In Sickness and In Health: A Webquest

This web quest continues our study on genetics and reproduction in my biology class. Below is a human pedigree that I created for a couple's family. You can find the information on the the couple's family in the link below:

http://www.sciencecases.org/sickness_and_health/sickness_and_health.asp

The couple is Greg and Olga, as you have read, both of their families have a few genetic diseases. To see if the couple could have a normal child, I have created the human pedigree below. To be clear in my pedigree. F stands for Father and M stands for Mother. 

Based on this pedigree, I can assume that autosomal dominant disorders skip generations. As you can see, Olga's uncle(who has hemophilia) married her aunt on her father's side who is unaffected by any type of genetic disorder. They had two children that were also unaffected by any type of genetic disorder. However, one of these two children married and had a son, that son had hemophilia just as Olga's uncle does. This is a clear sign of hemophilia skipping generations. Also based on that information, I can assume that Greg or his Mother could be carries of the gene that causes myotonic dystrophy. If Olga's uncle had children that showed no sign of hemophilia and then passed hemophilia onto their son, then one of the parents(related to Olga's uncle) must have passed hemophilia onto their child. Based on that information, it is very possible that Greg or his mother are carriers of the gene that causes myotonic dystrophy. It is obvious that Greg's aunt and uncle are homozygous for the myotonic dystrophy gene. It has been passed down through generations, skipping or not, it still has been passed down, and could possibly pass down to Greg and Olga's children. Greg and Olga's child is also at risk for Factor VIII Difiency, since Greg's brother has that disease. The possibility is at a 25%.

Because Myotonic dystrophy symptons sometimes do not show up until after age 50, it is very likely that Greg's cousin has inhertited the MD gene. The possibilty is a 50% percent chance.

Mitosis Lab

In my biology class, we did a lab on mitosis to evaluate the percentage of cells that are in interphase, the ones that are in prophase, the ones that are in anaphase and the ones that are in telaphase. 

Mitosis is the division of cells, and in this division of cells are 5 phases(as listed above). Here is a brief description of each:

Interphase: This is the phase that begins the cell's division. About 90% of the cell's time dividing will be spent in this phase. In this phase, the DNA synthesizes, once the cell has synthesized the proteins, the cell will continue to increase in size. 

Prophase: In this phase, the chromosomes will condense into discrete chromosomes. The nuclear envelope also break here and and spindles to form at opposite poles. In this phase, the chromatin fibers will form into chromosomes that have chromatids that are joined at the centromere. 

Metaphase: This is the phase where the spindle fully develops and the chromosomes align at the metaphase plate. Also, the nuclear membrane disappears in this phase. 

Anaphase: At the beginning of anaphase, the sister chromatids separate and move to opposing ends of the cell. Spindle fibers inside the cell begin to lengthen in preparation for telephase. By the end of anaphase, each pole will contain a complete set of chromosomes.

Telaphase: In this phase, the chromosomes are cordoned into new nuclei in emerging daughter cells. At this time, the spindle fibers will continue to lengthen. The new nuclei forms at opposing poles. Cromatin fibers form from chromosomes uncoil, this is the end of mitosis.

In my biology class, we got to look at these 5 different phases physically through a microscope. I thought it was really interesting, it was nothing like I envisioned it to be. Also, looking at pictures provided online by my teacher was really different from looking through the telescope.

Onions have much larger chromosomes than most plants, so it is easy to see how a cell divides in the process of mitosis at the root of the onion. Our class separated into groups to do this lab, at first we studied a small field online. A cell is at rest in interphase; we recorded how many cells were in each phase. We used that data to make percentages and create charts to help us compare data to an actual onion root that we, ourselves will study under the microscope. 

 This is a chart that I created for the online field that we studied. The chart tells us that 55.5% of the cells were in interphase, 27.8% of the cells are in prophase, 2.3% of the cells are in metaphase, 5.5 of cells were in anaphase, and 2.7% of the cells are in telophase. As you can see, most of the cells were in interphase in the field studied, and most cells were not in metaphase. Also, my recordings did not come out to a complete total of 100%. With some help from my teacher, I was able to create a pie graph that came out to a total 100% (below).

We studied fields of cells in the apical meristem of the onion root, we looked under the microscope and recorded how many cells were in each phase, just like we did for the online field. Below is the data recorded:

I know its a little hard to read. Just to be clear; 96% of cells are in interphase, .02% of cells are in prophase, .009% of cells are in metaphase, .006% of cells are in anaphase, and .008% of cells are in telophase. To compare percentages easily, here is a pie graph:

As you can see, you can hardly see any other of the phases because interphase is so dominant. Because we used an actual field, the numbers are a lot higher than the online field. Comparing this field to the online field, there are is an obvious similarity. Almost all of the cells are in interphase, or at a sit still. Also, the number of cells in metaphase is the smallest. Below is a picture of what the apical meristem of the onion root looks like, this is not what I studied.