Question

Separation of the sister chromatids is a characteristic of which stage of mitosis? a. prometaphase b. metaphase c. anaphase d. telophase

Short answer

Answer: (c) anaphase

Step-by-step solution

Identify the stages of mitosis

Mitosis is divided into four main stages: prophase, metaphase, anaphase, and telophase.

Review the characteristics of each stage

In prophase, the chromosomes condense, the nuclear envelope breaks down, and the spindle apparatus forms. During metaphase, chromosomes align at the equatorial plane of the cell. Anaphase is characterized by the separation of sister chromatids, which move towards opposite poles of the cell. Lastly, telophase is the stage during which the nuclear envelope forms around each set of chromosomes and the cell begins to divide.

Select the correct stage for sister chromatid separation

Based on the characteristics of each stage, it is evident that the separation of sister chromatids occurs during anaphase.

Match the answer with the given options

In the given options, a. prometaphase b. metaphase c. anaphase d. telophase The correct answer is (c) anaphase.

Key concepts

Sister Chromatids

Sister chromatids are identical copies of a single chromosome that are connected by a structure called a centromere. Chromosomes are duplicated during a phase called interphase, leading to the formation of sister chromatids. Essentially, they are like mirrored halves of the same chromosome. This duplication is crucial for genetic consistency.

During the early stages of mitosis, such as prophase, these chromatids become tightly coiled, making them easier to align and eventually separate. Their primary role is to ensure that each new cell receives an identical set of chromosomes once cell division is complete.

It's important to note the distinction between sister chromatids and homologous chromosomes. The former are exact duplicates, whereas homologous chromosomes are similar but not identical pairs you get from each parent.

Anaphase

Anaphase is the stage of mitosis where the dramatic separation of sister chromatids occurs. During this stage, the paired chromatids, which were lined up during metaphase, are pulled apart by the spindle fibers attached to the centromeres. This movement guides each chromatid to opposite poles of the cell.

This separation is a critical step in ensuring that each daughter cell will receive an identical set of genetic material, mirroring what was present in the original parent cell. The force that drives this separation is produced by the shortening of microtubules, components of the spindle fibers.

Without proper chromatid separation during anaphase, cells could receive an inordinate number of chromosomes, leading to conditions like aneuploidy, which can cause several disorders or diseases.

Cell Division Stages

Cell division occurs in a highly ordered sequence of stages that culminates in the production of two identical daughter cells. Mitosis is the process utilized by eukaryotic cells to ensure equal chromosome distribution.

The sequence begins with prophase, where chromatin condenses, forming recognizable chromosomes. The nuclear envelope dissolves, and the spindle apparatus takes shape. Metaphase follows, characterized by chromosomes aligning at the cell center. It ensures that each sister chromatid is distorted and properly aligned for even separation.

• Prophase: Chromosomes condense, spindle forms.
• Metaphase: Chromosomes line up at the equator.
• Anaphase: Sister chromatids separate.
• Telophase: Nuclear envelopes reform, and the cell begins to split.

The mitotic sequence concludes with telophase, where new nuclear membranes form around the separated chromatids now termed chromosomes again, and the cell prepares for the final physical division, or cytokinesis. Understanding these stages helps explain how cellular life functions accurately and efficiently.