Problem 66 - Objective Biology for NEET

Question

The separation of daughter chromosomes occurs in (a) The beginning of anaphase (b) Metaphase (c) Late prophase (d) Early prophase

Step-by-Step Solution

Answer

The separation of daughter chromosomes occurs in (a) The beginning of anaphase

Step 1: Identify the stages of mitosis

The mitosis phase of a eukaryotic cell cycle is subdivided into prophase, metaphase, anaphase, and telophase.

Step 2: Understand what happens in anaphase

In anaphase, the sister chromatids separate and move towards opposite poles. This process is often referred to as the daughter chromosomes being pulled apart.

Step 3: Compare with other options

Prophase, metaphase, and telophase do not involve the separation of daughter chromosomes. Thus, these stages can be ruled out.

Key Concepts

Anaphase

In the dynamic process of mitosis, anaphase plays a crucial role in cell division. It is a stage where duplicated chromosomes, known as sister chromatids, are separated and pulled towards opposite poles of the cell. This movement is facilitated by the spindle apparatus, which is made up of microtubules. The centromeres, the central part of the chromosome, divide, allowing the sister chromatids to part ways.

Once separated, these chromatids are referred to as daughter chromosomes. This transition from chromatids to daughter chromosomes is essential for ensuring that each daughter cell receives an identical set of chromosomes. Consequently, anaphase ensures genetic consistency and integrity across newly formed cells. It is the hallmark moment when cell potential is realized, allowing for growth, development, and repair.

Recognizing the critical transition of chromatid to chromosome during anaphase is fundamental in understanding both cell reproduction and genetic stability in organisms.

Chromosome Separation

Chromosome separation is a key event in the mitotic process of eukaryotic cells. It is vital for distributing the cell's genetic material equally between the two newly formed daughter cells. This process begins during anaphase when each chromatid, previously bound together at the centromere, is pulled apart by spindle fibers.

The spindle fibers attach themselves to the centromere of each chromatid using kinetochores—protein complexes that regulate attachment and movement. As the spindle fibers shorten, they effectively drag the chromatids away from each other, directing them towards opposite poles of the cell. This movement is powered by motor proteins that traverse along the spindle fibers.

Successful chromosome separation ensures that each daughter cell acquires a complete set of chromosomes, preserving genetic information across cellular generations. Missteps in this process can lead to genetic disorders or diseases, emphasizing the importance of precise regulation and execution in cellular division.

Eukaryotic Cell Cycle

The eukaryotic cell cycle is an orchestrated series of phases through which a cell passes to duplicate and divide. The cycle is divided into two main parts: interphase and the mitotic (M) phase. Interphase consists of G1, S (synthesis), and G2 phases, where the cell grows, DNA replicates, and the cell prepares for division, respectively.

During the mitotic phase, the cell undergoes a visible transformation as it divides its contents and nucleus to form two daughter cells. Mitosis is further broken down into specific stages: prophase, metaphase, anaphase, and telophase. Each phase plays a distinct role, with anaphase being particularly important for chromosome separation.

Understanding the eukaryotic cell cycle is critical to understanding how living organisms grow and maintain their genetic integrity over time. The interplay of regulatory signals and checkpoints within this cycle ensures cells divide correctly and at the right time, preventing uncontrolled cell division that could lead to tumorigenesis.