Aim:
To observe mitosis in onion root tip cells and record the different phases of mitosis.
Hypothesis:
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.
Background Information:
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.
Interphase is often called the resting stage of mitosis. It is a stage in the life cycle of a cell where, putting it simply, DNA is replicated and each
Exercise 3A is a study of mitosis. You will simulate the stages of mitosis by using chromosome models.You will use prepared slides of onion root tips to study plant mitosis and to calculate the relative duration of the phases of mitosis in the meristem of root tissue. Prepared slides of the whitefish blastula will be used to study mitosis in animal cells and to compare animal mitosis and plant mitosis.
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
According to the data table, prophase is the longest stage of mitosis. Even though there were more tallies in the interphase section, interphase is not considered a stage of the mitotic cycle; it is more or less considered a stage in the cell cycle. Telophase is the shortest stage because there were very few cells that showed evidence of them actually being in this stage. Metaphase and anaphase are intermediate stages, with metaphase being longer than anaphase.
These bivalents line up along the equator during metaphase I, the arrangement of the bivalent is completely random and relative to the orientation of the other bivalents, this is known as the independent assortment of chromosomes. This is followed by anaphase I where the homologous chromosomes separate and move to the opposite poles of the cell. At telophase I the cell divides into two, each cell contains one chromosome from each homologous pair. The second stage of meiosis is similar to mitosis.
Mitosis and meiosis are similar in several ways and different in others. The similarities include that both processes involve IPMAT. IPMAT is interphase, prophase, metaphase, anaphase and telophase. The parent cells are diploid. They both end with cytokinesis. In Metaphase and Metaphase II, the sister chromatids line up along the center. Then in Anaphase and Anaphase II, these chromatids are split and pulled towards the centrosomes. The differences are that mitosis consists of 1 division while meiosis consists of 2. Four genetically different, haploid sex cells are the products of meiosis and 2 identical, diploid somatic cells from mitosis. Mitosis occurs in all organisms except viruses and meiosis only occurs in plants, animals, and fungi.
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).
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.
19) The phase of mitosis during which the nuclear envelope fragments and the nucleoli disappear is called
cell will look just like any other 'normal' cell although this is far from the
Plants are organisms that can reproduce sexually through meiosis and create more cells through mitosis (Russell et al. 2013). For studying mitosis, the common onion is an ideal choice. Because it is easy for onions to germinate without soil, it is easy to control any substances provided to the plant. The onion root tips are only a few cells thick and grow quickly making them ideal for time efficiency. The onion root tip needs to be squashed between the cover slip and the microscope in order to reduce the slide preparation’s total depth. To dye condensed chromosomes, such as those undergoing mitosis, a stain is used to make
Yes, we could locate the various stages of mitosis. The prophase, metaphase, anaphase, and telophase stages were clearly present in the cells.
Resting phase: More appropriately called interphase. The interval in the cell cycle between two cell divisions when the individual chromosomes cannot be distinguished, interphase was once thought to be the resting phase but it is far from a time of rest for the cell. It is the time when DNA is replicated in the cell nucleus.
Interphase is the phase GF in which it’s the cell’s cycle is in a typical cell and it spends most of it’s life in. During this phase the cell copies its DNA,in it’s preparation for mitosis.The interphase is the daily living, of the metabolic phase of the cell, in it’s the cell obtains the nutrients and metabolizes them,and they grows, and reads its DNA, and the conducts from other "normal" cell functions.
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,