Problem 4 - Biology

Question

At which stage of meiosis are sister chromatids separated from each other? a. prophase I b. prophase II c. anaphase I d. anaphase II

Step-by-Step Solution

Answer

The correct answer is d. anaphase II.

Step 1: Identify Key Terms

Recognize the important terms in the question: 'meiosis,' 'sister chromatids,' and 'separated.'

Step 2: Understand the Stages of Meiosis

Meiosis consists of two main stages: meiosis I and meiosis II. Each stage has sub-stages: prophase, metaphase, anaphase, and telophase.

Step 3: Functions of Meiosis I

In meiosis I, homologous chromosomes (each consisting of sister chromatids) are separated from each other. However, sister chromatids remain together. This separation occurs during anaphase I.

Step 4: Functions of Meiosis II

In meiosis II, sister chromatids are finally separated. This process is similar to mitosis and occurs during anaphase II.

Step 5: Match Stages to Options

Given the options: a. prophase I b. prophase II c. anaphase I d. anaphase IIWe recognize that sister chromatids are separated during anaphase II.

Step 6: Conclusion

The correct stage of meiosis where sister chromatids are separated is anaphase II.

Key Concepts

sister chromatids separation

Understanding the separation of sister chromatids is essential in grasping the process of meiosis. Sister chromatids are identical copies of a single chromosome that are connected by a centromere. During cell division, it's crucial for these chromatids to be separated and move to different daughter cells. This identical separation ensures that each new cell contains the exact genetic information.
In the context of meiosis, this separation occurs in meiosis II. Up until this stage, the sister chromatids stay together. Specifically, when cells reach anaphase II, the spindle fibers pull the sister chromatids apart to opposite poles of the cell. This assures each new cell receives one copy of each chromosome, preserving genetic consistency.

anaphase II

Anaphase II is one of the crucial stages in meiosis II. It comes right after metaphase II, where chromosomes line up at the metaphase plate. During anaphase II, the centromeres that hold the sister chromatids together are finally split. This allows the chromatids to be pulled apart by the spindle fibers.
The separated chromatids, now individual chromosomes, move towards opposite poles of the cell. Each pole will eventually form the nucleus of a new cell. This proper separation is critical to ensure that each resulting gamete receives the right number of chromosomes. Incorrect separation can result in genetic disorders, highlighting the importance of this stage.

meiosis II

Meiosis II is the second division phase in meiosis, following meiosis I. Unlike meiosis I, which separates homologous chromosomes, meiosis II deals with the separation of sister chromatids.
Here are the stages of meiosis II:

• Prophase II: Chromosomes condense and become visible, the nuclear envelope breaks down, and spindle fibers form.
• Metaphase II: Chromosomes line up along the central metaphase plate.
• Anaphase II: Sister chromatids are separated and pulled to opposite poles of the cell.
• Telophase II: Chromatids arrive at the poles, nuclear membranes form around each set, and the cell divides, usually through cytokinesis.

Meiosis II results in four haploid cells, each with a unique combination of chromosomes. These cells are crucial for sexual reproduction, contributing to genetic diversity in offspring.