Mitosis Steps - Continued
Now you've memorized the order of the steps, let's find out more about them.
Interphase
The cell spends most of its time in interphase. This is when the cell is not dividing. The DNA is all stretched out, making it invisible under a microscope. A cell will spend most of its life in interphase. This doesn't mean a cell is resting though. It is replicating the DNA, organelles and other vital parts. It is growing, gaining nutrients, adapting to the environment and doing most of what we call living.
An easy way to remember this name is to think of the DNA at a party. It's all spread out, relaxed, and anxious to interact with other DNA. So, when you hear INTERPHASE, think INTERACT.
Prophase
Prophase is the start of big changes in a cell. When the nucleus is ready to divide, the DNA starts coiling up with the help of proteins. They wind up tighter and tighter until they can't wind anymore. At this point, they are visible under a microscope. The replicated DNA resembles X's. Each half of the X is a chromosome, and they've paired up with their twin to make sure each daughter cell will get a copy of each chromosome.
When you think PRO phase, think of a pro football player. Think of him wearing a big X on his jersey. Now imagine the coach getting him all wound up before a pro-bowl game. Perhaps the coach is showing a playbook diagram. See all those Xs in your mind? Remember, during PROPHASE - chromosomes look like Xs.
Metaphase
Mmmm, metaphase is probably my favorite phase. Once all the chromosomes are wound up and paired up, they line up in the middle of the cell. All those little Xs are along a central line right in the middle of the nucleus. This is handy because if they're in the middle, it's easier to get the right number of chromosomes into each daughter cell.
When you hear METAPHASE, spend an extra second saying the letter M. Mmmmm, isn't that nice? M is for Meta, and M is for Middle. By the way, for you lovers of Latin, META means MIDDLE. Mmmmmmm Metaphase, mmmmmmmmm middlephase.
Anaphase
This is a sad tale of woe. There once was a girl named Ana. She was pretty and exciting, but she had a nasty game she liked to play with people's lives. She liked to break up friendships. She would date a boy for a while, break up with him for no reason, and then date his best friend. Once the two of them hated each other, she would dump the friend and move on to another pair of buddies.
This is a horrible story, but I hope it helps you remember ANAPHASE. During anaphase, the chromosomes are separated from each other. Ripped apart. They no longer form Xs, but halves of Xs. They bid farewell to each other and start heading their separate ways.
There is a happy ending though. For the chromosomes, each will live to replicate again, and for the girl named Ana, she settled down eventually, got married and is also replicating.
Remember, ANAPHASE is just like ANA's PHASE.
Telophase
After a chromosome is broken, each half is called a chromatid. During telophase the chromotids travel to opposite sides of the nucleus. They're just completing what Ana started, and they end up a great distance away from their twin.
You're already familiar with the word TELO, whether you know it or not. You watch television and have talked on a telephone. Tele and telo both mean the same thing in the Latin language. TELO means FAR, or DISTANT. You may have heard of a telegraph. The word graph means writing, so a telegraph is distance-writing. See if you can decipher the meaning of other tele-words.
Remember, TELO is distant. Put that with PHASE and you have TELOPHASE, or the time when chromatids are at a distance.
Cytokinesis
"Woah, Miss Lowe," you may be saying, "you never said anything about this before!" Very good, you recognize new information. Once the chromosomes have split and the pieces are separate, the cell needs to become two different cells. It pinches off in the middle and a new membrane forms between the two halves Once this happens, there are two different cells, identical to the one which started out the process. The DNA in each cell uncoils and goes into interphase and the whole thing starts over again.
For those interested, the word CYTO refers to the cell. Think cytoplasm, the liquid in the cell. KINESIS means to move. There is indeed a lot of moving going on as one cell becomes two.
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