines bonded?

Each base pair should consist of one pyrimidine and one purine, held together by hydrogen bonds. If paired correctly, each base pair will consist of three ‘rings’. If two purines paired there would be four ‘rings’ and they wouldn’t fit or would distort the structure of the DNA molecule.

Why is it important that a purine always pairs with a pyrimidine?

Purine always pairs with pyrimidines due to its structural properties. The structure of purines allows them to make hydrogen bonds with pyrimidines….

What is advantage of purine base pair with another purine?

Dictated by specific hydrogen bonding patterns ,base pairs between Guanine (G) – Cytosine (C) and Adenine (A) – Thymine (T) , allow the DNA helix to maintain a regular helical structure.

Are purines double ringed?

The purines (adenine and guanine) have a two-ringed structure consisting of a nine-membered molecule with four nitrogen atoms, as you can see in the two figures below. The pyrimidines (cytosine, uracil, and thymine) only have one single ring, which has just six members and two nitrogen atoms.

Why do pyrimidines pair with purines?

Explanation: Pairing of a specific purine to a pyrimidine is due to the structure and properties of these bases. Matching base pairs ( purines and pyrimidines ) form hydrogen bonds. A and T have two sites where they form hydrogen bonds to each other.

How important is purine and pyrimidine base pairing in DNA replication?

The purines on one strand of DNA form hydrogen bonds with the corresponding pyrimidines on the opposite strand of DNA, and vice versa, to hold the two strands together. Because hydrogen bonds are not as strong as covalent bonds, base pairings can easily be separated, allowing for replication and transcription.

Why do purines have to pair with a pyrimidine quizlet?

Notice that each base pair consists of a purine and a pyrimidine. The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds.

Why can’t two purines pair up with each other?

Therefore, during pairing in DNA, two purines cannot pair up together because there is not much space enough between the two DNA helical strands to accommodate two purine groups, and thereby FOUR RINGS. Hence while DNA pairing, a purine always pairs up with a pyrimidine. Click to see full answer

Do purines only bond with pyrimidines?

In the C-G pair, the purine (guanine) has three binding sites, and so does the pyrimidine (cytosine). The hydrogen bonding between complementary bases is what holds the two strands of DNA together. One may also ask, do purines only bond with pyrimidines?

What is the structure of purine?

Purine is a heterocyclic aromatic organic compound that consists of a pyrimidine ring fused to an imidazole ring, i.e., a purine will always have TWO RINGS in its structure. In DNA pairing the space between the strands can accommodate ONLY THREE RINGS, NOT MORE AND NOT LESS.

What happens if the purines in DNA strands bonded to each other?

If the purines in DNA strands bonded to each other instead of to the pyrimidines, they would be so wide that the pyrimidines would not be able to reach other pyrimidines or purines on the other side! The space between them would be so large that the DNA strand would not be able to be held together.