Tuesday, November 23, 2010

DNA Fingerprinting


1. DNA is unique for everyone. The only exception is if a person has what?
If a person has an identical twin, then the DNA is not as unique for that specific pair.

2. What are DNA fingerprints used for?
DNA fingerprints can be used for determining a biological mother or father, identifying the suspect of a crime, and it can be used to clear someone's name.

Part 1 “It Takes a Lickin”

3. What “crime” was committed?
Someone licked his lollipop.

4. What bodily fluid was removed from the “crime scene” to get DNA?

Part 2 “DNA Fingerprinting at the NOVA Lab”

5. What does a restriction enzyme do?
They cut the long DNA molecules depending on the code within the DNA molecule.

6. What is agarose gel?
Agarose gel acts like a molecular strainer, allowing the smaller pieces to move through easier, rather than the larger pieces of DNA.

7. What is electrophoresis?
Electrophoresis is the process of moving molecules with an electric current.

8. Smaller fragments of DNA move _____more easily____than longer strands.

9. Why do you need to place a nylon membrane over the gel?
You need to place the nylon on the membrane because it acts like a sheet of paper and picks up the DNA.

10. Probes attach themselves to ___the DNA fragments__ .

11. Which chemical in your “virtual lab” is radioactive?
The probes are radioactive.

12. Sketch your DNA fingerprint.

13. Based on your DNA fingerprint, who licked the lollipop?

Honey licked the lollipop.

Click on the Link “DNA Workshop” (if this link won't load, scroll down to the bottom where it says "try the non-java script version)
Once you’re there, go to the link “DNA Workshop Activity” and practice with DNA replication and protein synthesis.

Browse the DNA Workshop site.

14. What kinds of things could you do at the DNA workshop?
At the workshop, you can do an activity of DNA synthesis or replication, read related articles (such as Francis and Crick), and learn about key words in the glossary.

Find an Article about DNA

Go to http://www.thegenesite.com/

15. Read an article about genetics at this site that you might find interesting, or use the "Search" box in the upper right hand corner to search for DNA fingerprinting.

Title of Article __How does DNA Fingerprinting Work?__ Author and Date ____Dalya Rosner 2000- 2010____

Summarize what the article was about. Write this in a paragraph format.

DNA fingerprinting is a term that has been rumored about in the popular media for many years, due to its power to reprimand and save. It grew from it's highly doubted position in science and religion to a widely categorized branch of knowledge. To sum it up, it's a technique for determining the likelihood of genetic material's related origin. While researching (Dayla Rosner is a PhD student at Cambridge University) she discovered that 99% of human DNA has approximately 100% similarities between individuals, whereas the 1% that differs enables scientists to distinguish identity. However, there is a massive amount of "junk" that does not get coded into useful proteins, therefore preventing it from doing its proper job. This is what forensic scientists search for in investigations. It usually occurs with every 200 characters, so chemists have a good idea of where the damaged gene is located. They crop the DNA and formulate bands which help distinguish the difference, similarities, and where it derived. Obviously, the more similar the band is, the better chance that it is identical. This science has evolved o much in the past ten years, so much, in fact, that it can aid us in predicting the future good-will of ours and generations to come. This leads to screening parents and embryos and understanding gene functions, not only the disease that comes along with them.

Wednesday, November 3, 2010


Mitosis Tutorial
#1 Which stage does the following occur?

Chromatin condenses into chromosomes: Prophase
Chromosomes align in center of cell: Prometaphase
Longest part of the cell cycle: Interphase
Nuclear envelope breaks down: Prometaphase
Cell is cleaved into two new daughter cells: Prometaphase
Daughter chromosomes arrive at the poles: Telophase

#2 The colored chromosomes represent chromatids. There are two of each color because one is an exact duplicate of the other.

How many chromosomes are visible at the beginning of mitosis?
There are 4 visible chromosomes at the beginning.

How many are in each daughter cell at the end of mitosis?
There are 8 daughter cells at the end of mitosis.

The little green T shaped things on the cell are:
The light green T shaped things on the cell are centrioles.

What happens to the centrioles during mitosis?
The centrioles moves around along with the movement of the chromosome, and eventually is separated from it's pair in the mother cell when developing the daughter cells.

#3 Identify the stages of these cells:
1) Metaphase
2) Cytokinesis
3) Prophase

Another Mitosis Animation
Prophase: The centrioles move to opposite sides of the cell, while the chromatin in the nucleus condenses and its membrane dissolves, and the chromosomes connect to their "sister" chromosome.
Metaphase: The sister chromosomes divide and attach to spindle fibers that exrtract them, while the chromosomes gravitate towards their corresponding poles (centrioles).
Telophase: The chromosomes pull at their opposite poles, splitting the cell in half to produce two daughter cells and making new membranes. The chromosomes return to their original, undetected, stringy state.

Onion Root Tip
# of cells:
Interphase: 20-57.142%
Prophase: 10-28.571%
Metaphase: 3-8.571%
Anaphase: 2-5.5%
Telophase: 1-2.7%
Total: 36-100%

Mitosis in Whitefish & Onion Root
View 1: Telophase
View 2: Metaphase
View 3: Prophase
View 4: Anaphase

View 1: Anaphase
View 2: Metaphase
View 3: Prophase
View 4: Telophase
View 5: Anaphase