MITOSIS
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Before we get started with mitosis and meiosis, let's have a quick review of cell types.
This is important because mitosis and meiosis only happen on eukaryotic cells!
Let's see the difference between eukaryotic and prokaryotic!
This is important because mitosis and meiosis only happen on eukaryotic cells!
Let's see the difference between eukaryotic and prokaryotic!
We have been talking about mitosis a LOT. Every plant that grows, everything that heals, it's all because of mitosis.
The suspense is killing me! Let's break it down!
Mitosis is the basis for most of our body's growing and healing processes. Without mitosis, we would never be more than a single cell organism!
Let's take a look at skin cells, for instance. A snake sheds its skin all at once, but you are always shedding cells from the outer layer of your skin. This happens because older cells are constantly being pushed to the surface by new cells that are reproducing below them. In about 28 days, your entire outer layer of skin is replaced by new cells. Use the equation below to determine the number of times that you have changed your skin in your lifetime.
The suspense is killing me! Let's break it down!
Mitosis is the basis for most of our body's growing and healing processes. Without mitosis, we would never be more than a single cell organism!
Let's take a look at skin cells, for instance. A snake sheds its skin all at once, but you are always shedding cells from the outer layer of your skin. This happens because older cells are constantly being pushed to the surface by new cells that are reproducing below them. In about 28 days, your entire outer layer of skin is replaced by new cells. Use the equation below to determine the number of times that you have changed your skin in your lifetime.
Right now, cell reproduction is taking place in your body as it produces thousands of new cells. Different types, such as red blood cells, skin cells, and cells that line your digestive tracts, are continually being made to replace older cells.
Not all at once! And not at the same rate! In fact, different cells of the body have different life spans. For example, cells of the colon live for a few days. Skin cells live for a few weeks. Red blood cells last for a few months, and some white blood cells last more than a year.
What would happen if the cells reproduction cycle matched on all cells of the same type -- if their cycles started and ended on the same day?
Cell reproduction is also how you grow and how your body heals! Every time you get a cut or a scrape, you need cell reproduction. Every cell in the body reproduces!
Check out this healing scab:
Not all at once! And not at the same rate! In fact, different cells of the body have different life spans. For example, cells of the colon live for a few days. Skin cells live for a few weeks. Red blood cells last for a few months, and some white blood cells last more than a year.
What would happen if the cells reproduction cycle matched on all cells of the same type -- if their cycles started and ended on the same day?
Cell reproduction is also how you grow and how your body heals! Every time you get a cut or a scrape, you need cell reproduction. Every cell in the body reproduces!
Check out this healing scab:
So, we use cell reproduction for a lot of different things; but what if you had only one cell? Cell reproduction would be even more important. It becomes an essential part of an organism’s life cycle. For single-celled eukaryotes such as amoebas, the process of making new cells is how they produce new offspring. For us more complex eukaryotic organisms, cell reproduction has many different purposes.
But all eukaryotes use the same mechanism:
But all eukaryotes use the same mechanism:
MITOSIS
During mitosis, there are different phases which can be identified in the microscope.
Please note: Interphase and cytokinesis are not actually phases of mitosis, but are a part of the cell reproduction process. Mitosis is the action of replication itself.
Interphase: This is the chill phase; it's not mitosis yet. This is the phase where the cell is getting ready for division. While the cell grows, the organelles are duplicating, and so is the DNA. Too bad you can't see it, because in this phase, the genetic material is all relaxed, like a full bowl of noodles.
Prophase: The DNA tightens its curls! This makes them look much shorter. Everything gets condensed, and now you can see them. This is the phase where the nucleolus disappears. The duplicated centrioles move to the poles of the cell.
Metaphase: Chromosome pairs line up in the middle. They are kept in place by thin spindle fibers that form from the centrioles.
Anaphase: The spindle fibers contract, and the chromosome pairs are finally separated; each side gets a copy of each chromosome.
Telophase: The cell wall starts pinching in the middle, and new nucleus starts to form. A nucleolus reappears on each side.
Cytokinesis: This is the actual division of the cell into two new cells. This brings us back to interphase.
