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!