In which phase of cell division do the chromosomes replicate?

Question

In which phase of cell division do the chromosomes replicate??  
A. Prophase  
B. Interphase  
C. Anaphase  
D. Telophase

Accepted Answer

Correct Answer: (B)Interphase. 
Rationale: Chromosomes replicate during interphase.Before a cell can divide, it must first make an exact copy of its genetic material so that each daughter cell will receive a complete and identical set of chromosomes. This replication of DNA occurs during a specific part of interphase called the S phase (synthesis phase). Interphase is therefore the stage in the cell cycle when chromosome duplication takes place, preparing the cell for mitosis or meiosis.A) ProphaseProphase is the first stage of mitosis. During this phase, the already-replicated chromosomes condense and become visible under a microscope as paired sister chromatids joined at the centromere. The nuclear membrane begins to break down and the spindle apparatus starts to form. However, no DNA replication occurs in prophase. The copying of chromosomes has already been completed earlier during interphase, so this option is incorrect.B) InterphaseInterphase is the longest phase of the cell cycle and consists of three sub-phases:G1 phase, where the cell grows and carries out normal metabolic activitiesS phase, where DNA replication occursG2 phase, where the cell continues to grow and prepares for divisionDuring the S phase, each chromosome is duplicated to form two identical sister chromatids. This ensures genetic continuity so that both daughter cells receive the same genetic information after division. Without this step, proper cell division would not be possible.C) AnaphaseAnaphase is a stage of mitosis in which the sister chromatids separate and are pulled to opposite poles of the cell by spindle fibers. At this point, DNA replication has long been completed. The cell is distributing the copied chromosomes, not making new ones. Therefore, anaphase is not the correct phase.D) TelophaseTelophase is the final stage of mitosis. During this phase, chromosomes begin to decondense back into chromatin, nuclear membranes reform around each set of chromosomes, and the cell prepares to complete division through cytokinesis. DNA replication does not occur here, making this option incorrect.ConclusionChromosome replication is a crucial preparatory step that occurs before cell division begins. This process takes place during the S phase of interphase, ensuring that each new cell receives a full set of genetic instructions. Therefore, the correct answer is B) Interphase.

In which phase of cell division do the chromosomes replicate?

A
Prophase

B
Interphase

C
Anaphase

D
Telophase

Chromosomes replicate during interphase.

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Related Questions

In which phase of cell division do the chromosomes replicate?

A Prophase B Interphase C Anaphase D Telophase

Chromosomes replicate during interphase.

Topic Flashcards

Mini Quiz

Related Questions

A
Prophase

B
Interphase

C
Anaphase

D
Telophase