Question

which of the following would prevent dna replication from starting?
loss of single - stranded binding proteins
non - functional telomerase
overactive topoisomerase
missing rna primer

Explanation:

• Single - stranded binding proteins: These proteins bind to the unwound DNA strands to prevent them from re - annealing. Their loss would affect the stability of the single - stranded DNA during replication but not necessarily prevent replication from starting.
• Telomerase: Telomerase is involved in maintaining the length of telomeres (the ends of chromosomes). Non - functional telomerase would lead to telomere shortening over time but does not prevent the initiation of DNA replication.
• Topoisomerase: Topoisomerase relieves the supercoiling of DNA. Overactive topoisomerase may cause issues with DNA structure during replication but is not the factor that prevents replication from starting.
• RNA primer: DNA polymerase (the enzyme that synthesizes new DNA strands) requires a free 3' - OH group to add nucleotides. The RNA primer provides this free 3' - OH group. Without an RNA primer, DNA polymerase cannot start synthesizing the new DNA strand, thus preventing DNA replication from starting.

Answer:

missing RNA primer