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Honors Biology 2006-2007
The Structure of RNA
Honors Biology 2006-2007
Quick Review § What do we know about DNA structure? § What do we know about DNA function? § What do we know about DNA replication?
Honors Biology 2006-2007
What do we know? § DNA contains genetic information
“transforming” factor
§ Metabolic pathways are controlled by enzymes enzymes are proteins
§ How do we move information from �DNA to proteins?
Honors Biology 2006-2007
The “Central Dogma” § Flow of genetic information in a cell
How do we move information from DNA to proteins?
transcription translation
replication
protein RNA DNA trait
DNA gets all the glory,
but proteins do all the work!
Honors Biology 2006-2007
The Big Picture
Honors Biology 2006-2007
RNA is the Key! § Traits, like eye color, are
determined by proteins that are coded in DNA.
Our cells, however, need a “secret decoder ring” to express the code……….
AND, we need to get the instructions on how to make the protein from the nucleus and to the ribosomes.
ENTER: Ribonucleic Acid
(RNA)
Honors Biology 2006-2007
Protein Production § DNA molecules provide the
instructions for making proteins
§ BUT, RNA molecules are what build the proteins based on those instructions.
The workers for Protein Synthesis are RNA molecules.
Honors Biology 2006-2007
Honors Biology 2006-2007
RNA Structure § RNA structure differs from DNA
structure in 3 ways:
1. RNA is single stranded 2. RNA is composed of the sugar
Ribose 3. In RNA, a new base Uracil
replaces Thymine
Honors Biology 2006-2007
RNA Nitrogen Bases § Both RNA and DNA contain four nitrogen bases,
but instead of Thymine, RNA contains Uracil (U)
Uracil forms a base pair with Adenine, just as Thymine does in DNA.
§ RNA: U - A § DNA: T - A
Honors Biology 2006-2007
DNA vs. RNA Venn DNA RNA
Honors Biology 2006-2007
Types of RNA Molecules § 3 types of RNA molecules help to build proteins:
1. Messenger RNA (mRNA): “the messenger”
– Runs information from DNA in the nucleus to cytoplasm.
2. Ribosomal RNA (rRNA): “the builder”
– Clamps onto the mRNA and use its information to assemble the amino acids in the correct order.
3. Transfer RNA (tRNA): “the transporter”
– Transports amino acids to the ribosome to be assembled into protein.
Honors Biology 2006-2007
Where’s RNA?
Honors Biology 2006-2007