Lab Make-Ups
If you missed the strawberry lab or the candy
dye lab you need to Borden ASAP to sign-up.
The Candy dye lab kit will be returning to Fred
Hutch Thurs., March 1 and will not be
available after that.
Warm-up
DNA Review 2/22/07
Write the DNA strand and complimentary base
pairs that match:
#1 AGC AGG CTT AGT ACT CGA
#2 GCT AGT ACC CAT CTG GAT
AGENDA
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Warm-up
Stamp Obj. 12.3
Go over dye lab results
Notes: Transcription/Translation
In class activity transcription/translation
Discuss lab on for Monday
No homework
Transcription and
Translation: Protein
synthesis
What we already know…
 DNA
encodes the information to
make proteins
 DNA cannot leave the nucleus
 Protein synthesis occurs outside
of the nucleus, on a ribosome
How does it happen?
DNA encodes the information to make
RNA.........and RNA molecules
function together to make protein
Structure of RNA
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Single stranded
Built of nucleotide
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5-Carbon Sugar =
ribose sugar
Phosphate Group
Nitrogenous base:
 Adenine, Uracil,
Guanine, and
Cytosine
NO THYMINE IN RNA
3 Types of RNA
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Messenger RNA (mRNA)
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Transfer RNA (tRNA)
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carries information to ribosomes for protein
production
brings specified amino acids from the cytoplasm
to the ribosomes where the protein chain is made
Ribosomal RNA (rRNA)
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the ribosome and protein
3 Types of RNA
Transcription
DNA  mRNA
Transcription
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molecule of DNA is copied into a
complementary strand of mRNA
Occurs in the nucleus
How does it happen?
DNA unzips and exposes one gene as a
template
A complementary strand of RNA is formed
1.
2.
o
o
3.
4.
A–U
G–C
mRNA strand exits nucleus & moves into
cytoplasm
The two strands of DNA re-attach and recoil
Try it yourself …
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Transcribe Strand 1 of the DNA molecules
below
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1- T T A G G A CT G C A A T T G
2-A A T C C T G A C G T T A A C
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1- C A G T C C G A A C G T T T A
2- G T C A G G C T T G C A A A T
Answers
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A A U C C U G A C G U U A A C
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G U C A G G C U U G C A A A U
Translation
mRNA  protein
Translation
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mRNA is “read” & a protein is created from
amino acids
Occurs at ribosome
Steps of Translation
1. mRNA moves to ribosomes
2. rRNA on the ribosome binds to the mRNA
and starts “reading” codons.
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Codons – 3 letter code that specifies a particular
amino acid.
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start codon = AUG
stop codon = UAA, UAG, or UGA
3. AUG binds to the first anticodon of tRNA
4. tRNA transfer amino acids until the rRNA
reaches a stop codon on the mRNA
5. ribosome releases protein and mRNA
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protein to be used by the cell
mRNA to synthesize more protein molecules
mRNA-amino acid chart
Try it yourself!
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DNA template strand
DNA: TACGATCGAACGTAT
mRNA codon:
tRNA anticodon:
Amino Acids :
Transcription/Translation video
http://www.youtube.com/watch?v=1GWI7qcQW
bA
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Transcription/Translation Activity
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Tape your work into lab notebook, do not take
home the main worksheet
mRNA Activity
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Here is a strand of mRNA. Arrange your tRNA
molecules to determine the sequence of Amino Acids
that this mRNA codes for.
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AUG CUA UCA UCA UAU GGA GUA ACU 
AGU UUU CGC AUU CCG CAU ACA CGG GUU 
CUC CCU CAC AGG UGG GGG UGU CUA ACC 
UUA CCC GCA UCG UAA
Mutations
Mutations lead to mistakes in the proteins
being made.
 Mutations can happen during DNA replication
and change the “blueprint of the cell”
Or
During transcription or translation so a wrong
protein or no protein is made
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Types of mutation
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Point mutation- one nucleotide changes
Frameshift mutation- an insertion or deletion
of a nucleotide that changes all codons after
that point
Chromosomal mutation- all of the genes on a
certain chromosome can be affected. Or
change the location of genes on the
chromosome.
Transcription
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The information in the DNA not only contains
amino acid (aa) sequences, it also has “junk”
DNA.
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Exon: RNA that codes for a.a.
Intron: junk RNA/DNA
Enzymes in the nucleus snip out the exon
and the RNA molecule is protected and sent
outside of the cell.
mRNA splicing