1. The Wonderful World of DNA
(Deoxyribonucleic Acid)

2. Review Everything is made of matter Matter is made of molecules
Molecules are made from elements
DNA is a molecule that is made from other molecules

3. What does it look like

4. DNA Fun Facts DNA was first isolated in 1869 by Friedrich Miescher.
James Watson and Francis Crick figured out the structure of DNA in Although they did “borrow” much of the research to figure it out.
DNA is a double helix.
One chromosome can have as little as 50 million base pairs or as much as 250 million base pairs.
If unwound and tied together, the strands of DNA in one cell would stretch almost six feet but would be only 50 trillionths of an inch wide.
Over 99% of our DNA sequence is the same as other humans’

5. DNA is important because
It has a really long, scientific name
It is the instructions that code for the creation and maintenance of living things
It is what mitosis uses for its phases
All of the above makes DNA important 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

6. A double helix is like a Spiral Staircase A twisted ladder
A piece of licorice
More than one of the above are correct 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

7. The DNA model It all starts with the “backbone”
A Phosphate is connected to the deoxyribose sugar
The bonds holding them together are STRONG.
We don’t want the DNA to separate along backbone

8. The DNA model The building block is a nucleotide
DNA is built from small similar parts called nucleotides
It consists of three parts:
A phosphate
Connected to the Sugar
A nitrogen base connected to the sugar
There are 4 nitrogen bases: Adenine, Thymine, Guanine and Cytosine
They pair up on opposite sides of the DNA
Adenine with Thymine & Cytosine with Guanine

9. DNA has two backbones. True False 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1516 17 18 19 20 21 22 23 24 25 26 27 28 29

10. Nitrogen bases in DNA pair up like this:
A – C, G - T
G – A, T - G
A – T, G - C
They don’t pair up at all 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

11. A nucleotide is like A lego A brick A puzzle piece All of the above 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

12. A little video clip showing this DNA Stuff

13. The Code The A, T, G & C’s are set in an order for a specific trait
The code can only be read when the DNA is open
It is coded in 3 letter sequences.
Each 3 letter sequence is called a CODON.

14. Which would be an example of a codon?
CBA
GATTACA
KFAN
None of the above 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

15. Reading the Code When DNA is read, it is read one gene at a time
Each gene codes for a specific trait
When a gene is ready to be read, DNA unzips
A molecule called mRNA is formed as a copy of the code

16. mRNA mRNA (messenger RNA)
Made with Ribose sugar instead of Deoxyribose
Only a single strand, but still twisted
Uses Uracil as a nitrogen base instead of Thymine
Built as a match to DNA

17. Reading the code Each codon is represented by one AMINO ACID.
Amino Acids are assembled in the order of the code.
When assembled they are called PROTEINS.

18. We still haven’t said how the code is read!?
The actual reading is done by the RIBOSOMES outside of the nucleus.
They call for molecules call tRNA that carry specific amino acids
The tRNA’s bring in the aminos and attach them to the ones that are there, creating a long line of amino acids call a PROTEIN.

19. tRNA tRNA (transfer RNA) Is a short strand of RNA
Only 3 nucleotides long (1 codon)
Carry one specific amino acid that is specific to the code that it has

20. The Process is in Two Stages
Stage 1 (Transcription)
DNA unzips
mRNA is made
mRNA is released into nucleus
DNA zips back up

21. What is created in the end of transcription?
2nd half of DNA
tRNA
Unzipped DNA
mRNA
None of the above

22. Transcription Video

23. Stage 2 (Translation) mRNA goes out of the nucleus
Attaches to a ribosome at one codon
Ribosomes read the code and call for one of the tRNAs with the opposite code
tRNA matches up with the mRNA at the ribosome, attaches its amino acid to the others that are there (peptide bond between aminos), then leaves
Continues to do this until the mRNA runs out
mRNA returns to the nucleus and breaks up into its nucleotides.
The amino acid chain is the PROTEIN (or a polypeptide) and is released to control the trait

24. What is created in the end of translation?
Protein
tRNA
Unzipped DNA
mRNA
None of the above

25. Translation Video

26. Amino Acid Table