Question

The telomeres of eukaryotic chromosomes consist of short sequences of
A. Adenine rich repeats
B. Guanine rich repeats
C. Thymine rich repeats
D. Cytosine rich repeats

Answer 1

Hint: Telomeres are basically repetitive nucleotide sequences present at the terminal ends of linear chromosomes of almost all eukaryotic organisms. Most prokaryotes, generally lack this linear arrangement, and hence are devoid of telomeres; this is only found in the eukaryotic organisms.

Complete answer: The telomere DNA sequences are proper arrays of short guanine-rich repetitive sequences that ultimately terminates in a 3 single-strand G-rich overhang (approx. 150200 nucleotides), in most of the eukaryotic chromosomes.
The G-rich strand is essentially synthesized by a telomere-specific RT, which is also known as telomerase, using a small region of its RNA subunit as template and the 3-OH towards the end of the chromosome as a primer.
For vertebrates, the sequence of nucleotides in telomeres is almost identical. So, the telomeres of eukaryotic chromosomes consist of short sequences of guanine rich repeats and not cytosine, adenine and thymine repeats.
In human beings, the telomeres contain up to several thousand repeats of the specific sequence TTAGGG.

So, the correct answer is B. Guanine rich repeats.

Note: Without telomeres, the strands of DNA would become damaged and therefore telomeres are very essential for the proper functioning of the cell.
It is also believed that the length of the telomeres is directly linked to the process of aging.
Several genetic as well as microscopic observations have indicated that the telomere basically serves to stabilize the chromosomal ends from shortening through progressive loss of DNA.