1. DNA & Protein Synthesis
               

2. Structure of DNA Double stranded helix
Structure determined in 1953 by Watson and Crick.
Composed of nucleotides.

3. Nucleotides Composed of sugar, phosphate, and nitrogen base
Sugar-Phosphate Backbone
Deoxyribose sugar
Phosphate group

4. Nucleotides continued ...
Nitrogen base
Adenine
Thymine
Cytosine
Guanine
Weak hydrogen bonds hold nitrogen bases together
Sequence of nucleotides determines genotype of organism. }
pair }
pair

5. DNA Replication
Enzyme breaks hydrogen bonds that hold the nucleotides together DNA unzips.
Free nucleotides pair with exposed nucleotides on both strands.

6. Animation

7. DNA Replication
T-A-C-A-C-G
Complementary strand?

8. From DNA to Protein ...

9. X X X X

10. Genes and Proteins RNA: helper DNA
DNA determines your: amino acid sequenceprotein production.
RNA: helper
DNA
Single strand Ribose sugar, not deoxyribose sugar.
Uracil (nitrogen base) replaces Thymine of DNA, bonding with Adenine

11. mRNA
3 Types of RNA “WORKERS”
Messenger RNA (mRNA): carries genetic info. from nucleus to cytoplasm
Ribosomal RNA (rRNA): attach to mRNA; assemble the amino acids in order.
Transfer RNA (tRNA): transfers amino acids to the ribosome to be assembled into protein.

12. Step 1: Transcription
DNA making a mRNA in the nucleus so genetic message can get to cytoplasm

13. Animation

14. Step 2: Translation: 1. Changes mRNA message to amino acids 2
Step 2: Translation: 1. Changes mRNA message to amino acids 2. Amino acids form a protein tRNA carrying an amino acid, binds to mRNA.

15. Translation

16. Translation

17. The Genetic Code Proteins determine ALL of your characteristics!!! U
Protein = Amino Acid + Amino Acid + Amino Acid + …
There are 20 amino acids = “gazillion” proteins.
Each set of 3 nitrogen bases forms a triplet,
called a codon on mRNA
called an anticodon on tRNA
Start and Stop:
AUG is the start codon.
UAA, UGA, UAG are the stop codons. U A G

18. Genetic Code

19. Animation

20. Genetic Changes ...

21. Mutation: A Change in DNA
Simple error
environmental
chemical or radiation
Can happen in all cells
                                            
Melanoma

22. Two types of gene mutations:
Point mutation
change in a single nitrogen base pair in DNA
Results in the change of one amino acid of a protein.
Frameshift mutation –
One nitrogen base is added or deleted
results in a drastic change in the
amino acid sequence.

23. Point & Frameshift Mutations

24. Types of Mutations

25. Chromosomal Mutations
Nondisjunction - organism has one more or one less chromosome than it should.
Piece of chromosome could break away and become lost, or it could rejoin upside down.

26. Causes of Mutations Mutagens - agent that causes change in DNA.
Radiation - x-rays, ultraviolet nuclear
Chemicals asbestos formaldehyde
tobacco

27. Repairing DNA
Often occurs naturally by the enzymes of the organism. However, if the exposure to the mutagen is very high, the chance for repair is slim.