Transcript PowerPoint Presentation - Ch. 10 Molecular Biology of the Gene

Ch. 10 Molecular Biology
of the Gene
10.6 – 10.8
The flow of genetic information
from DNA to RNA to Protein
The 2 steps for protein synthesis
• Follow the Flow of
Instructions:
DNA in the nucleus
Transcription to
RNA leaves the nucleus
Translation to
Protein synthesis in the
cytoplasm
• Transcription is:
• The transfer of
genetic information
from DNA into an
RNA molecule
• Translation is:
• The transformation of
the information in the
RNA into a protein.
• 1799 in Rosetta,
Egypt, the Rosetta
Stone was found,
deciphering Egyptian
hieroglyphics to
Egyptian script to
Greek.
• How is this like our
study of genetics?
• DNA transcribed to
RNA translated to a
polypeptide.
SO, how does this occur?
• Transcription and
translation are linguistic
terms, so…..
• nucleic acids (DNA and
RNA) and polypeptides
(chain of amino acids
linked by peptide bond)
Have their own language!
What is their language?
• A, T, G, C in DNA and A, U, G,
C in RNA
• One gene can contain
hundreds or thousands of
nucleotides, and
one molecule of DNA
may contain thousands of
gene.
• Nucleotide bases on the
RNA are complementary
to those on the DNA
strand. How?
• DNA was a template.
• What is the strand in
the middle?
• RNA
• Is this transcription or
translation?
• Transcription
• The purple
polypeptide chain is
the result of
translation. How?
• The language of the
sequence of
nucleotides in RNA
(Codons) dictate the
sequence of amino
acids of the
polypeptide.
• Triplets of bases are the
“smallest” words that
specify amino acids.
They’re called…
• Codons
• 3 base codons in DNA
are transcribed into
complementary RNA
codon, then translated
into amino acids that form
a polypeptide chain.
• Codons such as AUG
not only signal start of
a chain but, code an
amino acid.
• Do all have double
duty?
• UAG, UGA, UAA do
not code an amino
acid, but they do
signal stop.
• There are 4 bases
and 3 nucleotides per
codon, so
• Calculate the total
number of codons.
• 64 or 43
• Compare this to the
total number of amino
acids
• 20