Question

Number the following steps in the correct order and tell which stage it occurs in:

Answer 1

Answer:

d. Genetic material replicates and is joined at the centromere ----- INTERPHASE

b. Chromosomes line up at the equator and chromatids are attached to spindle fibers---- METAPHASE

e. Centromeres divide and single-stranded chromosomes move to the poles ---- ANAPHASE

c. Nuclear membrane and nucleolus reappear ---- TELOPHASE

a. A cleavage furrow or cell plate forms, separating the nuclei ---- CYTOKINESIS

Explanation:

This question depicts the events that occur in the cell cycle. The cell cycle begins with the preparatory phase called INTERPHASE and stops at the cytoplasm division called CYTOKINESIS. The correct order of the options in this question are:

1. D - The genetic material (DNA) replicates at the Interphase stage, specifically the Synthesis phase. The DNA replication is one of the steps the cell takes during the Interphase to prepare itself for division. The replication of DNA forms a structure called SISTER CHROMATIDS, which are replicated chromosomes held at the Centromere.

2. B - After the Interphase stage, comes the actual division (Mitosis). This option shows what occurs in the Metaphase stage of Mitosis. The spindle microtubules attaches to the kinetochore of each chromosome (sister chromatids) and they become aligned at the equator/middle of the cell.

3. E -- This option shows the occurrences in the Anaphase stage of Mitosis. The aligned chromosomes are separated and pulled apart towards opposite poles of the cell by the spindle fibres. Each pole contains a single strand chromatid of a pair. This is actually the essence of the replication process in Interphase stage.

4. C -- After the division of the nuclear material (chromosomes), a process called KARYOKINESIS, the important structures begin to reform in each pole of the cell during the Telophase stage. Prior to separation of chromosomes at the Anaphase stage, the membrane that bounds the nucleus called NUCLEAR MEMBRANE alongside the nucleolus is degraded in order for the spindle microtubules to assess the chromosomes. These structures form at each pole during Telophase stage.

5. A -- After karyokinesis (division of nuclear material), the cytoplasmic content of the cell needs to separate into two in a process called Cytokinesis. Cytokinesis occurs differently in plant and animal cells. Plant cells forms a cell plate due to their cell wall while Animal cells form a cleavage furrow at the equator of the cell.