Stages Of The Cell Cycle Essay

Interphase: This particular stage is divided into three phases, G1 (first gap), S (synthesis), and G2 (second gap). During all three phases, the cell grows by producing proteins and other organelles within the cytoplasm. However, chromosomes are replicated only during the S phase. In all, a cell grows (G1), continues to grow as it duplicates its

These centrioles replicate and the chromosomes line along the equator at metaphase II and spilt at the centromeres causing the chromatids to move to opposite sides at anaphase II. At telophase II the cell divides to form four haploid cells, these are not identical to each other because the cells contains chromosomes from two different parent gametes therefore differ genetically. However, during mitotic division the cells produced are genetically identical to each other because they are produced from the same parent cell. The cell begins to replicate during interphase to produce two identical sister chromatids.

In M phase (Mitosis), the DNA and proteins in each chromosome form highly compacted structures

2. In which phases of mitosis are sister chromatids visible, and attached to each other at the centromere?

Although mitosis is just a fraction of time compared to interphase it can be divided into four distinct subphases. If we start viewing a cell under a brightfield microscope right at the end of interphase subphase G2 we would see that throughout the interphase process (fig 1) the cell has grown considerably in size due to production of extra mitochondria and endoplasmic reticulum. The cell has also gone through the labor of duplicating all of its chromosomes, a process known as DNA synthesis. Now that the cell has made all of these preparations it's time to start prophase (fig 2), the first stage of the mitotic phase. This stage is visibly identified by the chromatin becoming the tightly formed chromosomes. During the lab we were able to view these newly formed chromosomes best on the onion root tip

The cell cycle is a series of stages that occurs when a new cells makes the division from the parent cell to two daughter cells. This is a stage in cellular reproduction. The cell cycle consists of three phases, interphase, mitosis, and cytokinesis. During Interphase, a cell will continue to perform its functions as usual. The time frame for Interphase varies; while an embryonic cell will take just a few hours to complete the cycle, a stem cell from an adult can take 24 hours (Mader, Windelspecht, 2015). After the interphase stage completes itself, a complete nuclear division happens and mitosis occurs. During the stage of mitosis, the daughter cells will receive the same amounts of the contents of the parent cell. Throughout the last stage, in the cytoplasm there is a division known as Cytokinesis (Mader, Windelspecht, 2015). Cytokinesis occurs differently in plant cells than it does in animal cells, as the cell wall around the plant prevents the process from happening the same way. Instead, a new plasma membrane and cell walls are built are built between the daughter cells. However, in animal cells a single cell will become two (Mader, Windelspecht, 2015).

The phase in mitosis which chromatin begins to coil and the mitotic spindle begins to form.

Page 20: Sam says, “I’m learning so much, could you tell me the next phase”. Yes, replied the fairy, the next is anaphase during this process the spindles grab the center of the chromosomes called the centromere which binds the two chromatids to form a chromosome. The spindles pull at the chromosomes to the opposite

19) The phase of mitosis during which the nuclear envelope fragments and the nucleoli disappear is called

The cell cycle has four main stages. The cell cycle is the regular pattern of growth. The four stages consist of Gap 1 (G1), Synthesis (S), Gap 2 (G2), and Mitosis (M). Gap 1, consists of a cell that carries its normal functions. Calls also increase in size, and the organelles increase in number. A cell will spend the most time in this phase. But it also depends on the cell type to see how long it will spend in this phase. During this phase the cell has to pass a critical checkpoint before it can continue into the (S) stage, also called the Synthesis stage. It would be dangerous for a cell to keep dividing if the certain conditions were not met. The cells in this stage also need signals from the other cells to tell the if division is needed. Now the next stage is the Synthesis stage. During this phase the cell makes a copy of it’s nuclear DNA. By the end of the (S) phase DNA appears grainy in photos and the cell nucleus contains two complete sets of DNA. Gap 2, is the third stage of the cell cycle. The cells continue doing there thing and more growth occurs. This phase is like the checkpoint, everything in the cell has to be going right for the cell to be able to enter mitosis.

[A labelled diagram of the end of the Prophase stage of a cell here would be

Interphase is often called the resting stage of mitosis. It is a stage in the life cycle of a cell where, putting it simply, DNA is replicated and each

There are four stages of mitosis. The first stage is the prophase. In this stage the chromosomes become

The lag phase is when the organisms are first place into a new medium and will take time to get used the their new environment. During this phase, organisms will grow in size but cannot replicate. The next phase is the log phase. In this phase cells are dividing and growing at a very fast rate. DNA replication begins in this phase as well as their metabolic rate starts to increase rapidly. (Bacterial Growth Curve) Cells divide by binary fission. The organisms will eventually reach maximum growth and start to level off beginning the next phase, the stationary phase. In this phase, the bacterial population will start to slow down and stop dividing because the nutrients needed for them to grow are being used up. The pH and temperatures start to shift making the environment and unfavorable one and the accumulation of waste and toxic metabolites the growth starts to die off, transitioning into the last and final stage. (Bacterial Growth Curve) The death phase is when there is longer any nutrients to grow and to much waste has built up along with toxic materials, killing the cells. However, some organisms can withstand this environment and begin to produce endospores. (Bacterial Growth Curve)

The main focus of this lab was to be able to understand the different phases of mitosis and the cell cycle and also identify what those stages may look like. Mitosis is the process in which concerns the production of new cells. For example, when apoptosis(cell death) the process of Mitosis begins to replace the dead cells. To be able to familiarize ourselves with this concept, we took a sample of an onion root and had it put through a process to be able to look at the different phases under the microscope. We found that the majority of the cells were mostly undergoing Interphase or Prophase which are the phases in charge of crossing over of DNA and where the chromosomes then become visible and the nuclear envelope dissipates. The conclusion of this lab was that Mitosis is essential for the production of new cells. In the case of the onion root sample, the cells were damaged leading to the tester to undergo Mitotic cell division and it was found that mainly Interphase and Prophase were the stages that occurred in this lab.