1. Making Proteins

2. Proteins What is a protein? Long chain of amino acids hooked together
Only 20 amino acids exist, but they can be combined countless ways

3. Proteins & Genes
Genes have instructions for what amino acids link together and in what order they should be linked
1 gene has the directions for 1 protein
DNA molecules are just genes after genes after genes (directions for proteins, after proteins…

4. What determines the order of amino acids?
THE GENETIC CODE!
The genetic code consists of only 4 letters!
A, T, G and C
A and G are called purines
T and C are called pyrimidines
Purines always bond with pyrimidines A – T and G – C.

5. What determines the order of amino acids?
The order of nucleotides/nitrogen bases determines what amino acids are used to make a protein
Codon—set of three nitrogen bases in a row that code for an amino acid

6. How many codons are present? How many amino acids will be made?
T G A A C T G T T A T A
How many codons are present?
How many amino acids will be made? 4 4

7. Protein Synthesis
Has two parts
Transcription
Translation

8. Transcription Creating a copy of mRNA from DNA
DNA does not turn into mRNA
DNA must stay in the nucleus where it is protected and cannot be destroyed
mRNA will leave the nucleus, and go the ribosome where the protein will be made
The mRNA copy is COMPLEMENTARY not identical to DNA

10. Differences between DNA & RNA
Sugar
Phosphate
group
Nitrogen
bases
Strands
Deoxyribose
Ribose
Same
Same
A C G T
A C G U
Two
One

11. Practice transcription
G C T A T C A A T C G G
C G A U A G U U A G C C
T T A A T A C G T T C G G
A A U U A U G C A A G C C
C C A C G T G C A T
G G U G C A C G U A
A G C T T A G C C A T
U C G A A U C G G U A
DNA
mRNA

12. Translation
Actual protein construction, mRNA provides the instructions to join amino acids together
Transfer RNA (tRNA) with the help of ribosomal RNA (rRNA) reads the mRNA
Occurs at the ribosome
Anticodon—set of three nitrogen bases on tRNA that match a codon on mRNA

13. DNA TTT ACC TAC
mRNA AAA UGG AUG
lys
trp
met