Meiosis in Motion

 

Meiosis is a specialized type of cell division where gametes (sex cells, sperm and/or eggs) divide twice results in the production of four haploid daughter cells. The resulting daughter cells have exactly half of the chromosomes as the starting cell. The stages of meiosis can be split into meiosis I and meiosis II, to identify the first and seconds splits. The first stage of meiosis I, interphase I is when the cell is doing its specified job and is replicating DNA. During second stage of meiosis, prophase I, chromatin is tightly coiled into chromosomes, then cross over to exchange information, the spindle fibers also begin to extend during this phase. In metaphase I, the homologue pairs line up along the metaphase plate and prepare for separation. The spindle fibers extend and pull apart the homologue pairs during anaphase I and move to opposite sides of the cell. Finally, in telophase I the chromosomes are at opposite sides of the cell and the cell membrane is split during cytokinesis (occurs at the end of telophase.) The processes of prophase, metaphase, anaphase, and telophase occur once again in meiosis II. The end result of the two splits are four haploid daughter cells.

The process of meiosis can be very confusing, especially with every important little piece that is involved. Taylor and I created a stop motion animation to breakdown and recreate the steps of meiosis. Although the entire process of creating the stop motion video was very time consuming, creating the animation overall helped us both understand the concept and steps of meiosis more thoroughly!

To check out the animation:

A Glimpse into a Possible Future

In class, we explored a game called “Face of the Future: A game about the Future of Empathy.” The game offers a scenario that occurs 10 years from now, allowing people from all over the world to interact and share their opinions and ideas on the scenario. People can post cards under “positive imagination” or “shadow information” where they display their perspective of the possible future, or can respond to the cards posted by others. I found the feature of being able to interact with people globally, very exciting because it was interesting to see the similarities and differences from minds of different cultures

To begin, we watched a video of different people using a social network called “FeelThat.” The “FeelThat” Network includes a device that a person would wear, allowing to them to send or receive emotions to and from other users who are also wearing this device. Through this device, one can sense another person’s feeling no matter where they are in the world. The device works by using advanced biological and neurological sensors, and relay messages to the other user. The “FeelThat” measures heart rate, blood pressure, amount of sweat on skin, and hormone levels. Similarly, the FitBit has already been invented, measures your biological functions, like heart rate and other factors similar to those used by the “FeelThat” Network. Devices like the FitBit make the possibility of sharing emotions through sensors, all the more real.  

Concerns I would have if this device was actually created, would be the effect on privacy. Contemporarily, keeping your life private is very difficult with all the social media that has been created. Thoughts and emotions are one thing that we can keep personal, just by simply not talking or mentioning about them. The “FeelThat” Network could potentially affect every aspect of privacy. Even though the network includes privacy settings, it is still possible that someone could hack the system and expose the user’s private emotions.  

Overall, I thought that playing the game was a positive experience and enjoyed interacting with different people. The concept for the device was very fascinating, but alarming to think that the particular invention could be made possible. I think that it was amazing how much this game connected to biology with the neurological sensors transmitting messages. Although this game relates to biology, one of the most relevant lessons I will take from this game, is being innovative during present times because we build the future. Another lesson that this game entails is that everything has consequences and to be careful about what you publicize because privacy is a gift.

Observing the Stages of Mitosis Lab

Title: Observing the Stages of Mitosis Lab

Purpose: Observe roots tips to determine how long cells spend in each phase of the cell cycle.

Introduction: Mitosis is a type of cell division that goes through the stages of the cell cycle: prophase, metaphase, anaphase, and telophase, in result of two identical daughter cells. The daughter cells produced in Mitosis have the same number and type of chromosomes as their parent cell. Interphase, which occurs in the cell cycle, is when the cell is doing its job and the DNA is replicating. Chromatin is not yet condensed into chromosomes during interphase, chromosomes are also not yet distinctly visible. During prophase, the cell membrane starts to break down and the chromosomes condense, but are not organized. In metaphase, the chromosomes line up along the cell’s equator while the spindle fibers continue to grow. Then in Anaphase, the chromatids are being pulled apart by the spindle fibers and are found on opposite sides of the cell.  Finally, the nuclear membrane starts to divide and form around each set of chromosomes. The cell splits and the two daughter cells are formed at the end of Telophase, Cytokinesis. Plants grow at their roots; the root cells are constantly dividing in order to grow. A root tip was chosen to be observed because it contains cells at different stages of the cell cycle, since each cell divides independently from other cells.

Materials:

  • Microscope
  • Prepared slides of onion root tip

Methods:

  1. Set up microscope. Start with low power objective in position with diaphragm open to the widest setting
  2. Place side of onion root tip on microscope and focus the microscope to get a clear view of the onion root tip. Focus starting with lowest power objective, then move to higher objectives once focused.
  3. Observe box-like cells arranged in rows.
  4. Identify what stage of mitosis each cell is in by appearance. Count how many cells are in Telophase, Anaphase, Metaphase, Prophase, then Interphase.
  5. Convert into percentages (Total # Cells/# Cells n Stage). Record Data

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Analysis: I included Quinlyn’s Data to show how my data differed and should be excluded from the total class average. The data I collected only included data from 1 cross section, whereas other students collected data from 2 or 3 cross sections, making the percentages differ. 2 to 3 cross sections samples provide more accurate data than data from only 1 cross section because more data allows for margin of error.  From the class average data, 81% of cells were found in interphase, 12.46% in prophase, 1.65% in in metaphase, 1.37% in anaphase, and 2.03% in telophase. Conclusion:

Conclusion: Most of the cells were found in interphase, which is logical because that is when the cell is doing its specified job.  Prophase has the second highest amount of cells in that stage because the cell is condensing long strands of chromatin into small coiled chromosomes, forming the mitotic spindle,  and breaking down the nuclear envelope. The stages of Metaphase, Anaphase, and Telophase are completed very quickly so the cell can finally split and continue to be productive and do its job. Within the class data, some errors could have occurred from  human error (miscounting the amount of cells) or having cross sections where the chromosomes were cut off and could not provide enough information. For my data particularly, the percentages of 1 cross section differs from the percentage of  3 cross section averages. I had to disclude the observations found from the first cross section I examined because the slide was unclear and the nuclear envelope and chromosomes were not visible. It is unnecessary to include data from unclear onion root tip sample slides because they would not provide enough usable information. Each root tip sample is a cross section, so it is possible that the chromosomes could have been cut and only found in the other cross section half.

Evidence that supports that mitosis is a continuous process rather than a series of events is that each cell is hard to differentiate between each stage because it is constantly changing.  The onion cell had 4x chromosomes at the end of interphase because DNA is doubled and is preparing to split later on. At the end of telophase, there are two cells, each with 2x chromosomes.  

After meiosis, there would be 1x chromosome in each sex cell because the cells start with 4x, then divides twice throughout the process (4 sex cells with 1x chromosomes).  If this onion would complete the process of sexual reproduction, 2x chromosomes would be found in the zygotes that are produced, because of a sperm(1x) and an egg(1x) create a zygote.