1. Introduction to DNA
Structure

2. Vocabulary
DNA (Deoxyribonucleic Acid) – A nucleic acid that contains a deoxyribose sugar. Is a long molecule that is made up of units called nucleotides
Nucleotides – Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base. The THREE basic units of DNA

3. DNA
DNA contains the genetic code of an organism, with traits expressed through proteins made by cells
DNA can be found in the nucleus and mitochondria.

4. 2 rings
1 ring

5. Double Helix
DNA resembles a twisted ladder, with sugars and phosphates on sides, and nitrogen bases as rungs

6. 5’ has a free Phosphate
3’ end has a free Sugar

9. Nitrogen Bases
The nitrogen bases of DNA from complementary base pairs with adenine pairing with thymine, and cytosine pairing with guanine
The nitrogen bases spell out a coded message.

10. Quiz: DNA 4. What does a double helix look like?
5. What does DNA stand for?
Degraded Nucleic Acid
Deoxyribose Nitrogenous Acid
Deoxyribonucleic acid
6. What was Rosaline Franklin known for?
Finding out the structure of DNA
Taking pictures of DNA with a x-ray
Discovering the existence of DNA
7. What are Watson and Crick known for?
Name the three parts of a nucleotide.
Find the complimentary strand for the following DNA strand:
ATTTCGTGCAGA
??????????????
3. Do purines of pyrimidines have two rings?

11. Introductions to DNA
Replication

12. Replication
DNA replication happens in the Synthesis phase of the cell cycle
Happens BEFORE mitosis
Replication

13. DNA Replication
When DNA is replicated or copied, it results in two IDENTICAL strands.
Replication happens in three simple steps:
The two original strands of DNA are separated by helicase
DNA Polymerase adds complimentary nucleotides to each strand.
Two DNA molecules form that are identical to the original.

14. Step 1: DNA Separates
The DNA helix unwinds with the help of enzymes called DNA helicases.
Nucleotide bases separate at an area called the replication fork.

15. Step 2: DNA Polymerase adds nucleotides
New
Strands
forming
At the replication fork, DNA Polymerase move along each DNA strand and add complimentary nucleotides.
Adenine with thymine
Cytosine with Guanine
Two new strands begin to form.

16. Step 3: Two DNA Molecules form
DNA polymerase continues adding nucleotides until all the DNA has been copied.
DNA polymerase detaches and two new identical DNA molecules are left.

17. DNA Polymerases other role…
Because errors can occur in DNA replication, DNA polymerase also has a role in fixing the new DNA strands.
DNA polymerase fix mismatched nucleotides

18. DNA Replication in Eukaryotes
Eukaryotes have one long DNA strand for each chromosome
semi conservative model (new double helix has 1 parent strand + 1 new daughter strand)
replication fork
Parent strand
Daughter strand

19. DNA REPLICATION in Prokaryotes
Prokaryotes have one circular DNA
replication fork

20. PASTA DNA LAB Follow Procedure I to make a model of DNA.
Follow the directions EXACTLY the same EXCEPT instead of tying the noodles on string, GLUE THEM on to notebook paper.
In Procedure two, make a model of DNA “unzipping” or separating on another piece of paper.
The show 2 identical DNA strands that were made.
They should look EXACTLY like the first DNA strand.

21. Pasta DNA
Wheels- Sugar
Noodle-Phosphate
Paper clip- Bases

22. From DNA to Protein
Transcription

23. Transcription & Translation
Making Proteins…
…involves a series of steps.
Transcription & Translation
mRNA is made in transcription.
Protein is made in translation.

24. RNA RNA differs from DNA in three ways: Single stranded
Has uracil instead of thymine nitrogen bases
Contains ribose sugar instead of deoxyribose in its backbone.

25. Transcription in 3 easy steps Step 1
Transcription starts when RNA polymerase binds to a specific DNA sequence that tells cell to START transcription.
Remember, A,T,C, and G “spell” out messages.
START

26. Next, the RNA polymerase unwinds and separates the DNA.
Step 2
Next, the RNA polymerase unwinds and separates the DNA.

27. Step 3
Last, RNA polymerase adds complimentary RNA nucleotides to the DNA strand.
The polymerase adds:
cytosine to guanine and guanine to cytosine
adenine to thymine BUT uracil to adenine.

28. Why make Messenger RNA? Messenger RNA
When a cell needs a protein, mRNA is created.
mRNA carries instructions for building a protein and delivers it out side of the nucleus.
Messenger RNA

29. ACTIVITY! ^_^
Your objective is to take the following DNA strands and transcribe them into RNA.
Materials: Pipe cleaners and colored beads.
Green: Adenine; Yellow: Guanine; Red: Thymine; Blue: Cytosine; White: Uracil.
Procedure: Transcribe the SECOND STRAND of each of the following DNA sequences.
Make your DNA and RNA using the pipe cleaner given and the colored beads.
Show me your RNA strand. If it is correct then turn into me your RNA sequences written down on paper. Return the beads and pipe cleaners
DNA sequence one
Strand one: ATGCTGAAG
Strand two: TACGACTTC
DNA sequence three
Strand one: TATCGTAGT
Strand two: ATAGCATCA
DNA sequence two
Strand one: CGCTTAAAC
Strand two: GCGAATTTG
DNA sequence four
Strand one: ATGCAATAG
Strand two: TACGTTATC

30. From DNA to Protein
Translation

31. Vocabulary Amino acids: make PROTEINS
Ribosomal RNA are part of the structure of ribosomes.
They hold the mRNA and two tRNAs in place during translation
tRNA molecules are single strands of RNA that carry a specific amino acid with them.
Amino acids: make PROTEINS

32. Vocabulary Codons: instructions written as three nucleotide sequences.
Each codon corresponds to an amino acid or start or stop signal.
Ex:
GUA  Valine
UUC Phenylalanine

33. To build a protein…
…we must move on to our next step that moves our RNA out of the nucleus and into the cytoplasm.

34. Translation
mRNA moves into the cytoplasm where it binds with a rRNA, and a tRNA carrying an amino acid.
The codon is ready to receive the next tRNA and its amino acid

35. Peptide
bond
Once mRNA is holding two tRNAs, each carrying specific amino acids, enzymes form peptide bonds between the two amino acids.
The tRNA in the first site prepares to detach, leaving behind the amino acid.

36. Another tRNA fills in the empty site.
This process repeats until a STOP codon is reached (UAG, UAA, or UGA).
The amino acid chain is release, forming into a new protein.

37. Amino acids form protein.
Transcription
Amino acids form protein.