Transcript DNA YOUTUBE CLIPS

April 12, 2010
1. Tell me about your spring break! (a
GOOD paragraph, 4-5 sentences!)
2. Write down at least 3 things you know
about DNA
3. Write down at least 2 things you know
about RNA.
DNA Structure
Make observations of DNA pictures.
Write down AT LEAST 3 things you
notice about the structure of DNA
DNA vs. RNA
Similarities
• Nucleotides as building blocks
• Sugar-Phosphate backbone
• Nitrogen bases (A, C, G, and other)
DNA vs. RNA
Differences
# strands
Type of Sugar
DNA
2
deoxyribose
RNA
1
ribose
Bases
A-T
C-G
A-U
C-G
*There is no T
in RNA
DNA YOUTUBE CLIPS
1.
2.
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4.
The Secret of Life - Discovery of DNA Structure
The Secret of Life 2
Watson and Crick
DNA Extraction
Central Dogma of Biology
• BIG IDEA
– DNA  RNA  Protein
Protein Synthesis Part 1:
Transcription
• Overall: DNA is changed into mRNA
– (messenger RNA)
• Occurs in the nucleus
– Remember: DNA cannot leave nucleus b/c it’s too
big!
Protein Synthesis Part 1:
Transcription
• Steps
1.Enzymes unwind and unzip DNA
– Must be able to access the nitrogen bases
– The order of nitrogen bases determines
characteristics of organisms; this is where the
genetic info is held!
Protein Synthesis Part 1:
Transcription
2. mRNA “reads” DNA (enzyme helps bring
in nucleotides and bond them together)
– Follows base pairing rules:
– EX
DNA
RNA
C
G
G
C
T
A
A
U
***There are no T bases in
RNA, use Uracil (U) instead
DNA
TAC
AAC
TTG
GCG
TAT
TAA
CGT
mRNA
AUG
UUG
AAC
CGC
AUA
AUU
GCA
Protein Synthesis Part 1:
Transcription
3. SINGLE STRAND mRNA exits nucleus
with code; DNA zips and winds back to
normal
Transcription = making RNA
TRY ONE!
Given DNA CODE
ATG, CCG, TAC, AGA, GTC, TTC
Make a complimentary mRNA Strand.
UAC, GGC, AUG, UCU, CAG, AAG
Protein Synthesis Part 2:
Translation
• Overall: mRNA is changed into protein
• Occurs in the cytoplasm
Protein Synthesis Part 2:
Translation
• Steps
1. mRNA code is “read”
– every three bases represents a codon or a triplet
– each codon = 1 amino acid
– start codon is AUG; anything before the AUG
sequence is junk.
• EXAMPLE
– mRNA: AACUAUGCAAUUAGCAU
Protein Synthesis Part 2:
Translation
2. tRNA brings in appropriate
amino acid (transfer RNA)
– has an anticodon that follows
the base pairing rules to match
mRNA strand
– Ex. mRNA codon of AUG has a
tRNA anticodon of UAC
Protein Synthesis Part 2:
Translation
3.translation will stop when it reaches a STOP
codon (according to chart)
• Without transcription or translation, our genetic
information would be useless -- a recipe on a
page with no way to bake the cake.
Protein Synthesis
Transcription and Translation
From RNA to Protein Synthesis
Protein Synthesis
Language of Genetics
Words in DNA/RNA are made up of 3 letters
– Ex) AUG, TUC, CCC, GGG, ATG
• DNA: A word is called a “code”
• mRNA: A word is called a “codon”
• tRNA: A word is called an “anti-codon”
– Opposite of codon
Examples
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DNA Code – TAC
mRNA Codon – AUG
tRNA Anti-Codon – UAC
Amino Acid - Methionine
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•
DNA Code – GAC
mRNA Codon – CUG
tRNA Anti-Codon – GAC
AA – Leucine
Complete the Process
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DNA
CTTACGGGTTACGCATT
mRNA – Break it down to 3’s
(GA)AUG, CCC, AAU, GCG, UAA
tRNA –
(CU)UAC, GGG, UUA, CGC, AUU
AA Chain – Use mRNA and code wheel!
Methionine, Proline, Asparagine, Alanine, Stop
Summary
• DNA code is Transcribed to mRNA codon
• mRNA “start” codon (AUG) is Translated
and tRNA anticodon attaches
• Amino Acids are strung together at
Ribosome until “stop” codon is reached
• AA strings are Proteins