Which enzyme is responsible for proofreading?
What happens if a nitrogen base is paired wrong?
When there is a mistake in the copying of the genetic message that is permanent, a mutation has occurred. Two of the bases in DNA (Cytosine and Thymine) are the most vulnerable, and when this happens, they may pair with each other or themselves and the message is changed.
How are base pairs formed?
Each base pair is formed from two complementary nucleotides (purine with pyrimidine) bound together by hydrogen bonds. The base pairs in DNA are adenine with thymine and cytosine with guanine. DNA has a spiral staircase-like structure.
Why does a only pair with T?
as seen in the figure, two hydrogen bonds are formed between Adenine and Thymine , three hydrogen bonds are formed between cytosine and guanine. This is because the Adenine( purine base ) pairs only with the Thymine(pyrimidine base ) and not with Cytosine(purine base). The base pairing obeys Erwin Chargaff’s rules.
How many base pairs does a gene have?
Genes vary in size, from just a few thousand pairs of nucleotides (or “base pairs”) to over two million base pairs.