Forensics Quiz

It's funny how this case happened on Thompson creek. Should probably stop having practice in that area if we don't want to end up supine on the ground...

The bullet probably entered the person's left lung, went through his heart since it's going in a 45-degree downward angle. It then probably went through the person's liver and hit the 8th rib on the right side since the right 8th rib is fractured. Since the bullet exited 5cm above the belly button, it probably reflected after it hit the rib and exited through the umbilical region in the frontal plane. The cause of death is shot through the heart. 

The person could have died from damage in lung but the bullet went in a 45 degree downward angle, which means it has to go through the heart, so the person would die from the shot to the heart before he die from damage of lung. He could have die from loss of blood because the bullet hit his aorta, but the bullet entered above the third rib and went down, which is lower that the aorta, so that possibility is ruled out. The bullet could have went through the left lung and heart and exited above the belly button directly, but the person's right rib was broken, so the bullet has to be reflected by the rib.

DE-EXTINCTION

     The term de-extinction refers to bringing back extinct animals with stem cell technology. Theoretically, if scientists have body tissue from an extinct animal, they can clone this extinct animal.
     The first method would be extracting DNA from the animal's cell and transfer its DNA into another kind of animal's egg cell, which has its nucleus taken out. After an electric shock, this egg will start dividing and form an embryo, which will develop into the extinct animal.
     The second method is comparatively new, which is to stimulate the extinct animal's cell to change back to an embryo state -- stem cell, and it will develop into an embryo.
     However, this technology is not mature. Scientists have had successful experiments, but the produced animals always die shortly after birth because of complications, especially lung defect.    
     A lot of people are against de-extinction and argued that if this technology matures, scientists will be able to bring dinosaurs back to life and what was depicted by Jurassic Park will happen in real life. Additionally, people should not play god.
     Those who are in favor of de-extinction claim that it is only possible to clone animals that died out within a few years because there is not adequate body tissue of extinct animals from earlier times. They also state that people are already playing god by destroying animals' habitats and endanger their existence, so why not play god and bring them back?
     Nevertheless, cloning is not the way to solve extinction because people cannot produce mass amount of clones and the clones will have an extremely small gene pool, which will not help produce robust offsprings. Additionally, if people do not improve the environment these clones live in, they are still going into extinction.

The Island

1. Stem cells can produce all kinds of somatic cells. As a result, one can use stem cells to produce somatic cells and body tissue for patients who need transplantation.
2. In the movie, people donate their stem cells to produce clone of themselves so that when they need organ donation, they can receive the organs from their clones.
But, how were the clones born to be in adult forms? Even if it is clone, they need to be born as a baby and grow up right?
3. If human stem cells are allowed to be utilized, they can be leaked out, and people might use the stem cells to produce fetuses and sell them.
4. I don't think people need to make clones in order to attain organs. Can't they just produce a certain kind of body tissue with stem cell? For people who can't pregnant, can't they just donate their stem cells to make sex cells and produce a baby? They don't really need a clone to give birth to the baby. Why do clones have to have emotions in order to produce adequate organs anyways?

Stem Cells

Stem cells are the cells that reside in an embryo. They can generate any type of body cell and make any type of tissue, so they are sort of like the fountain of youth... There are two kind of stem cell. The first kind is called adult stem cells and they replenish different types of cells within a tissue. For example, blood stem cells regenerates 12 types of blood cells, and skin stem cells regenerate skin and hair. The second one is the kind one finds in an embryo, called pluripotent stem cell. Pluripotent stem cells can be planted in different environments and generate different cells. For instance, if a patient's heart tissue is damaged by a heart attack, one can plant pluripotent stem cells in his heart and the stem cells will generate heart cells to mend the damaged heart tissue. However, mammal cells cannot dedifferentiate, which means the pluripotent stem cell that can make all kinds of cells cannot be naturally generated from body cells. Nevertheless, there are three ways to make this happen:
1. Cloning
Scientists can inject the body cell genetic material into an egg, which had its DNA taken out. The egg will then develop into an embryo from which pluripotent stem cells can be extracted. Whereas, this method can not be used on human cells because it causes legal issues, and for some reason, it hasn't succeeded yet.
2. One can turn on the genes, which are normally active in only embryonic cells, in adult cells. In order to achieve this, one can use retrovirus as a vehicle to ship reprogrammed genes into adult cells and produce iPSCs (induced pluripotent stem cells). However, a lot of iPSCs are not properly made because  the genes are not properly turned on. As a result, these inadequate iPSCs cannot pass the pluripotency test. (1. Expose iPSCs to different environment and check if they can generate different types of cells. 2. Inject iPSCs into a mouse's skin and check if a tumor can be formed. 3. Inject iPSCs into an embryo and check if the iPSCs help embryonic development.) A disadvantage of this method is that the retrovirus and the reprogrammed genes can be inserted in the wrong place and produce cancerous cells.
3. Expose body cells to chemicals and turn on the genes that are active in pluripotent cells.

Stem cells has a lot to do with my research in treatments for Leukemia. The major treatment of Leukemia is stem cell transplantation. one extract the patient's blood stem cell before the patient receives chemo or radiation therapy and plants the blood stem cells back into the patient's body. The blood stem cell will make healthy white blood cells that kill the cancerous blood cells.

Cancer???!?!!!!!!

The reason why people don't get cancer all the time is because there's Hayflick limit. Hayflick limit limits the amount of time a cell divides. On the end of chromosome, there's something called a telomere that is made of CG repeats. Telomere doesn't code for anything. It only gets chopped away each time cell division takes place. It gets chopped away on the lagging strand because after RNA Primase makes RNA Primers from 3' to 5' and DNA is filled in, Ligase changes RNA primers into DNA except the last one. That's how it gets cut off. In cells like blood cells that need to constantly divide, they have an enzyme that is called telomerase. Telomerase adds telomere sequences to the end of chromosomes therefore enable cells to keep dividing.
Proto-oncogenes are normal cellular genes code for proteins that stimulate normal cell growth and division. However, they may become excessively active and mutates into Oncogenes, which cause cancer.
Tumor-suppressoe genes encode proteins that inhibit abnormal cell division. Nevertheless, they may decrease and cause cancer.

The formation of cancer starts with a malfunction cell that keeps on dividing. All the cells it produces will clump together and produce more cells. Blood veins will be drawn to the spot and provide ATP for the cancer cells. These cancer cells might enter blood veins and be transferred to other parts of the body.The chemo treatments are designed to stop processes of the cancer formation.