The Pros And Cons Of The Eukaryotic Cell Cycle

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

You would expect for the normal lung cells to not have to divide as often because those cells are not exposed to many things through out the day. The normal stomach cells on the other hand would be expected to divide more because there is a lot of acidity in the stomach and therefore those cells are exposed to a lot of things on a daily basis. As for the ovaries you would expect that there would be a little more cell division because that is where new life is formed and all of the things that come along with that which means that there should be more division going on.

In the context of the cell cycle, P53 is shown to have a G1 and G2/M checkpoint function [23]; in fact, upon receiving a stimulus such as DNA damage, p53 induces cell cycle arrest providing time for the cell to repair the genomic damage before being released back into the proliferating pool . The best known P53 target gene product involved in this process is the cyclin-dependent kinase (CDK) inhibitor p21 [18]. The progression through the S phase of the cell cycle is tightly controlled by CDKs [19]. P21 functions by inhibiting Cyclin-CDK complexes, therefore, hindering the cell cycle transition from G1 to S phase [23]. In addition to being implicated in the G1/S arrest of the cell cycle, it has been demonstrated that P21, alongside p53, is also essential in the G2/M phase [23,

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.

They have identified key molecules that regulate the cell cycle in all eukaryotic organisms, including yeasts, plants, animals and human. These fundamental discoveries have a great impact on all aspects of cell growth. Defects in cell cycle control may lead to the type of chromosome alterations seen in cancer cells. This may in the long-term open

possible error allowing repair thus achieving high fidelity in transcription. Also, the DNA damage response system can activate checkpoints inducing cell cycle arrest, allowing time for different mechanisms such as Base, Nucleotide Excision Repair and Mismatch Repair system which, involving specialized proteins, will excise and repair the incurred error.

PC3 (8×104  cells/well) and LNCaP (3×105  cells/well) cells were seeded in 6-well plates in 1.5  mL of complete growth media. Cells were treated with 2.5 μM of free sorafenib or an equivalent sorafenib concentration of SMA-Sor, 3 μM of free nilotinib or an equivalent nilotinib concentration of SMA-Nilo, DMSO or SMA for 48  h. Cell cycle distribution was assessed using propidium iodide staining, as previously described {Somers-Edgar, 2011 #82}. Samples were analysed using a FACScalibur flow cytometer (BD Biosciences, San Jose, CA, USA) and the proportion of cells in each of G0/G1-, S- and G2/M-phases were determined using CellQuest Pro software (BD Biosciences, San Jose, CA, USA).

On September 12, 1016, Belmont University graciously allowed Dr. Katherine Friedman from Vanderbilt University to come and talk to a crowd of students about the tendencies of how deoxyribose double stranded breaks can during cell replication and the elements required to hopefully repair this ordeal. She began the session by discussing what chromosomes are composed of and how they are produced, accompanied by visual and statistical representations. Moving on, she touched on how double strand breaks are a huge threat to a cell's, an organisms, stability. Correspondingly, she described what can cause these breaks; chemical factors, as well as inner cell disruptions during replication that are sometimes hard to remedy. However, she also stated that this breaks can occur on purpose, mostly in the immune system in efforts to make antibodies.

The normal process of cell division is altered in cancerous cells typically by mutations in the genes involved in the regulation of cellular division. The number of mutations normally will begin to spread because when the genes that make DNA repairing proteins become mutated, this causes the DNA that they would be repairing to become mutated as well. Some changes allow the damaged cells to divide more quickly than normal and to invade other tissues. The cancers cells can divide even where there are signals and normal cells meant to prevent the cell growth.

There are multiple cell cycle regulation mechanisms that organisms use. Please discuss density-dependent inhibition and anchorage dependence.

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

(#2) CDKN1A is a protein coding gene. The purpose CDKN1A serves in the cell is that it works as cell cycle regulator at the G1 checkpoint and is responsible for the cell cycle arrest at that checkpoint. CDKN1A encodes a potential cyclin-dependent kinase (CDK) inhibitor which then prevents the phosphorylation of critical CDK substrates and blocks cell cycle progression, thus functioning as a cell cycle regulator at the G1 checkpoint. CDKN1A, along with p53, are both involved

The research that was conducted had the specific purpose of addressing questions on topics of individuality, reproduction, symbiotic relationships, all based around the idea of endosymbionts and the endosymbiotic theory with the eukaryotic cell. Symbiosis are the relationships between organisms that can either harm or benefit themselves. And the topic of symbiosis brings questions to the table about evolution, individuality, and cooperation between the organisms, especially when the eukaryotic cell and the evolution of it is involved; however, before we delve into these questions it is important to operationally define reproduction. In this case reproduction has evolved over time into three forms of itself: simple, collective, and scaffolded. Simple can be easily defined in the form of prokaryotes and bacteria. Collective can be described as humans, as we have reproducing parts inside of ourselves(cells). And scaffolded can be explained as reproductive objects that reproduce based entirely on surrounding resources, with the example being viruses. We will discuss how reproduction and the evolution of it applies to the eukaryotic cell as well. The conceptual framework that will be discussed in further detail later on, was made to further discuss Lewontin’s view on evolution by natural selection. He proposed three

Next up is the Krebs cycle, which simply picks up where glycolysis left off. The Krebs cycle, or otherwise referred to as, the Citric Acid cycle, or the TCA Cycle, is extremely pertinent in cellular respiration. In fact, without this process, respiration could not be possible. Reason being, is the Krebs cycle takes the pyruvate molecules that were present in glycolysis in order to create high energy molecules necessary for the electron transport chain (ETC) which follows soon after. One of the interesting things about cell respiration is that it is part of an essentially universal "toolkit" that characterizes all of life, at least for life involving eukaryotic

cycle? A. B. C. D. G1 mitosis G1 G1     S G1 G2 G2    G2 G2 S  mitosis  cytokinesis S