Cell Life Cycle Controlled By Genes Essay

In a cell cycle, there are specific checkpoints between each phases caused by the occurrence of cyclin. Cyclin determines how concentration flunctuatues. If the regulation is disrupted by a decreasein cyclin, there would be no mitosis, meaning the cell cycle would continuously go thre G0 phase. However, if there is an increase

Purpose: The purpose of this lab was to calculate the amount of time that was spent by a cell in each of the phases of mitosis. Also, it is used to be able to compare the process of mitosis between plant and animal cells.

“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).

after it isfully developed. Some cells divide to heal wounds such as cuts or broken bones.

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.

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

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

It is expected that the most common phase of mitosis seen will be interphase as the cell spends around ninety percent of its time in this phase. This is because interphase is the period between cell division in which the cells grows, DNA replicates and centrioles divide. It is such a long phase that it is even split into three sub-phases; G1 phase in which a cell grows, S phase or synthesis, in which a cell copies its chromosome and G2 phase in which the cell grows further and prepares for division.

In the G1 phase, cell synthesizes proteins and produces cytoplasmic organelles. In the S phase, DNA synthesis occurs, and in the G2 phase, the cell beings forming the spindle.

This is a list of the event occurring in the cell cycle from the list provided, ordered from first to last:

The first checkpoint is G1, this checkpoint is passed if there are enough nutrients, the size of the cell must be adequate, the DNA must be undamaged, and the signals from others cells must be present. If the cells pass this checkpoint then they will move on to the next checkpoint known as G2, but if it does not pass checkpoint G1 then the cells enter G0. In the second checkpoint G2 the cells must have undamaged DNA and the chromosomes are supposed to be well replicated. If the cells pass this checkpoint then it will go to the last checkpoint, here all of the chromosomes are attached to the mitotic

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 cell cycle is separated into multiple stages such as G0, G1, S, G2, and M phase. During the G0 phase is the stage in which there is no sign of the cell preparing to separate but, rather a stagnant cell. The G1 phase involves the expansion of the cell and gathering all the nutrients and energy to prepare for the upcoming processes of the cell cycle. In the S phase,