Question

which is false about end of chromosome replication?
since dna replication occurs in 5→3 direction, an rna primer exists on lagging strand
telomerase adds rna bases to 3 end of parent strand
telomerase is a reverse transcriptase
even with telomerase activity, ends of chromosomes still shorten over time
dna polymerase iii will synthesize the remaining section of the daughter strand

Explanation:

1. DNA replication occurs in 5'→3' direction and an RNA primer is needed on the lagging - strand, so the first statement is true.
2. Telomerase is a reverse - transcriptase enzyme that adds DNA bases (not RNA bases) to the 3' end of the parent strand, so the second statement is false.
3. Telomerase is indeed a reverse transcriptase, which uses an RNA template to synthesize DNA, so the third statement is true.
4. Even with telomerase activity, the ends of chromosomes can still shorten over time due to factors like incomplete replication, so the fourth statement is true.
5. DNA polymerase III synthesizes the DNA strand during replication, including the remaining section of the daughter strand, so the fifth statement is true.

Answer:

B. Telomerase adds RNA bases to 3' end of parent strand