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