You have what appears to be quite a good project in front of you. I guess all I can tell you is how I would approach the decision of which cell to pick.

First, if I had a particular interest in medicine, I might gravitate to a relevant cell type.  For instance, if I was thinking of becoming an eye doctor, I might want to pick one of the cells in the eye and look at how it turns light (photons) into images in the brain.  Or, if I had sickle-cell anemia, I might want to do a red blood cell.  (ask your teacher before taking on a red blood cell, as it is actually 'blebbed off' a mother cell and therefore does not contain the organelles of other cells - some do not consider it a true cell)  Or, if I had a friend with epilepsy, I might want to do a nerve cell (which are very weirdly shaped).

But, if it was wide open, I'd look to see how much information I could get on different cell types.  I'd Google 'plant cell types' and 'animal cell types' in both the web and images search features.  As important as the AMOUNT of information is how much of that information was geared toward a student.

Then I'd see if one cell type had a good amount of information AND if it did something that interested me. A cell's structure is very much related to what it does.  A heart cell has a lot of actin and myosin in it's cytoplasm and it has a lot of mitochondria, since these organelles make the energy needed to pull the actin and myosin fibers.  Each cell acts in unison so that the heart 'beats'.  A white blood cell has lots of plasma membrane so it can capture bacteria in the body. These cells also have the ability to move from the blood stream through the tissue to the site of infection -this is called 'chemotaxis'.  Once a white blood cell has engulfed a bacterium (in a phagosome), it bombards it with destructive enzymes by fusing the phagosome with 'granules'.  Granules are organelles that are little sacs containing these enzymes - by storing them in the granules, the white blood cell protects itself from these destructive enzymes.

So, long story short, I'd Google the basic cell types and see if something caught my fancy.  Because every cell has an interesting story to tell.

Thanks for asking,

Dr. Pat

Dr. Pat,

Ok, that sounds pretty good. Wow, thank you so much, I had no idea how I could learn about the different cells and how to choose them.  I'm really glad that you sent me that email back because I know that a lot of sites like yours just send the same message not really explaining that much, just the basics, to everyone who emails them.  I'd just like to say thanks, you've helped me a lot over one email.

In fact, I have even picked a cell.  It is called a Parenchyma plant cell.  It is unique, and my science teacher didn't even know what it was!  He was glad though, because now he doesn't have to go through the long presentation about a cell he already knows about.  Now, he will want to listen...which gives me a little advantage!

Thanks so much once again: student in need no more

Thanks,  Amanda

Another structure found in leaf cells is a chloroplast.  That is the organelle that contains the chlorophyll, which makes leaves green and absorbs sunlight energy so the plant cell can make sugar.

Many plant cells also contain an organelle called a vacuole, which is absent in animal cells.

Thanks for asking.
Dr. Pat

Thank you so much!  I had no clue.  I didn't think you would actually send me an email back!  Thank you so much, now I know what site to go on for science questions! 
Thanks again, -Amanda

As for introducing cells to a second grader - I think the delivery of our cell information is 'story' oriented enough that a student this young could get something out of it. And, if you walk them through alternate descriptions of the information that seemed too tough, they could get the concept.

I think that, unfortunately, students often look at science as having to memorize a list of facts. This approach requires a certain type of mental maturity. But, the easiest way to learn is by absorbing the central concept and then 'hanging the facts' around it. That is the approach we have tried to take with our website.

The most basic central concepts in cells are:

All living things on earth are constructed with cells - much like building with legos. The simplest types live as single cells, while more complex, like cats and dogs and trees and dandelions and humans have many many many cells. There are two types of cells based on their internal structure - bacteria that have all the essentials tossed together inside the cell - and plants & animals that organize the essentials in internal compartments called 'organelles'.

More complex concepts are:

There are different cell types in one plant or one animal, all with the same DNA. These different cell types (heart, liver, root, leaf) have different assortments of organelles that allow the cells to do different jobs. For instance, a heart cell must use a lot of energy to contract or 'beat', thus it requires a lot of mitochondria to create that energy.

I hope this helps. Our relevant pages are: http://www.eurekascience.com/ICanDoThat/bacteria_cells.htm

http://www.eurekascience.com/ICanDoThat/animal_cells.htm

http://www.eurekascience.com/ICanDoThat/plant_cells.htm

Thanks for asking,
Dr. Pat