DNA : The Genetic Code
What is the “genetic code”?
• A set of instructions that tells the cell how to
build all of the components that make you!
Disputes
• DNA vs protein as the genetic code…
DNA Structure
Nucleotide
Protein Structure
Protein Structure:
Polymer of Amino Acids
Series of experiments pointed to the
same thing = DNA is the genetic
material
Series of findings led to the discovery
of the structure of DNA
DNA
• Contains the instructions for making
PROTEINS that determine your appearance.
• The order of the DNA BASES determines the
sequences of AMINO ACIDS in the protein.
Where is DNA found?
Where are proteins made?
DNA can’t leave the nucleus.
• So how do the instructions get where they
need to be?
http://www.youtube.com/watch?v=PEDQoQuIhkg
A MESSENGER!
DNA  RNA  Protein
DNA  RNA :: TRANSCRIPTION
RNA  Protein :: TRANSLATION
Transcription
• Keeping it in the same “language”
• Just different…a shortened version
RNA
• Ribonucleic Acid
• Another type of nucleic acid
• A polymer of nucleotides
– There are differences…
ACTIVITY…
Differences
•
•
•
•
•
Built with ribose rather than deoxyribose
Does not have thymine – uses uracil instead
Single stranded
Found in nucleus and cytoplasm
Comes in three types:
– mRNA (messenger)
– tRNA (transfer)
– rRNA (ribosomal)
RNA base pairing rules…
Steps of Transcription…
• Unwind DNA: HELICASE
• Only one strand is used: the CODING STRAND
To build the mRNA
Start adding nucleotides: RNA POLYMERASE