Question

Chromosome ends are called
A. Satellite
B. Telomeres
C. Centromeres
D. Kinetochore

Answer 1

Hint: Chromosomes are carriers of genes. A mitotic chromosome is formed of two identical strands known as chromatids. It has two arms separated by a thin segment called primary constriction.

Complete answer:
Chromosomes are formed of DNA and proteins. They are not visible in the cell nucleus even under a microscope when the cell is not dividing. During cell division, the DNA found tightly coiled many times around a protein called histones. Before the initiation of cell division, they undergo further condensation and form chromatids. The chromatids undergo replication and form copies of each chromatid, and they remain attached with the help of centromere. Each chromosome has a constriction point known as centromere which divides the chromosome into two parts or arms- a q arm and a p arm. The terminal end of the arm is known as telomeres. Telomeres are significant in that they form the termini of chromosomes, protect chromosomes from nuclease activity, and maintain the stability of chromosomes.
- Telomeres are the stable and non- sticky ends of a chromosome, which cannot attach or fuse with other chromosomes
- Telomeres are usually heterochromatic and are characteristic of having a simple repetitive DNA sequence.
- The centromere is a clear, constricted area within the primary constriction of the chromosome.
- It contains consecutive heterochromatin with highly repetitive DNA sequences, a bundle of microtubules, a thin disc or granules known as kinetochore
- The region flanking the centromere is densely packed with heterochromatin that contains highly repetitive DNA sequences known as satellite DNAs.
So, the answer is ‘B. Telomeres.

Note:: Telomeric end has the same DNA sequence in all chromosomes of a species. This telomeric sequence is maintained by the activity of the enzyme telomerase. The same telomeric sequence may be found in totally unrelated species. Telomeres prevent the end to end fusion of chromosomes.