Molecular genetics — antiparallel 3′/5′ strands and condensation reactions
“Option B was selected by a significant proportion… These candidates had not considered the role of condensation reactions in DNA replication or the 3′ and 5′ polarity of DNA strands.”
Add nucleotides to a growing strand. Each join is a condensation reaction (water released) onto the 3′ end, running antiparallel to the template.
Two exam points made visible: covalent backbone bonds form by condensation (water out), and the new strand is antiparallel, extended only at the 3′ end.
Original reconstruction inspired by the misconceptions described in the Singapore-Cambridge GCE A-Level H1 Biology 8876 November 2023 Examiner Report. Not the actual examination question. For classroom exploration.
Made by lookang, using Claude Fable 5. More resources: iwant2study.org