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.

Cell Cycle

Last class we learnt about cell cycle:

1. Interphase

---G1:  Normal growth

---G1 Checkpoint: enzym activates DNA replication

---S: Synthesis-- DNA replication

---G2: Cell doubles organelles

2. Mitosis

---Prophase: nuclear membrane disappears

---Pro Metaphase: spindle fiber

---Metaphase: Chromosomes line up in the middle of cell

---Anaphase: Apart

---Telophase: Two nuclei and partial cell membrane

3. Cytokinesis

Create two cells. Pinch cell membrane.

We also observed some cells at different stages:

For more detailed explanation on mitosis, I have more information in my blog from before.

Link to my Cell Tour Prezi:
http://prezi.com/z_cw0r42ucms/?utm_campaign=share&utm_medium=copy&rc=ex0share

Why do I not have two heads?! That could have been cool!!!

All organs of organisms can be traced back to one of the three layers of a developing embryo. These three layers are called germ layers.

All animals' structures derive from the germ layers. After cell divisions, the embryo looks like tubes within a tube. The very outside layer is called ectoderm. It develops into skin and nervous system. The middle layer develops into mesoderm. It develops into tissues in between guts and skin. For example, skeleton and muscles. The very inside layer, endoderm, develops into inner structure. For example, the inner organs. 

The small patch of tissue on a developing egg that directs other cells to form a full body is called an organizer. The organizer contains a gene called "Noggin," which contains information that directs the cells to form a body. 

If one injects extra noggin into an embryo, it will develop extra back structure or an extra head.

A Hox gene provides the head-to-tail organization of an embryo. The gene that controls the head is on one end and the gene for the tail is on the other end. As a result, the embryo can develop a head on one side and a tail on the other side.

Microscope

We observed things with microscopes last class.
A lovely photo of a flea:

Cells of a plant:

My cheek cells....

Organism in a drop of salt water... and an air bubble....:

For extra credit:

Since the mother dog has yellow pigment and had black and yellow pigment offsprings,

She might be Aa or aa. Since the ratio of the puppies' phenotype 1:1, the father dog should accordingly be aa or Aa.

BEHIND ON BLOG!!!!!!!!

I am really behind on my blog... Guess I'll just cramp a bunch of stuff into this ONE...

General Genetic Problems:
There are two ways. First is the Quick way:

Basically write out the possible combinations of the two traits and list the possibilities out in a huge square.

And then there's the Fitz's way:

Wowwww so much math!!! But I'm Asian so it's no big deal. Put the alleles that are in charge of the same traits in the same square and list all the possibilities out. And then calculate the ratios. Voila.

Genotype: The allele expression.

Phenotype: What the trait looks like.

Special Genetics:

Epistasis:

The different combinations of alleles creates different phenotypes. For example:

Incomplete Dominance:

Both alleles in heterozygous organism may be expressed in the phenotype. For example: Red rose x White rose = Pink rose.

Codominance:

Both alleles are expressed in phenotype. For example: Blood type.

Sex-Linked Genes:

Sex-linked genes that do not determine sex are usually on X chromosome. Y chromosome usually only determine sex (male). Female has XX and male has XY. Therefore, males are more likely to posses sex-linked traits.

Meiosis:

Meiosis is the making of sex cells. 

1. Cell starts off with 2n (two pairs of chromosomes)

2. Interphase: DNA replication --> 4n (four pairs of chromosomes)

3. Prophase I: Homologous chromosomes cross over to provide diversity. Homologous chromosomes --> chromosomes that control the same traits but contain different messages, one from dad and one from mom.

4. Metaphase I: Chromosomes line up in the middle of cell, big ones on top, small ones in the bottom.

5. Anaphase I: Spindle fibers split the chromosomes apart.

6. Telophase I: Forms two cells. Each cell contains 2n.

7. Metaphase II: Chromosomes in each cell line up in the middle.

8. Anaphase II: Spindle fibers split each cell into two cells.

9. Telophase II: Forms four sex cells that each contains 1n. The genes contained are randomly from mom or dad because of crossing over.

Mitosis:

MY BRAIN FREAKING BLEEDS BECAUSE OF THAT...

Diploids: 2n

Haploids: 1n

A useful video: http://www.youtube.com/watch?v=zGVBAHAsjJM

Pedigrees:

This is a pedigree. In order to identify a sex-linked trait: male offsprings have a greater chance in having sex-linked traits. In order to identify if a trait is dominant or recessive: refer to the ratio.

My PREZI on Huntington's Disease: http://prezi.com/xvcplbxsbqea/?utm_campaign=share&utm_medium=copy&rc=ex0share