Chromatin condenses into chromosomes, spindle fibers form, and the nuclear membrane begins to break down. So the answer that correctly describes prophase is option (A). This completes mitosis: a single parent cell is divided into two identical daughter cells. This results in the formation of two daughter nuclei, and the original cell begins to split into two. This describes what happens in telophase, which is the fourth and final stage of mitosis. So answer (C) is incorrect.įinally, answer choice (D) says that two nuclear membranes begin to reform around the chromosomes. And anaphase is the stage where the chromosomes are being pulled apart. You can remember what happens in anaphase because it starts with the letter A, just like the word apart. This describes what happens in the third phase of mitosis, anaphase. So answer choice (B) is incorrect.Īnswer choice (C) states that the spindle fibers shrink, pulling the chromosomes to opposite sides of the cell. You can remember what occurs in metaphase because it starts with the letter M, and so does the word middle, which is where the chromosomes line up in the cell. Chromatin strands condense & coil, appearing as linear structures attached. This describes metaphase, which is the second stage of mitosis, which you can see here. Answer choice (B) says pairs of chromosomes line up along the equator, or the middle, of the cell and spindle fibers attach to each chromosome. Let’s look through the rest of the options before we come to a conclusion. A cell entering M phase manifests a number of physicsl signs. It follows G2, the final phase of interphase. The first phase of mitosis within M phase is called prophase. Since we are looking for the option that best describes prophase, this could be our answer. Entry into M phase is allowed by the formation of the mitotic cyclin-Cdk complex known as M phase-promoting factor that occurs as a cell cycle regulatory mechanism in the G2 phase. If we look at our answer choices, we can see that option (A) lists out all these events. The nuclear membrane also begins to break down during prophase. Spindle fibers are also formed in this stage, which will be used later. In prophase, the first step of mitosis, the chromatin in the nucleus of the cell begins to condense, so the chromosomes become visible. Let’s review the events that happen in each of these stages so we can answer our question. These four steps occur in the following order: prophase, metaphase, anaphase, and telophase. You might already know that mitosis is a process of cellular division and it has four distinct steps. In prophase I, the first stage is known as leptotene. Or (D) two nuclear membranes begin to reform around the chromosomes. Prophase II encompasses four different mechanisms namely the tight wrapping of DNA into chromosomes, the dissolving of the nuclear membrane, migration of the centrosomes (when present), and the reconstruction of the spindle apparatus. (C) Spindle fibers shrink and pull each chromosome to opposite sides of the cell. During the four phases of mitosis, nuclear division occurs in order for one cell to split into two. Additionally, we’ll mention three other intermediary stages (interphase, prometaphase, and cytokinesis) that play a role in mitosis. (B) Pairs of chromosomes line up along the equator, middle, of the cell, and spindle fibers attach to each chromosome. The four stages of mitosis are known as prophase, metaphase, anaphase, telophase. The major event marking a cells entry to prometaphase is the breakdown of the nuclear envelope into small vesicles. A new cell wall must form between the daughter cells.Which of the following correctly describes the events that occur in prophase? (A) Chromatin condenses into chromosomes, spindle fibers form, and the nuclear membrane begins to break down. There are 4 distinct phases of meiosis known as prophase, metaphase, anaphase, and telophase. In plant cells, a cleavage furrow is not possible because of the rigid cell walls surrounding the plasma membrane. Two cell divisions occur during meiosis, and the events of the first meiotic division.
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