The cell cycle involves growth, development, and then division. In which stage does a cell spend most of its life?
Please note: Interphase and cytokinesis are not actually phases of mitosis, but are a part of the cell reproduction process. Mitosis is the action of replication itself.
Interphase: This is the chill phase; it's not mitosis yet. This is the phase where the cell is getting ready for division. While the cell grows, the organelles are duplicating, and so is the DNA. Too bad you can't see it, because in this phase, the genetic material is all relaxed, like a full bowl of noodles.
Prophase: The DNA tightens its curls! This makes them look much shorter. Everything gets condensed, and now you can see them. This is the phase where the nucleolus disappears. The duplicated centrioles move to the poles of the cell.
Metaphase: Chromosome pairs line up in the middle. They are kept in place by thin spindle fibers that form from the centrioles.
Anaphase: The spindle fibers contract, and the chromosome pairs are finally separated; each side gets a copy of each chromosome.
Telophase: The cell wall starts pinching in the middle, and new nucleus starts to form. A nucleolus reappears on each side.
Cytokinesis: This is the actual division of the cell into two new cells. This brings us back to interphase.
The cell cycle involves growth, development, and then division. In which stage does a cell spend most of its life?
And now, we sing!!!
WHEN MITOSIS GOES WRONG
Sometimes, cell division goes awfully bad. This is caused by some type of change inside a damaged cell. These changes can cause the cell to stop dying, and just keep multiplying; sometimes, the division mechanism is also broken and the cell divides very quickly.
This uncontrolled division and growth is what we call cancer and tumours.
As you can imagine, all this fast division takes a lot of nutrients, and so cancers and tumours make a person weak because of this. They also squish healthy organs, nerves and other structures, causing pain and discomfort.
But maybe the worst thing about cancer is that these cells just don't work right. They don't do the jobs they are supposed to. And they even create their own blood vessels, to ensure they steal as much nutrients as possible.
To learn more about specific types of cancer, let's do some detective work!
This uncontrolled division and growth is what we call cancer and tumours.
As you can imagine, all this fast division takes a lot of nutrients, and so cancers and tumours make a person weak because of this. They also squish healthy organs, nerves and other structures, causing pain and discomfort.
But maybe the worst thing about cancer is that these cells just don't work right. They don't do the jobs they are supposed to. And they even create their own blood vessels, to ensure they steal as much nutrients as possible.
To learn more about specific types of cancer, let's do some detective work!
Mitosis and Cancer Analysis
Cancer and tumours can happen in any part of the body that has cells. Around the classroom, there are six different types of cancer. You will find some hints hidden as well. What cancers are these? Based on their description, can you find the answer in the internet?
Fill in the worksheet with all the information you find. There are also six possible cures for you to examine; which cures should you use for each cancer? The answer is not always the same. It turns out that the treatment will depend a lot on the kind of cancer, location and stage it is in.
Fill in the worksheet with all the information you find. There are also six possible cures for you to examine; which cures should you use for each cancer? The answer is not always the same. It turns out that the treatment will depend a lot on the kind of cancer, location and stage it is in.
Hello future Mrs. J! Download the following papers. Set them up in different stations around the room. Students must move about to find their clues. Some of them might need internet research! Love, past Mrs. J
Cancer Types
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Cancer Cures
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Hints and Worksheet
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Some ways to avoid cancer are lifestyle choices, prevention and screening.
- Eat healthy – preservatives and processed foods can help feed defective cells
- Reduce stress
- Keep a healthy weight
- Exercise
- Limit alcohol
- Don’t smoke or stay in the Sun without protection – chemicals that damage cells also increase the risk of mouth, throat, tongue and lung cancer
- Don’t stay in the Sun without protection – UV Radiation is known to cause damage to skin cells
- Early screenings – if something does not look right (lump, discharge, mole), go to the doctor immediately. While these don’t avoid cancer, they can help treatment at an early stage and avoid bigger issues.
Video and Quiz!
Watch the video below and complete the attached quiz.
| video_quiz_cell_rep.docx |
