Question of the Day
Question: Give the RNA sequence made from the
DNA sequence ATGCTAGCT.
UACGAUCGA
Nucleus
RNA
DNA
Central Dogma of Molecular Biology:
DNA
 RNA
 Protein
Part 1: Transcription
• Transcription- making RNA from DNA code in nucleus
• Transcription- creation of RNA using DNA
Nucleus
RNA
RNA
polymerase
DNA
Part 1: Transcription
Discuss With Your Partner:
1. Where does transcription take place? nucleus
2. What enzyme is responsible for carrying out
transcription? RNA polymerase
3. What does transcription produce? RNA
Discuss with Your Partner:
• What does “translation” mean to you?
• What are some ways that we could we
“translate” the following sentence:
When school is over, I am going to
hang out with my friends.
Part 2: Translation
• Translation- using RNA instructions to build a protein
Part 2: Translation
• Translation- using RNA instructions to build a protein
1. mRNA (messenger) carries code to cytoplasm
2. mRNA is read 3 nucleotides at a time (1 codon)
Ex: AUG
Codon = 3
nucleotides
Part 2: Translation
3. 1 codon codes for 1 amino acid, which is transferred by tRNA
4. Anticodon part of tRNA must complement mRNA codon
Ex: AUG codon (mRNA) & UAC anticodon (tRNA)
amino acid
amino acid
amino acid
anticodon
Part 2: Translation
5. Amino acids linked
together by a ribosome to
make a polypeptide
Part 2: Translation
6. Polypeptide is folded into a protein
Polypeptide
Protein
Part 2: Translation
Part 2: Translation
• Using codon wheel:
– For decoding RNA
– Work inside to
outside
What amino acid
does the codon
AUG code for?
Methionine
(start)
What amino acid
does the codon
GGG code for?
Glycine
What amino acid
does the codon
CAC code for?
Histidine
What amino acid
does the codon
UAG code for?
Stop
(no amino acid)
Part 2: Translation
• Using codon wheel:
– For decoding RNA
– Work inside to
outside
– AUG = start codon
– UAG, UAA, UGA =
stop codons
Protein Synthesis Review:
DNA:
TACCCCGTGATC
mRNA: AUG-GGG-CGA-UAG
Protein: Met-Gly-Arg
1. What codons…
a. are in the RNA sequence AUGCCGUUUGGAUAG?
b. What amino acids do they code for?
2. What codons…
a. are in the RNA sequence AUGAAUGUUUGG?
b. What amino acids do they code for?
3. What amino acids will the DNA sequence
TATGCTAGACTG eventually code for?
Put ‘Em In Order!
3.
5.
2.
4.
1.
a) tRNA molecules carrying amino acids and begin to match up
with codons on the mRNA sequence according to the
anticodons on the tRNA molecules
b) The polypeptide chain is finished and will later be folded into
a complete protein
c) The mRNA leaves the nucleus and travels to the cytoplasm
through pores in the nucleus
d) The amino acids are linked (bonded) together by a ribosome,
a protein-building organelle
e) DNA is unwound by RNA polymerase and mRNA is created
from the DNA sequence according to the base pairing rules