The Forensics Quiz

The bullet went in a downward angle that was 45 degrees and the entrance was the left lateral side 1 cm above the third rib and the exit site was 5 cm above the belly button in the umbilical region. The 8th rib was fractured, and fragments of the bullet are found traced to the final exit wound.

He was mostly likely shot in the back with the gun pointing down and they shot him in the left at an angle. The passage for the left third rib region to the 8th rib on the right would have fatally injured organs.

It would have most likely hit the heart, stopping it. This bleeding from the heart would have killed him instantly. The bullet when it hit and fractured the 8th rib, could have caused shards of the bullet to come off. 

The other three plausible alternatives to why he died could be that he suffered a bullet wound to the stomach, which is also in the umbilical region but then the stomach acid would have been released and present in the body. The second plausible alternative is that it might have hit the small intestine which is also in the umbilical region, but it entered too high up and would have had to exit lower in the front. The third plausible explanation could be that it hit the liver causing failure however the liver is far over in the right hypochondriac region.

Week 3: Growing Organs and Stem Cells

Can stem cells function with stress and how is cancer related?

Tanya and I researched this question and discovered that in an experiment on mice they increased environmental stress factors for example reduced the presence of sulphate. This environmental stress factor made the cells function less well and made it prone to mutations. We know that if we increase cells that are mature into iSPCs these cells are still as however old they were before reengineering. This means they reach the hay-flick limit faster and they are also more prone to mutations on genes. This is why 1/3 of the mice showed developments of cancer because their cells, which were more prone to mutations, developed mutations on the proto-onco genes that regulate the checkpoints for mitosis. Mitosis was essentially left open ended because the checkpoints didn't function because of mutations.

We watched a Ted talk which was done by this researcher Anthony Atala. He and his team discovered a groundbreaking treatment. When a tissue is damage essentially they take cells from healthy tissue and generate them outside of the body and insert them with a scaffolding. They condition these tissue cells to do functions before like expand and contract so they are useful, which is really cool. They can also instead of creating a new scaffolding. They can take an organ for another human and wash it off it's cells with detergent and then coat it with new cells from the patient and it will be least likely to reject.

Week 2: Stem Cells

Stem cells are body cells that have been made to revert to an embryo-like state without eggs or embryos. This reversal can rejuvenate cells so therefore they can be very productive in curing diseases. There are fluorescent markers on the cells which indicates pluripotency. Pluripotency is the cell's ability to develop any type of tissues. In 2006 the formula that creates induced pluripotent stem cells (iPSCs) was released. These can come from skin cells. Typically cells in the body become more specialized as they age in differentiation. They are only un-specialized for a short amount of time in the early stages in the embryo this is (pluropotent). In late embryo stage cells can already reach specialization for a specific tissue area such as in muscles which is called multipotent. Mature cells can be reprogrammed to be more "immortal". The older approach to this was to use manipulations in adult cells to trick it to behave like an embryonic cell. This older approach is "cloning" which means to insert genetic material from an adult cell into an egg cell, that has removed DNA. This has been successful with a case of a sheep (Dolly )but hasn't been successful for humans yet. You can produce iSPCs with four genes and this can reprogram using retroviruses as "vessels".  Some cells can not become iSPCs though because important genes can not always be turned on. Retroviruses are sometimes a problem because it can damage DNA when it is trying to reprogram. Adneoviruses could be used as a vessel because they remain for a short amount of time and only the amount of time that is really needed for the converting. These iSPCs can cure sickle cell anemia in mice now. However it has not been successful to use them to replace an organ yet.

Semester 2: Week 1- Cancer.

Cancer can develop when cells do not reach their Hayflick limit. They do not reach their Hayflick limit which is when cells stop dividing. This means that cancerous cells are constantly dividing. They keep going thru processes of mitosis. This means that lots of cells will develop. Cancer can also grow when the cells attach to veins and get glucose from these veins to increase their production. Chemotherapy stops processes like mitosis so cancer cells won't grow. There is a also a P53 tumor suppressor gene in our DNA that sometimes doesn't work.

Day 26: The Cell Cycle

The Cell Cycle has five stages.

The first stage is interphase in the G2 phase it is when the nucleus is really dark. DNA replication occurs in this phase using the enzymes previously talked about which is Helicase, RNA primer, DNA poly III, and DNA poly I.

After interphase the next stage is prophase, prophase is when the first sign of division is indicated. This part is a little more obvious the chromatin has been condensed into lots of chromosomes. Each chromosome is composed of two chromatids joined at the centromere. The chromatids will thicken and shorten and the it will attach to forming spindles. The spindles are made of microtubules. The microtubules will move to poles kinda of like magnetic poles.

Metaphase is the third stage and all the chromosomes move to the center and line up.

Anaphase is when the centromeres divide and sister chromatids move to opposite ends.

Telophase is when the spindle fibers disappear and the nucleus begins to reform and the chromosomes de-condense.

Cytokinesis is the final stage and is when the cells divide completely and have their own membranes. The result is 2 daughter cells that have identical genetic information to the parent cells.