Actively Daviding Experiment

Preparing specimen for electron microscope hard, light microscope still very useful as a window on living cells.

Add three seeds to the potting mix and cover seeds with little remaining potting mix. After the addition of the potting mix, use a dropper filled with water and water each cell until water drips from the wick. Then place the quads on a watering tray under the fluorescent light bank. Each cell should have an equal distance from the light bank. Quads should be three inches below the fluorescent light; the light should also be left on all day. Make sure all wicks are in contact with the mat that sits on the watering tray. Also watch out for the watering system regularly throughout the experiment. After four to five days record plants in the quads, giving their phenotypes in a table for each cell removed all but the strongest plant.

In the onion root tip, regions other than the apical (or at top of) meristem contain cells that are not actively dividing. These cells are in interphase. In this case, they would represent the majority because cells spend most of their time in interphase anyway. They are elongating, differentiating, and performing their functions for the organism. Mitotic stages would not have been found in these areas.

After a week, the phenotypes of the plants were recorded in Table 2. The strongest plant in each cell was left in the quad, and the others were removed in order to thin the plants.

In this experiment first the stages of an onion cell undergoing mitosis are going to be observed and every stage is going to be detected and drawn on paper. A brief description to what is going on should be attached to the pictures. This is important to understand the basics of cell division which is necessary growth,repair and asexual reproduction. Second the number of cells undergoing each phase is going to be counted to figure out in which phase the cell remains the most. If interphase is the stage in which the cell grows and prepares for cell division then the

Normally, the roots grow a little downward with many roots branching from the main bulb.

The Principles and Limitations of Transmission and Scanning Electron Microscopes Introduction Microscopy has a major role in cytology. From the very beginning researchers have tried to develop ways of looking directly at living cells. This examination has revealed much about the morphology of cells and tissues. In recent years,development in microscopes,dyes,staining and preparatory techniques have helped reveal even more about the structure and function of cells.

As seen from the given figure, the paper discovered that a single promoter (pFLS2) differentially drove gene expression in response to different stimuli using transcription fusion of pFLS2 with GUS. Specifically, they discovered that in the control treatment, pFLS2 was solely visible in root late elongation. While incubation with flg22 led to an increase Pfls2 activity in the root tip extending to the cortical cells, salylic acid (SA) showed strong blue staining in the vasculature, next H2O2 or the ethylene precursor ACC provoked an almost identical promoter activity in the root cap, root meristem and root epidermal cells, also finding pFLS2 is auxin responsive. Revealing that flg22, SA, H2O2 and ethylene all induce the expression of activity of the pFLS2 but the responses are specific to different tissue layers in the root. Overall proving evidence that a single promoter can drive expression to different tissues because of cis-regulatory elements, presenting observations showing that FLS2 is subject to positive regulation between receptor

- Fixation stabilizes the cell and tissue structure. It also denatures proteolytic enzymes, and it helps keep the cell from contamination and disintegration. Fixation also help the sample be able to go through staining and other techniques further down the road.

The aim of this technique is to embed tissue into wax. Embedding tissue into paraffin blocks supports the tissue structure and enables to cut very thin sections and mount them onto microscope slides for posterior staining and analysis. I prepared tissue on paraffin sections for staining. This technique is divided in different steps, most of them made automatically by a machine:

The flower dissection will allow students to learn the flower reproductive parts and their functions. By actually seeing a real life model, students should be engaged and remember this lab on future tests. Students will be able to view flower parts under a microscope so they can grasp the picture of the real life model of a plant’s ovules. This is an engaging lab for students because they get to use lab instruments to dissect and gain practice using a microscope. Learning goal 5 is practiced throughout the lab activity.

Mitosis is a vital process for all cells where one single cell divides into two identical daughter cells. This procedure encompasses four distinct phases called prophase, metaphase, anaphase, and telophase in order to ensure cell regeneration and growth. A stage called interphase where the cell grows and undergoes DNA replication is a vital part to cell division, which precedes mitosis. The onion root lab aims to view two distinct parts of the specimen’s tip, area x and y, under a light microscope to determine at which location cell division happens at a more frequent rate. If area Y, the middle right section of the onion root, is observed, then there will be a smaller concentration of cells undergoing cell division. If the area X, the bottom left section of the onion root, is observed, then there will be a greater concentration of cells undergoing cell division.

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.

To observe mitosis in onion root tip cells and record the different phases of mitosis.

having two distinct zones are seen. The upper zone consists of 5-7 layers of thin