1. Section 12-3 RNA & Protein Synthesis
Chapter 12 DNA & RNA
Section 12-3 RNA & Protein Synthesis

2. RNA Used For Protein Synthesis
Types of RNA
RNA Used For Protein Synthesis
Three Types of RNA
Messenger RNA, mRNA
Ribosomal RNA, rRNA
Transfer RNA, tRNA

3. Types of RNA mRNA rRNA tRNA
Template to construct protein. It brings the message from the DNA to the ribosome.
rRNA
Part of ribosome structure
tRNA
Transports amino acids from cytoplasm to the ribosomes

4. Transcription
The process of copying part of the DNA nucleotide sequence into a complementary sequence of RNA

5. Transcription
Requires the enzyme RNA Polymerase
Step 1. RNA polymerase binds to DNA and separates the DNA strands.
Step 2. RNA Polymerase uses one strand of DNA as a template to polymerize nucleotides into RNA

6. After Making mRNA Introns (active segments of nucleotides)
RNA Editing
After Making mRNA Introns
Are Snipped Out
Exons Remain,
(active segments of nucleotides)

7. The Genetic Code Proteins are long chains of amino acids.
There are 20 different amino acids
The order of amino acids in the protein determine its shape and function

8. There are 20 amino acids but only
The Genetic Code
There are 20 amino acids but only
4 bases in RNA
Adenine A
Cytosine C
Guanine G
Uracil U

9. The Genetic Code The genetic code consists of “words” three bases long
Each “word” is called a Codon:
three consecutive nucleotides that specifies a single amino acid

10. UCGCACGGU = RNA Sequence CAC codes for Histidine
The Genetic Code
For Example:
UCGCACGGU = RNA Sequence
UCG-CAC-GGU = Codons
UCG codes for Serine
CAC codes for Histidine
GGU codes for Glycine

11. Code Wheel

12. The Genetic Code 4 Bases Codons Defined with 3 Bases
There Are 64 Possible
3-base codons
Since there are only 20 amino acids, some amino acids are represented by multiple codons

13. Translation
Translation is the process of of decoding the mRNA into a polypeptide chain
Ribosomes
Read mRNA and construct the proteins

14. Translation Step 1
mRNA leaves the Nucleus

15. Translation Step 2 mRNA binds to the ribosome. tRNA attaches
Anticodons on the tRNA line up with codons on mRNA The other end of the tRNA is an amino acid

16. Translation Step 3
Ribosome connects the amino acids together as they come into the ribosome

17. Translation Step 4 A polypeptide (Chain of Amino Acids) is formed.
Polypeptide chain grows until the mRNA STOP Codon is reached

18. Blueprints of the Master Plan
The Roles of RNA & DNA
DNA =
Master Plan
RNA =
Blueprints of the Master Plan

19. Proteins At the end of translation a protein is formed.
Proteins are enzymes that catalyze and regulate chemical reactions
Proteins can also be structural.