Mbk-4 Cell Lab Report

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.

Station one: Station one shows that when a small piece of magnesium metal is placed over the flame of the Bunsen burner, the magnesium metal ignites, giving off a bright, white light. Once the flame has extinguished itself due to the lack of fuel, the magnesium metal turned from a metallic strip to a crumbled white powder. It can be decided that station one is a combination (redox) reaction, as a new product is synthesised by the combination of two reactants. The reactants, magnesium and oxygen gas in the air bonded together to form the product of magnesium oxide.

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,

Since AMPK sites in ULK1 are conserved, the group also examined if the two proteins work together in autophagy conservation in C. elegans using reporter assay and histogram plots.

16) If the S phase were eliminated from the cell cycle, the daughter cells would

At the 12-cell stage of embryogenesis, new P1 decendants(MS and E) will become signalling cells. GLP-1/Notch still remains on the surfaces of the ABa descendants. According to genetic studies done by Shelton and Bowerman (2005), signals from MS and E are identified as products of embryonically-transcribed genes. Since MS will be in contact with 2 out of 4 ABa descendants GLP-1 will be activated. Thus, ref-1 will be expressed. On the other hand, for ABp descendants, they are refractive to second Notch interaction even though they contact MS or E but still continue the GLP-1/Notch

As in many other species, the mid-blastula transition (MBT) marks a crucial transition in the embryogenesis of Drosophila, including the dramatic lengthening of cell cycle and the onset of cellularization. Although the tenth nuclear cycle (nc) is claimed to be the initial point of zygotic gene expression in Drosophila (Edgar and Schubiger, 1986), the dependency on zygotic gene activity does not become obvious until nc 14, during which the Drosophila embryo undergoes the decrease of the first wave of zygotic transcription, as well as the progressive emergence of a massive second wave.

The Yeast two-hybrid system was used in this investigation to find which of four DNA inserts codes for a protein able to interact through protein-protein interactions with the protein encoded by the Bub1B gene. The protein encoded by the Bub1B gene is a kinase, which has a role in the formation of the mitotic spindle checkpoint ‘Davenporta et al. (1998)’

Using a compound microscope, it can be determined what type of cell(plant, animal, or bacterial) the mystery cell is. After first setting up the microscope correctly you can view the specimen at 40x power. At 40x power, key observations can be made to help place the cell in a group. If the cell contains a rigid shape and little movement, a hypothesis can be made that the cell is a plant cell as the rigid shape would be caused by a cell wall, only found within plant cells. In that case, you would stain the cell using iodine as it would react with the starch and show other organelles within the cell in addition to bringing the microscope power to 400x power (skipping 100x as it is unnecessary). At 400x power, it may be possible to observe a chloroplast

The MAPK signalling pathway also undergoes an additional step of JunB synthesis that ultimately leads to Runx2 phosphorylation and formation of the Smad-Runx2 complex, a critical step where any disruption would mean a loss of Runx2 transcriptional activation23,24. Hereafter, both the canonical and non-canonical Smad pathways converge to regulate Runx2 gene transcription, and thereby regulate MSC differentiation into

D. melanogaster is also an excellent model organism in studying embryological development due to its aforementioned similarities with the human genome. Certain homeobox genes found in the D. melanogaster

Discuss in detail the effects that an activating mutation in the IKBKB gene would be expected to have on the downstream signalling pathway components and target gene expression, and how these effects are measured in the article.

In worms, DTC functions as GSC niche (Kimble and White, 1981). In hermaphrodites, distal end of each gonad has one DTC while in males; both DTCs are located at the end of a single gonad. DTC sends cytoplasmic processes which envelop the neighboring cells and hence, provide them a niche. DTC signals nearby cells to remain mitotically proliferating and as cells move away from it; they are no longer under the influence of these signals and hence, enter meiosis. DTC is crucial for larval germ cell proliferation and for the maintenance of GSCs in adults. Laser ablation of DTC results in the loss of mitotically dividing due to precocious meiotic entry. Conversely, ectopic localization of DTC relocates stem cell population and its duplication forms a new pool of mitotically proliferating stem cells. Therefore, DTC is necessary as well as sufficient for the mitotic proliferation of GSCs (Byrd and Kimble, 2009; Kimble and White, 1981). Approximately 230 mitotically proliferating cells are present at the distal end of the gonad, which spreads to ~ 20 cell diameters from the DTC (Crittenden et al., 1994; Hansen et al., 2004a). Label retaining assays using BrdU and EdU; and other studies of cell cycle kinetics have revealed that there are two subpopulations within the 230 mitotically dividing cells. Distal most ~130-160 cells are actively proliferating while ~ 70-90 cells present more proximal to distal end within the mitotic zone are in premeiotic S-phase (Crittendenet al., 2006 ;

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.

The organization of microtubules (MTs) in the mitotic spindle apparatus has been shown to involve a combination of centrosomal-based nucleation and hypothesized to involve acentrosomal branching MT nucleation. Here, Petry et al. (2013) uses Xenopus egg extracts to successfully observe branching MT nucleation from existing microtubules utilizing total internal reflection microscopy (TIRF). Direct observation of branching MT nucleation highlighted both the activating effect of RanQ69L and its effector protein TPX2 on branching MT nucleation, and the polarity conservation of daughter MTs. Testing for required molecular factors using immunodepletion, it was shown that the γ-tubulin ring complex (γ-TuRC) is required for primary nucleation while the protein complex augmin is required for branching. Furthermore, components of the RanGTP signaling pathway are shown to induce observed branching MT nucleation.