Question

Which of the following condition will occur, if the chromosomes of a eukaryotic cell lack telomerase?

• A. Have a greater potential to become cancerous than one with telomerase
• B. Would be able to repair mismatched base pairs during replication
• C. Not produce okazaki fragments
• D. Become increasingly shorter with each cycle of replication
• E. Be unable to take up extraneous DNA from the surrounding solution

Answer 1

The correct option is D Become increasingly shorter with each cycle of replication

DNA polymerase can not synthesize DNA de novo and needs primer causing problem in replication of ends of the chromosomes. Telomeres are the structures present at the ends of linear eukaryotic chromosomes and have mostly guanine residues in one strand and cytosine in the complementary strand. The G-rich strand is longer leaving a region of single-stranded DNA of up to a few hundred nucleotides at the 3’ end which serves as a primer for its elongation by telomerase enzyme. Telomerase contains both RNA and protein components. The RNA component is150 nucleotides long and has about 1.5 copies of the appropriate CyAx telomere repeat which serves as a template for synthesis of the TxGy strand of the telomere of linear DNA. In absence of telomerase enzyme, telomeres won't get replicated and chromosome will get shorter with each cycle of replication.
So, the correct answer is option D.