Transcription and Translation:
What does a cell (or organism) do with its
genes??
The Structure of a DNA Molecule:
DNA, Genes, and DNA, Genes, and ChromosomesChromosomes
What Does a Gene Do?What Does a Gene Do?
Getting From a Gene to a Protein Occurs in 2 Steps:
1.TRANSCRIPTION:
transcribing DNA into RNA
2. TRANSLATION:
translating RNA into an amino acid sequence (protein)
So What Is RNA?So What Is RNA?
TranscriptTranscription & ion &
TranslatioTranslation n
OverviewOverview
TranscriptionTranscription
Now Now What?What?
We need a decoder We need a decoder ring!ring!
In order to translate DNA
(RNA) you must first crack the
genetic “code”!
The genetic code is a triplet code in which a group of
three bases (codon) of a
DNA molecule code for a
particular amino acid.
Reading the Genetic Code:
Note that the code is sometimes
redundant, but never ambiguous.
It is also (nearly) universal, allowing for DNA from one species to function
in another!
Arabidopsis thaliana C24 wild type (left) and transformed (GFP; right)
Tobacco plant expressing a firefly gene (luciferase)
Herman, at right, makes the human milk protein, lactoferrin, which is an antibacterial protein
that can be used to treat immunosuppressed patients and could be incorporated into infant
formula.
From From mRNA to mRNA to ProteinProtein
Translation: From mRNA to Protein
mRNA is translated by an interpreter, transfer
RNA (tRNA).
tRNA transfers the correct amino acid from
the cytoplasm to a ribosome.
Translation: From mRNA to Protein
The ribosome adds amino acids to the growing end of a
polypeptide chain.
Understanding Understanding Transcription and Transcription and Translation Allows Translation Allows You to Predict the You to Predict the
Effect of Effect of Mutations!Mutations!