Unit+3

__Unit 3: Cell Division__
Notes: Mitosis - [|Meiosis Notes.mht] - Disorders


 * Assignments:** Onion Root Mitosis Online

**__Big Ideas__**
Scribe key points from Lesson.

Anna Pettersen 3/12:
 * Why do cells divide?**
 * To keep the Surface Area to Volume Ratio high
 * Cells remain small
 * Nutrients and other materials need to get into the cell, and waste need to get out to keep the organism alive
 * To replace dead cells
 * To grow and develop
 * Reproduction
 * To repair damage


 * DNA Packaging**
 * Chromatin is the form of DNA during interphase
 * Chromosome: Tightly wound DNA and protein structures



Elizabeth Goslin 4/18:

**Meiosis Big Ideas**
Meiosis:

Where? In the ovaries and testis.

Amount of DNA (conserved): Diploid - Haploid (2N - N)

There are two division stages in meiosis:

Meiosis I: - reproduction step (amount of genetic information is reduced by half). reduction division: 2N - N - there are two pairs of chromosomes (two long chromosomes and two short chromosomes, maternal/paternal) - reduction occurs: cells that have two pairs go to cells with one pair. - fate of the chromosomes is determined - Independent Assortment (leads to genetic diversity) - there is an equal chance for each possible path (think flipping a coin) - synapsis (the fusion of chromosome pairs) occurs (diversity)

Meiosis II: - similar to mitosis - no replication - separation of sister chromatids

I was reading Reader's Digest the other day and I happened to stumble upon on an article regarding stem cells. The article said that in November 2008 James Thomson from the University of Wisconsin and his research team created cells with the same chameleon like characterstics as embryonic stem cells but derived from human skin. This was achieved simultaneously by Japanese researchers too. Basically this newly induced pluripotent stem (iPS) cells were created by identifying four genes that could reprogram the DNA. These cells could transform themselves into different types of human tissue. For example just 12 days after mixing a sample of iPS cells with cocktail of proteins in a petri dish, newly formed cardiac cells started beating like a human heart. The ultimate goal here is to use the cells to heal diseased and damaged organs. (Lily Mu)

I found this article on Cancer. It's called 'Universal Cancer Cure?" Emmanuel Skordalakes from UPENN was able to decode part of the structure of telomerase and translate it into a 3-D image. By understanding what this enzyme look like scientists can then find another molecule that can turn off its damaging effects. 1211285280

media type="delicious" key="jplaman/bio2+unit3" ARG0="extended;title=Cell%20Division%20Links;bullet=%E2%80%A2;icon;showadd" width="150" height="200"