Observing Mitotic Cell Cycle in the roots of Onion INTRODUCTION The cell cycle refers to sequence

     The leptotene. This phase differs only slightly from the early stages of mitosis. Usually are the cells and nuclei of meiotic tissues bigger than that of their neighbouring tissues and often do they seem to be longer and are longitudinally structured. At regular intervals can thickenings be found, like beads on a string: the chromomeres. Their number, size and positioning is constant in each species.

2) Why are onion root tip and whitefish blastula areas that are ideal to view mitosis?

Mitosis: This is the process by which a cell duplicates the chromosomes in its cell nucleus in order to generate two identical daughter nuclei.

“All types of cells undergo mitosis during formation of the embryo, but many adult cells, such as nerve cells, lens cells of the eye, and muscle cells, lost their ability to replicate and divide. The cells of other tissues, particularly epithelial cells [e.g., of the intestine, lung, skin), divide continuously and rapidly, competing the entire cell cycle in less than 10 hours” (McChance & Huether, pg. 35).

Without cell division and the cell cycle nearly all life would fail to exist. Cell division allows an organism to not only replace its own cells but to create offspring. The cell cycle consists of two main parts: interphase and mitotic phase. Within these two phases the processes can be broken down into further categories. Interphase can be broken down into three subphases that are the necessary preparations the cell makes in order to be ready to divide during mitosis. For this lab we looked mainly at the mitotic phase because of its fascinating and rapid changes to the cell. The cell types we looked at were prepared slides of whitefish and 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).

Find a representative cell for each stage of mitosis on the onion slide and draw a clear diagram of the different phases you observed in the accompanying space. Be sure to draw only what you see, but include all details that are visible. Your drawings will not necessarily look exactly like the ones in Figure 3A, 3B, 3C.

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

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

Mitosis is one of two main methods of cell replication, the other being meiosis. It is “the simple duplication of a cell and all of its parts” resulting from the splitting of a cell. The ‘parent’ or original cell splits, duplicating its DNA (packaged in chromosomes) producing two ‘daughter’ or new cells with the same genetic code. There are four stages of mitosis; Prophase, Metaphase, Anaphase and Telophase. Interphase is not an official phase of mitosis as the cell is at ‘rest’ and not being divided during this phase. It is often called one of the phases of mitosis as it is one of the stages in the life cycle of a cell; however it is not a phase of mitosis due to the fact that no division takes place.

What is a cell cycle? The activities that occur within a cell cycle from the end of one cell division to the end of another.

Sample response: Graph A represents a cell undergoing meiosis and Graph B represents a cell undergoing mitosis. In both mitosis and meiosis, the cell starts out with a certain mass of DNA that then doubles as DNA replication takes place during interphase. In mitosis, the cell undergoes the next set of stages including prophase, metaphase, and telophase without changing the quantity of DNA in the cell. When mitosis reaches telophase, the cell divides in two and so one-half of the DNA goes into one daughter cell and the other half goes into the other daughter cell. This results in two daughter cells with the same quantity of DNA as was present in the parent cell. In meiosis I, this same pattern of DNA mass change takes place as DNA replicates

According to the color of cell.Phases is prophase. On prophase everything are mixture together and there is no division.The image it shows color of black on the cell.whitefish blastula showing spindles.But also i can see the shape of the cell it almost like the circle one by one compose together with arrange.On the observation if watching carefully able to see some cell nucleus.And the happened is cytomembrane surround with the cell nucleus.

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.

© When studying cell division in tissue samples, scientists often calculate a mitotic index, which is the ratio of dividing cells to the total number of cells in the sample. Scientists often calculate the mitotic index to