Today I am supposed to explain mitosis.  Mitosis is the process that eukaryotic cells perform to divide body cells and is broken up into six phases.  Interphase is the time when the nuclear membrane hasn't broken down and the DNA is still in loose strands.  Then the DNA thickens into chromosomes and the nuclear membrane breaks down.  This is called prophase.  Once the chromosomes have thickened they bundle up tightly in the middle and the spindle fibers form then attach themselves to the chromosomes, which is the third phase called metaphase.  The next phase is called anaphase.  Anaphase is where the spindle fibers pull the sister chromatids away from each other, and then disintegrate once the chromatids are separated.  Then comes telophase which is basically the beginning of the last phase which is cytokinesis.  It is where two new nuclei begin to form.  Then cytokinesis is the last phase where there are two new cells, that are exactly copies as the parent cell.

A bacteria cell is very simple, but still has a well developed structure.  Bacteria is prokaryotic which means that they do not have a nucleus.  They do have a nucleoid though which is a central region that holds the DNA, but is not bound by a membrane.  Bacteria cells perform all the same functions as every other kind of cell, including mitosis, meiosis, and DNA replication.  In fact every type of living organism replicates DNA the same way which leads scientists to believe that every living thing is related.  

Plant cells are a type of eukaryote which means that they do have a membrane- bound nucleus.  They are like animal cells, but have a cell wall and mitochondrion which animals do not have.  Also, animal cells have a very small vacuole, but plant cells have vacuoles that take up about 90% of the cell.  One other difference between plant and animal cells is that plant cells have more of a rectangular shape whereas animal cells have a round shape.  These are the main differences between animal,  plant, and also bacteria cells, which have very obvious differences.

The edible cell was a group project we did in science class.  We had to build a cell with all its organelles using only edible materials.   Each person was responsible for bringing some of the things that we would use for a certain part of the cell, and then we brought it all in to class and put it together, then ate, after it was graded of course.

  This project was designed to help us learn more about cell structure since that was what we were studying at the time.  I think this is a good way to help students learn about the structure of a cell, because you actually have to put it together and see what it is supposed to look like.  Also it is fun, and keeps you interested, whereas just reading a textbook can put you to sleep. So that is why I think this project was effective, and would definitely advise the seventh grade science teachers to continue it.

The topic for today is to pick three cell parts and describe what each of their functions is.  So the first two parts of the cell (organelles) that I will describe are the chloroplast and mitochondrion.  These organelles work together in a plant cell to make food for the cell.  The chloroplast uses the energy of the sun to create food in the form of glucose.  Then the glucose goes to the mitochondrion which breaks down the glucose to realease the energy from it.  This is how a plant cell gets its energy.  In animal cells, the mitochondrion is also used to break down food, but the cell doesnt get food from the sunm, so there is no chloroplast.

The other organelle I will describe is the vacuole.  A vacuole is like a storage tank and holds most of the cells water and other materials.  Animal cells barely have a vacuole, but in plant cells the vacuole is huge.  If a plant's cells didn't have a vacuole the plant would shrivel up and die.

In our science class there are rats and during the first quarter they had babies.  We started measuring and weighing them on the third day of their lives.  The first time we weighed our rat, it weighed 7.6 grams, it's tail was 20 millimeters, and the circumfrence of it's head was 50 millimeters.  We also measured them on the sixth, ninth, thirteenth, and forty-fifth day.  The ratio between the tail length and the circumfrence of the head was always changing and I kind of saw a pattern.  Evey time we measured the rats, the length of the tail got closer to the circumfrence of the head, which meant that the tail was growing faster than the head.  By day thirteen, the tail was 50 millimeters long and the head's circumfrence was 62 millimeters.  But after day thirteen we didn't measure them again until day 45.  By this time the tail had grown to 110 millimeters,  and the head was 75 millimeters.  So as you can see the tail was growing much faster than the head was.

Science during first quarter has been a lot of fun and full of cool labs where we learned a lot.  We have done labs about air pressure such as the egg in a bottle experiment, we have looked at how sugar affects the mass of and object when we did the gum lab, and we have looked at things up close under the microscope like when we looked at onion cells.  These were all fun and interesting, but my favorite thing that we did in science was study the development of the baby rats that were born in our classroom.  There are a ton because there are three female rats.  We basically got to see some of them being born which was cool. Then we started weighing and measuring the rats every few days to see how they grew.  It has been a lot of fun and now, weeks later, the babies are ready for adoption.  This was my favorite part of science during this quarter.

Today, for my science solution, I will be explaining the difference between a  A prokaryotic cell does not have a nucleus or any organelles.  It is a primitive and is common in bacteria.  Prokaryotes also have ribosomes and are about one tenth of the size of a eukaryotic cell.  A eukaryotic cell has a nucleus and organelles.  They are much more advanced than prokaryotic cells and are found in plants and animals.  THey are about ten times the size of a prokaryote.  These are the main differences 

Cells are very confusing to me but I will try my best to explain why you cannot feel cellular activity even though you know your cells are alive and functional.  First of all, you know that your cells are working because you are alive.  If your cells weren't working you would not be alive.  Cells are what make up all the organs of your body and if they weren't there then your body would not be able to funcion.  And that is how you can know that your cells are alive and functional.

Finding the volume of an irregular shaped object is much easier than it may sound.  All you have to do is use the displacement method.  The displacement method is very simple.  All you need to do is have a measured container of water.  Then you put the object in the water and however much the water rises is what the volume of the object is.  For example, lets say you are trying to find the volume of a small rock.  You have a container of 500 milliliters of water and when you put the rock in, the water rises to 600 milliliters.  By doing this you know that the volume of the rock is 100 milliliters because the water rose 100 milliliters when the rock went in.  This is called the displacement method.

In science we are currently learning about the effects of air pressure.  To learn this we have done some interesting experiments.  One of the ones we did was called the eggsperiment.  During this experiment we had to try to get a peeled hard boiled into a bottle.  At first the egg could not go into the bottle becaus the air pressure inside and outside of the bottle were the same. In order to get the egg into the bottle, you have to put a piece of burning paper into  the bottle.    This changes the air pressure allowing the egg to go in.  To get it out you have to flip the bottle over so that the egg is at the top.  Then you have to blow as hard as you can into the bottle and the egg will come out.  And that was the eggsperiment.