1. RNA & Protein Synthesis

2. What does RNA stand for? Ribonucleic Acid Location
Structure of RNA
What does RNA stand for?
Ribonucleic Acid
Location
Nucleus and Cytoplasm

3. Characteristics of RNA
Single Stranded
Building Blocks = Nucleotides
Ribose Sugar
Phosphate Group
Nitrogen Bases
Base Pairing Rules
Adenine = Uracil
Cytosine = Guanine
Adenine
Uracil
Cytosine
Guanine

4. Types of RNA and their Function
mRNA (messenger RNA)
Carries a copy of the instructions for assembling amino acids into proteins
tRNA (transfer RNA)
translates the code from mRNA and transfers amino acids to the ribosome to build proteins
rRNA (ribosomal RNA)
make up the two subunits of ribosomes (used to make ribosomes)

5. HOW ARE PROTEINS SYNTHESIZED?
Protein carried on RBC

6. Proteins: complex molecules made of amino acids
Functions of proteins
Enzyme (catalyze reactions/processes)
Control cellular transport
Cellular communication

7. The Central Dogma How are Proteins made? States…..
Information flows in one direction = DNA to RNA to Protein
One gene on a strand of DNA codes for one protein

8. The Central Dogma requires Two Steps for Protein Synthesis
Transcription
Translation

9. Step 1: Transcription Occurs in the nucleus
Messenger RNA (mRNA) copies a gene from DNA
RNA Polymerase adds nucleotides to their complementary base pair to the gene (section of DNA)
DNA unzipped
mRNA nucleotides
Enzyme that causes transcription to occur

10. Practice Transcription
If the gene on DNA is…
TAC-GCA-CCG-AAT
Then what will the Transcribed mRNA be?
Remember the rules of complementary base pairing
Remember mRNA has Uracil instead of thymine
Set of three DNA nucleotides is called a triplet
DNA code = TAC-GCA-CCG-AAT
mRNA code = AUG-CGU-GGC-UUA
Set of three mRNA nucleotides is called a codon

11. Transcription: DNA to mRNA
mRNA must copy the order of nucleotides without error
The order of the nucleotides is the genetic code for building the protein
If the order is incorrect the protein will not function
DNA
mRNA
RNA polymerase bonds the mRNA nucleotides together moves along the DNA

12. Transcription When Transcription ends:
mRNA leaves the nucleus and travels to a ribosome for Step 2 (translation)
mRNA

13. Step 2: Translation Occurs in the Ribosome
tRNA translates the mRNA message into a protein
protein

14. A set of three nucleotides in tRNA is called an anticodon
Anticodon = set of three nucleotides on tRNA
There are many different tRNA molecules
Each tRNA
contains a specific anticodon
carries a specific amino acid

15. How does Translation happen?
tRNA brings amino acids to the ribosome where proteins are made.
The anticodon on tRNA pairs with the complementary codon on mRNA
The amino acids is then added to the forming protein.
Translation begins only at the start codon AUG and ends with one of three stop codons
The start codon is a sequence of nucleotides in the mRNA!!!!!

16. Translation: tRNA anticodons bond to the mRNA codon
The amino acid that tRNA is carrying bonds to the other amino acids in the forming protein.

17. Translation results in a polypeptide (protein)
The amino acids form a polypeptide chain or protein molecule when the entire message is completely translated.

18. Practice Translation What are the complementary anticodons?
If the mRNA code is: AUG-CGU-GGC-UUA
What are the complementary anticodons?
mRNA = AUG-CGU-GGC-UUA
tRNA = UAC-GCA-CCG-AAU
Finally each tRNA carried a specific amino acid which linked to the one before to build the protein!

19. Codon Table
Use the mRNA strand to determine which amino acid is being added to the protein.
First nucleotide in the codon correlates to the innermost circle
Second nucleotide in the codon correlates to the second ring
The third codon correlates to the outermost ring.
This tells you what amino each codon corresponds for.
mRNA = AUG-CGU-GGC-UUA

20. Mutation Mutation – Any change in the genetic code.
Any change in the order of nucleotides can result in changes to the amino acid order.
Thus changing the protein.
STRUCTURE=FUNCTION
Regardless of the organism, codons code for the same amino acid.