THE MOLECULAR BASIS OF INHERITANCE
DNA REPLICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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5’ T T T A A A G 3’
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3’ T T T A A A G 5’
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5’ A A A T T T C 3’
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3’ U U U A A A G 5’
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Detailed explanation-1: -DNA is always synthesized in the 5’-to-3’ direction, meaning that nucleotides are added only to the 3’ end of the growing strand. As shown in Figure 2, the 5’-phosphate group of the new nucleotide binds to the 3’-OH group of the last nucleotide of the growing strand.
Detailed explanation-2: -The sequence of the mentioned DNA strand is 5’-ATCAGC-3’. So, the sequence of the complementary strand will be 3’-TAGTCG-5’.
Detailed explanation-3: -Which way’s which? When we look at a sequence of DNA, we read it in the 5′-3′ direction. The relative positions of genes or other sites along a DNA strand can be described as upstream (towards the 5′ end) or downstream (towards the 3′ end).
Detailed explanation-4: -If one strand of a DNA molecule has the sequence of bases 5’ATTGCA3’, the other complementary, antiparallel strand of DNA would have the sequence: 5’TGCAAT3’.