Question

Which of the following is not true about chromosome structure?

• A. A telomere is always on the end of a eukaryotic chromosome.
• B. A centromere is always in the middle of a eukaryotic chromosome.
• C. The kinetochore is the site of attachment of the centromeres to the nuclear spindle apparatus.
• D. Heterochromatin is primarily associated with the centromere and telomere regions.

Answer 1

Answer: (B)

A centromere is always in the middle of a eukaryotic chromosome.

• A centromere is the specialized structure DNA sequence of a chromosome that links a pair of sister chromatids. During cell division, spindle fibers attach to centromere through kinetochore.
  
• Centromere position may be defined in three ways: metacentric, submetacentric or acrocentric.
  
• Metacentric is the most common position of the centromere found. In this, the centromere lies near the center of the chromosome.
  
• Submetacentric chromosomes have a centromere a little off-center, such that one chromosome is much longer than the other.
  
• In acrocentric chromosomes, centromere lies very close to the one end of the chromosome.
  

So, the correct option is 'A centromere is always in the middle of a eukaryotic chromosome'.