30th September 2010

Making our own DNA

Today, we went in depth into DNA. We went through that DNA uses a code to form different types of proteins to make different tissues or organs. The DNA code is the same as words as both make use of letters and when one letter is changed, the whole meaning is different. But this DNA code has a special name called condons. Codons are instructions to make different types of proteins. Alot of codons add up to form DNA. Codons makes use of 4 different letters(A, T, C, G)and only has a combination of 3 letters. The letters A, T, C and G have a special name known as Nitrogenou Bases. A stands for adenine, T stands for thymine, C stands for cytosine and G stands for guanine. For example, a single strand DNA may be like:

TAG CCG CGT TAG ACG TGA

DNA comes in a pair but the other half is complimentary of the original one. So A will always go with T and G will always go with C. So the complimentary strand of the single strand DNA above is like that:

ATC GGC GCA ATC TGC ACT

The double stranded DNA will twist into something like a spiral staircase withn a hollow interior. This is called DNA double helix.

After going through the topic, we were tasked to make a DNA model using stickers and 2 wires. We were given a total of 20 stickers. And on 5 stickers per letter(A, T, C, G), we were required to write a letter on both ends of the sticker. Then we pasted the stickers on the wires following the rule: A goes with T and G goes with C. And this is how my DNA looks like.

29th September 2010

Viewing DNA of a fruit

The lesson before this one, Mdm Riza told each of us to bring a either a banana or a strawberry as we needed to conduct a practical which was extracting DNA. On that day itself, although Mdm Riza emphasized to only bring bananas or strawberries, Alot of us bought different variety of fruits. These included apples, guavas, watermelons and others. Before conducting the practical, we were introduced to the topic DNA. We also got to listen to the DNA song.

Here are some things we went through:

- What does DNA stand for?

DNA stands for Deoxyribonucleic acid

-What is the function of DNA?

It contains genetic materials that are used to make protein

Where is DNA found?

Inside the nucleus of every cell.

- What are proteins for?

To make different organs and tissues.

Here are the steps for viewing the DNA of the fruit:

1) Use about 1/4 of the fruit.

2) Place the fruit inside a ziplock bag.

3) Mash it up until there are no big pieces left. (to break down the cell membrane)

4) Add in 1/2 a teaspoon of salt and 2 teaspoon of detergent. (to break down the nucleus wall)

5) Continue mashing it.

6) Let it settle for a while.

7) Pour a bit of it into a cylinder. Make sure no big pieces flow out.

8) Tilt the cylinder to 45 degrees and slowly pour in 10ml of alcohol.

This is how my DNA looks like: