1. The Central Dogma
Through the production of mRNA (transcription), and the synthesis of proteins (translation), the information contained in DNA is expressed.

2. DNA and Protein Synthesis
DNA contains the genetic information to
make amino acids
Amino acids combine to make proteins
These proteins determine the physical traits
of an organism and control cellular functions.
Proteins do everything,
and DNA gets all the
credit!
Think of them as tiny minions
who do all the work

3. DNA and Protein Synthesis

4. DNA and Protein Synthesis
Codon: three bases code for a specific protein:
ex: AAA = Lysine
The codons code for 20 amino acids
Just like the alphabet has 26 letters to make all
the words we know, the 20 amino acids make
all the different proteins found in living
organisms
The codons are the template for protein synthesis,
which takes place on the ribosomes in the
cytoplasm.

5. Name the Amino Acid: UAU CCG AGU Tyrosine GCA Proline Serine Alanine
DNA and Protein Synthesis – Codons and amino acids
Name the Amino Acid:
UAU
CCG
AGU
GCA
Tyrosine
Proline
Serine
Alanine

6. But… How does the information get from the DNA to the cytoplasm?
DNA and Protein Synthesis
But… How does the information get from the DNA to the cytoplasm?
mRNA

7. DNA and Protein Synthesis - Transcription
1) DNA unzips
2) mRNA (messenger ribonucleic acid) copies info from DNA using base pairings
RNA is different from DNA
Single stranded, not double stranded
Instead of deoxyribose, it has ribose
instead of Thymine, it uses Uracil
3) Carries the genetic code from the nucleus to the
ribosome in the cytoplasm

8. DNA and Protein Synthesis - Translation
Ribosome attaches to mRNA and starts reading the codons
tRNA (transfer RNA) – carries amino acids and attaches them to the growing protein chain
When protein production is complete, the ribosome releases the protein chain

9. DNA and Protein Synthesis - Summary

10. DNA G A T T A C A C U A A U G U mRNA
DNA and Protein Synthesis
Practice making mRNA using the DNA template
DNA
G A T T A C A
C U A A U G U
mRNA

11. mRNA CUA AUG UGC DNA and Protein Synthesis
Amino acids are linked together in the same
order as the codons, creating a protein chain
Just like linking letters to make words, linking
amino acids makes proteins
mRNA
CUA AUG UGC
Leucine methionine
Amino Acid
Amino Acid
Amino Acid

12. Mutations are any changes that take place in DNA:
DNA and Mutations
Mutations are any changes that take place in DNA:
Can be spontaneous or caused by mutagens
ex: Chemicals, high temperatures, UV light,
radiation
Can change the genetic code, and be replicated
when forming new body cells.
In sex cells, can be passed on to offspring.
Mutations can be neutral, beneficial, or harmful
ex: Blue eyes – a mutation that occurred 6-10,000 years ago, can be traced back to one ancestor
what kind of mutation is that?

13. DNA and Mutations – Lets looks at different mutations
THE DOG BIT THE CAT

14. Substitution - Replace just one letter: THE DOG BIT THE CAR
DNA and Mutations - Substitution
THE DOG BIT THE CAT
Substitution - Replace just one letter:
THE DOG BIT THE CAR
Example: The sickle cell mutation. One amino acid out of a total 287 differs in sickle cell hemoglobin compared with normal hemoglobin.

15. Deletion: Delete just one letter (T): THE DOG BIT HEC AT
DNA and Mutations - Deletion
THE DOG BIT THE CAT
Deletion: Delete just one letter (T):
THE DOG BIT HEC AT
Example: Deletions of one or more base pairs have been associated with certain bowel cancers and with the most common form of cystic fibrosis, a disease characterized by unusually viscous mucus that impedes normal respiratory and digestive function.

16. Insertion - Add just one letter (E): THE DOE GBI TTH ECA T
DNA and Mutations-Insertions
THE DOG BIT THE CAT
Insertion - Add just one letter (E):
THE DOE GBI TTH ECA T
Example: Crohn’s disease is caused by an insertion of a Cytosine at position This leads to a premature stop codon, shortening the protein that is supposed to be transcribed.
Cells have “proof reading” proteins that constantly check the DNA and fix errors, so most are corrected.

17. Protein Synthesis- you try it!

18. DNA transcription and translation- you try it!