The following are correct statements
(A) DNA produces double stranded breakage and can be reaired to produce inversion chromosomes
(B) Chromosome rearrangement can produce acentric chromosome
(D) acentric chromosomes can replicate and separate normally
(E) acentric chromosomes will produce anaphase bridges during anaphase. Two correct answers for each question.
The correct answer and explanation is:
The correct answers are:
- (A) DNA produces double-stranded breakage and can be repaired to produce inversion chromosomes.
- (E) Acentric chromosomes will produce anaphase bridges during anaphase.
Explanation:
- (A) DNA produces double-stranded breakage and can be repaired to produce inversion chromosomes:
Double-strand breaks in DNA are a type of damage that can occur during processes like replication, radiation exposure, or other forms of genetic stress. These breaks are dangerous because if not properly repaired, they can lead to chromosomal instability. However, the repair mechanism known as homologous recombination or non-homologous end joining can sometimes lead to rearrangements such as inversions. Inversions occur when a segment of a chromosome is reversed end to end. This can affect gene expression and chromosome structure, potentially leading to various genetic disorders or diseases. The rejoining of broken chromosome ends in a way that flips a DNA segment is a common repair error that leads to inversion. - (E) Acentric chromosomes will produce anaphase bridges during anaphase:
Acentric chromosomes are chromosomes that lack a centromere, which is essential for proper segregation during cell division. Without a centromere, these chromosomes cannot attach to the mitotic spindle during anaphase, the stage of cell division where chromosomes are separated into daughter cells. As a result, acentric chromosomes cannot be properly pulled apart and instead get tangled or form bridges. These bridges can stretch between the two daughter cells, causing instability during the separation process and potentially leading to cell death or improper chromosomal distribution. The presence of anaphase bridges is a hallmark of the abnormal behavior of acentric chromosomes during cell division.
Incorrect answers:
- (B) Chromosome rearrangement can produce acentric chromosomes:
While chromosome rearrangements such as deletions, duplications, inversions, and translocations can occur, acentric chromosomes are generally the result of the loss of the centromere, not the rearrangement itself. Rearrangements can cause structural changes in chromosomes, but the formation of acentric chromosomes requires a loss or absence of the centromere. - (D) Acentric chromosomes can replicate and separate normally:
Acentric chromosomes lack a centromere, which is necessary for the proper attachment to the spindle during cell division. Without the centromere, the chromosomes cannot replicate and separate normally, as they will not be correctly distributed between daughter cells during anaphase.