1. RNA (Ch 13.1)

2. The Role of RNA General Basics
Now that we know what DNA is, the question still remained as to how it worked?
RNA
RiboNucleic Acid  uses ribose sugar instead of deoxyribose
Consists of ONE long chain of nucleotides
General Basics
DNA consists of how the protein should be built  DNA needs to be copied to RNA  RNA contains the code for the proteins

3. RNA vs. DNA DNA RNA Main Components
deoxyribose, phosphates, nitrogenous bases
ribose, phosphates, nitrogenous bases
Number of Strands
Double helix (2 strands)
Single stranded
Nitrogenous bases
Adenine, cytosine, guanine, thymine
Adenine, cytosine, guanine, uracil
Task
Master plan
Blueprints
DNA is housed safely in the nucleus. If you took your master plan out of the “safe zone” and something happened to it, could remember every fact or detail to put it back together the exact same way?
RNA provides a blueprint or a copied version of the master copy. This allows for the instructions to leave the “safe zone.” If it is damaged or destroyed, the plans can be recopied.

4. DNA vs. RNA

5. Functions of RNA One job: Protein Synthesis
RNA controls the production of proteins, which are made of amino acids
Amino Acids: the building blocks of protein (20 amino acids)
Three Types of RNA
Messenger RNA (mRNA): carrying the copies (blueprints) of DNA to other parts of the cell
Ribosomal RNA (rRNA): proteins are assembled on ribosomes – small organelles composed of TWO subunits
Transfer RNA (tRNA): transfers the amino acids to the ribosomes as specific by the coded message

6. Types of RNA

7. RNA Synthesis Eukaryotic vs. Prokaryotic DNA DNA  RNA  Protein
Transcription
Translation
Transcription: segments of DNA serve as templates to produce complementary RNA molecules
transcribing DNA code into RNA to travel in the cell
most of the work occurs here
Eukaryotic vs. Prokaryotic DNA
Eukaryotic = nucleus
Prokaryotic = cytoplasm
RNA Polymerase
Binds to DNA and separates DNA strands
Assembles nucleotides into a complementary strand of RNA
This makes it possible for a single gene to make hundreds of RNA molecules

8. RNA Synthesis

9. RNA Synthesis (cont.)
Promoters: regions of DNA that have specific base sequences
These allow for RNA polymerase to know where to bind to make the complementary RNA strand
Similar signals tell when to stop transcription after the RNA strand is made
RNA Editing
Review the mRNA molecule before it is ready to be read
Introns: pieces that are cut out and discarded
Exons: remaining pieces that are spliced back together