Question

a mutation is identified in a single-celled eukaryote called a protist in which dna primase does not assemble rna primers on the lagging strand during dna replication. which of the following statements correctly describes a possible result of this mutation?

dna replication will proceed normally.
the leading strand will not be replicated normally.
the lagging strand will continue to be replicated normally.
the lagging strand will not be replicated normally.

Explanation:

To solve this, we analyze DNA replication:

1. DNA primase synthesizes RNA primers. For the lagging strand (synthesized as Okazaki fragments), RNA primers are needed to start each fragment.
2. If DNA primase fails to make RNA primers on the lagging strand, DNA polymerase can't start synthesizing DNA there.
3. Analyzing options:

• "DNA replication will proceed normally" is wrong (lagging strand needs primers).
• "The leading strand will not be replicated normally" is wrong (leading strand has one primer, and the mutation is about lagging strand primers).
• "The lagging strand will continue to be replicated normally" is wrong (no primers mean no start for DNA synthesis on lagging strand).
• "The lagging strand will not be replicated normally" is correct (no RNA primers, so DNA replication on lagging strand is impaired).

Answer:

D. The lagging strand will not be replicated normally.