Base analogs are a class of chemical mutagens that have a similar chemical struc

Question

Base analogs are a class of chemical mutagens that have a similar chemical structure to a normal nucleotide such that DNA polymerase cannot differentiate them. The base analog, 5'-bromouracil, competes with the normal base thymine during DNA replication and results in point mutations (i.e. base substitutions). Normal nucleotide base Analog Br O CHO Normally, 5-bromouracil can pair with adenine just like thymine, but it possible for it to mispair with guanine. H N H-N -bromouracil Adenine 5-bromouracil (enol form) Guanine (keto form) Normal pairing The following shows what can happen when 5-bromouracil pairs with guanine by mistake Normal DNA in place of thymine First replication cycle: bU pairs with guanine Second replication cycle: bU pairs with ???? Base-pair substitution in daughter DNA molecules Fill in the following blanks: (input A, T, C, or G), and the After the second replication event, the thymine (T on the top strand has changed to a(n) adenine (A) on the bottom strand has changed to a(n) (input A, T, C, or G) This is an example of a (input transition or transversion) type of base substitution.

Explanation / Answer

Answer ) after second replication thymine is replaced by the bromo uracil and adenine is replaced by guanosine.

This is known as transition mutations because single ring member replaced single ring that is purine to purine and pyrimidine to pyrimidine.

Answer a) when an error is done in newly synthesized DNA strand than it is known as incorporation error and when this error is replicated in further strand than it is known as replication error. Answer B)yes both errors can be corrected because initially mismatch repair occur than only base excision repair occur.

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