10 (g) Page 56-60 Cell Cycle: Interphase, Mitosis (PMAT) and Cytokinesis
The regular sequence of growth and division that cells undergo is known as the cell cycle. During the cell cycle, a cell grows, prepares for division, and divides into two new cells, which are called “daughter cells.” Each of the daughter cells then begins the cell cycle again. Notice that the cell cycle is divided into three main stages: interphase, mitosis, and cytokinesis.
1. interphase, 2. mitosis, and 3. cytokinesis.
1. interphase, 2. mitosis, and 3. cytokinesis.
Stage 1: Interphase
The first stage of the cell cycle is called interphase. Interphase is the period before cell division. During interphase, the cell grows, makes a copy of its DNA, and prepares to divide into two cells.
Stage 2: Mitosis (pmat)
Once interphase is complete, the second stage of the cell cycle begins. Mitosis (my toh sis) is the stage during which the cell’s nucleus divides into two new nuclei. During mitosis, one copy of the DNA is distributed into each of the two daughter cells.
Scientists divide mitosis into four parts, or phases: prophase, metaphase, anaphase, and telophase.
prophase, metaphase, anaphase, and telophase.
During prophase, the threadlike chromatin in the nucleus condenses to form double-rod structures called chromosomes. Each chromosome has two rods because the cell’s DNA has replicated, and each rod in a chromosome is an exact copy of the other. Each identical rod in a chromosome is called a chromatid. Notice in Figure 11 that the two chromatids are held together by a structure called a centromere.
As the cell progresses through metaphase, anaphase, and telophase, the chromatids separate from each other and move to opposite ends of the cell. Then two nuclei form around the chromatids at the two ends of the cell.
The first stage of the cell cycle is called interphase. Interphase is the period before cell division. During interphase, the cell grows, makes a copy of its DNA, and prepares to divide into two cells.
Stage 2: Mitosis (pmat)
Once interphase is complete, the second stage of the cell cycle begins. Mitosis (my toh sis) is the stage during which the cell’s nucleus divides into two new nuclei. During mitosis, one copy of the DNA is distributed into each of the two daughter cells.
Scientists divide mitosis into four parts, or phases: prophase, metaphase, anaphase, and telophase.
prophase, metaphase, anaphase, and telophase.
During prophase, the threadlike chromatin in the nucleus condenses to form double-rod structures called chromosomes. Each chromosome has two rods because the cell’s DNA has replicated, and each rod in a chromosome is an exact copy of the other. Each identical rod in a chromosome is called a chromatid. Notice in Figure 11 that the two chromatids are held together by a structure called a centromere.
As the cell progresses through metaphase, anaphase, and telophase, the chromatids separate from each other and move to opposite ends of the cell. Then two nuclei form around the chromatids at the two ends of the cell.
Stage 3: Cytokinesis
The final stage of the cell cycle, which is called cytokinesis (sy toh kih nee sis), completes the process of cell division. During cytokinesis, the cytoplasm divides. The organelles are distributed into each of the two new cells. Cytokinesis usually starts at about the same time as telophase. When cytokinesis is complete, two new cells, or daughter cells, have formed. Each daughter cell has the same number of chromosomes as the original parent cell. At the end of cytokinesis, each cell enters interphase, and the cycle begins again.
The final stage of the cell cycle, which is called cytokinesis (sy toh kih nee sis), completes the process of cell division. During cytokinesis, the cytoplasm divides. The organelles are distributed into each of the two new cells. Cytokinesis usually starts at about the same time as telophase. When cytokinesis is complete, two new cells, or daughter cells, have formed. Each daughter cell has the same number of chromosomes as the original parent cell. At the end of cytokinesis, each cell enters interphase, and the cycle begins again.
