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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1’
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2’
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3’
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4’
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5’
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Detailed explanation-1: -As new nucleotides are added to a strand of DNA or RNA, the strand grows at its 3’ end, with the 5′ phosphate of an incoming nucleotide attaching to the hydroxyl group at the 3’ end of the chain.
Detailed explanation-2: -A nucleotide has a tri-phosphate group attached to the sugar moiety. When it is added to a growing DNA strand, two phosphates (a pyrophosphate) are released and this provides the energy to link the new nucleotide to the DNA strand via the remaining phosphate group. This bond is called phosphodiester bond.
Detailed explanation-3: -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-4: -One of the key molecules in DNA replication is the enzyme DNA polymerase. DNA polymerases are responsible for synthesizing DNA: they add nucleotides one by one to the growing DNA chain, incorporating only those that are complementary to the template.
Detailed explanation-5: -DNA polymerase adds nucleotides to the 3’ end of a primer, extending the new chain in a 5’