Tuesday, November 23, 2010

DNA Fingerprinting Lab

1. DNA is unique for everyone. The only exception is if a person has what?
1A. If a person has an identical twin then their DNA is not unique.

2. What are DNA fingerprints used for?
2A. DNA fingerprints are used for many things such as identifying a biological parent, or as evidence in a crime.

Part 1 “It Takes a Lickin”
3. What “crime” was committed?
3A. Jimmy's property had been damaged (his lollipop was eaten).

4. What bodily fluid was removed from the “crime scene” to get DNA?
4A. To eat a lollipop you have to lick which means a trace of the criminal's saliva was left. The saliva is what will be used to create a DNA fingerprint.

Part 2 “DNA Fingerprinting at the NOVA Lab”

5. What does a restriction enzyme do?
5A. A restriction enzyme chops the DNA at different places like a pair of scissors. The location in which the enzyme cuts depends on how the molecule/gene is coded. A certain sequence can make a certain enzyme cut at a certain spot.

6. What is agarose gel?

6A. Agarose is a thick gelatin-like matter that strains molecules, letting smaller DNA particles percolate better than larger ones.

7. What is electrophoresis?

7A. Electrophoresis is the process in which molecules move along an electric current. Since opposite poles attract, the negative DNA bits ar

e pulled towards the positive end of the tray.

8. Smaller fragments of DNA move
easier than longer strands.

9. Why do you need to place a nylon membrane over the gel?
9A. You need to place a nylon membrane over gel so you can pick it up easily. It is pretty difficult to pick up the gel by itself, but the nylon membrane, a paper-like substance, will suck up the DNA.
10. Probes attach themselves to DNA fragments (on nylon membrane).

11. Which chemical in your “virtual lab” is radioactive?
11A. The chemical(s) in the lab that are radioactive are the probes.

12. Sketch your DNA fingerprint.

13. Based on your DNA fingerprint, who licked the lollipop?
13A. The culprit was Honey Sweet.

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?

14A. I was able to go through the process of replicating DNA and synthesizing protein in which I matched up base pairs, transcribe DNA, match anticodons,

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

DNA Tests Show African Elephants Are Two Species

By Hillary Mayell/August 24, 2001

In the past, elephants have been split into two species: Asian and African. Now, according to a DNA fingerprinting test, the African forest and savanna elephants are two completely different species. Almost as diversified as a lion and tiger. Unfortunately, if this information is correct, then elephants are in even more danger than we previously thought. This theory is based on Different Characteristics and Major Implications. Physically the savanna and forest elephants vary by their overall body, tusk, ear, and skull shape. Socially they differ as well, savanna elephants travel in much larger units than forest elephants. Of course, scientists have been educated on these trait differences for a while. It was found that these variations were not strong enough to back up the theory. That is where DNA comes in, previously these DNA tests were not very accessible, but are now. It is essential that this theory is accepted because it can help specify how to better save the elephants. More specific strategies can now be put into place. For example: logging imposes a major threat to forest elephants, whereas expansion of agriculture is lethal to savanna elephants.

Wednesday, November 3, 2010


1. Which stage does the following occur

Chromatin condenses into chromosomesProphase, The first mitotic stage in which the copied DNA and protein condense to grow mitotic spindle.
Chromosomes align in center of cell.Metaphase, pressure is put on the spindle fibers which causes the chromosomes to align.
Longest part of the cell cycle.Interphase, the DNA duplicates, the centrioles split, and proteins produce. Can last 12-24 hours.
Nuclear envelope breaks down.Prometaphase, the nucleus is not visible anymore, spindle fibers go on top of each other in the cell center.
Cell is cleaved into two new daughter cells.Cytokinesis, spindle fibers start degrading until only a small part is left. It is in this part that a ring is created and eventually cleaves the cell into two daughter cells.
Daughter chromosomes arrive at the poles.Telophase

Watch the video carefully.

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? At the very beginning none, but towards the middle four.

-- How many are in each daughter cell at the end of mitosis? In the very end there are none, but in Cytokinesis there are three.

--The little green T shaped things on the cell are: Centrioles.

-- What happens to the centrioles during mitosis? They divide.

3 . Identify the stages of these cells:

This is metaphase because the chromosomes are all aligned.This stage is Cytokinesis because the daughter cells are being cleaved.This stage is Prophase because the mitotic spindles are forming.

Another Mitosis Animation

Go to www.johnkyrk.com/mitosis.html

View the animation and sketch the cell in:


The chromosomes are condensing to form long mitotic spindles.


The spindle fibers are pressurized which causes the chromosomes to align in the center of the cell.


The chromosomes and spindle fibers are being pulled apart to opposite ends of the cell by protein. The chromosomes are being stretched out and turning very long and thin. Finally two nuclear envelopes envelope the stretched out chromosomes and the cell splits into two daughter cells.

Onion Root Tip - Online Activity


Read the introduction, then click the “next” button.

You will have 36 cells to classify. When you’re finished, record your data in the chart below.


Number of cells


Percent of cells

(calculate: number of cells divided by total cells x 100 )

55%27%8.3%5%2.7%100 %

Mitosis in Whitefish & Onion Roots


For each organism, identify the stage of mitosis.

View 1
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