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Transcript of GENE
GENEEXPRESSION
Spark Starter
• Where does the mRNA travel to after it is synthesized in the nucleus?
• What molecule does the mRNA bind to at this site?
Today’s Task..
• Review Transcription • Translation• mRNA provides the code for Amino acids• Amino Acids are the building blocks of proteins
Video…
Transcription Recap…
1. RNA polymerase unwinds DNA
2. RNA polymerase adds RNA nucleotides
(A ↔ U, G ↔ C)
3. mRNA is formed! DNA reforms a double helix
Transcription recap…
• RNA polymerase makes mRNA using DNA sequence
• mRNA leaves the nucleus for the cytoplasm
TranslationTRANSLATION: process of “decoding” a strand of mRNA to create proteins
To Accomplish this the cell uses 2 special molecules: the Ribosome (rRNA) and the tRNA
RibosometRNA
Translation
• Ribosomes translate mRNA into an amino acid sequence
• Amino acids form proteins
To a ribosome!
Let’s Break It Down!
Translation—process of “decoding” a strand of mRNA to create proteins
Step 1: Reading the Codon
Step 2: Matching the Codon with the anticodon
Step 3: Elongation
Step 1: Reading the Codon
Codons = 3 nucleotides in a row
2nd Ribosome reads the codon on mRNA
A C G
anticodon
amino acid
1st mRNA binds to the Ribosome
Step 1: Reading the Codon
Codons = 3 nucleotides in a row
Box the Codon on your paper…
AUGACGGAGCUUCGGAGCUAGGAUUAC
CACAUGGAGGAUUACCUGCUAGCUAGU
ACGGGCUGCAUGAGCUUCGGGAGCUUC
Let’s Break It Down!
Translation—process of “decoding” a strand of mRNA to create proteins
Step 1: Reading the Codon
Step 2: Matching the Codon with the anticodon
Step 3: Elongation
The Anticodon is found on the tRNA (Transfer RNA)
Anticodon = 3 nucleotides on one end of a tRNA
Anticodons base pair with complementary bases on mRNA
anticodon
amino acid
A C G
Step 2: Matching the codon w/t the anticodon
Ribosome reads the codon and matches it with its complementary 3 base sequence called the Anticodon
anticodon
amino acid
A C G
Step 2: Matching the codon w/t the anticodon
Transfer RNA (tRNA)
Carries a unique amino acid that corresponds with its Anticodon
Each tRNA with a different anticodon will carry a different amino acids
Anticodon = 3 nucleotides on one end of a tRNA
Create the Anticodon to the following codon
AUGACGGAGCUUCGGAGCUAGGAUUAC
CACAUGGAGGAUUACCUGCUAGCUAGU
ACGGGCUGCAUGAGCUUCGGGAGCUUC
Step 2: Matching the codon w/t the anticodon
Anticodon = 3 nucleotides on one end of a tRNA
Create the Anticodon to the following codon
Step 2: Matching the codon w/t the anticodon
AUGACGGAGCUUCGGAGCUAGGAUUACUACUGCCUCGAAGCCUCGAUCCUAAUG
CACAUGGAGGAUUACCUGCUAGCUAGUGUGUACCUCCUAAUGGACGAUCGAUCA
ACGGGCUGCAUGAGCUUCGGGAGCUUCUGCCCGACGUACUCGAAGCCCUCGAAG
Let’s Break It Down!
Translation—process of “decoding” a strand of mRNA to create proteins
Step 1: Reading the Codon
Step 2: Matching the Codon with the anticodon
Step 3: Elongation
anticodon
amino acid
A C G
Step 3: Elongation
Transfer RNA (tRNA)
The tRNA with its amino acid binds to the ribosome
The ribosome then starts connecting amino acids together to form a protein
Codon triplets code for 1 of 20 amino acids
Step 3: Elongation
Genetics Code Chart
Anticodon = 3 nucleotides on one end of a tRNA
Step 3: Elongation
AUGACGGAGCUUCGGAGCUAGGAUUAC
CACAUGGAGGAUUACCUGCUAGCUAGU
ACGGGCUGCAUGAGCUUCGGGAGCUUC
Match the Codon with its corresponding amino acid using the Genetics Code chart
1 “start” codon 3 “stop” codonsCodons
Steps of Translation
1. mRNA attaches to ribosome
mRNA
Steps of Translation
2. tRNAs add amino acids based on how anticodons match to mRNA
mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
mRNA
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
2. tRNAs add amino acids based on how anticodons match to mRNA
Steps of Translation
3. Protein is released from ribosomes!
Protein chain
Stop codon
Steps of Translation
Protein chain
3. Protein is released from ribosomes!
Summary
DNA
RNA
PROTEIN
(Transcription)
(Translation)
Practice1.DNA sequence: AAC TGA CTG ATT GCA TGC• What is the complementary DNA sequence?• What is the complementary RNA sequence?
2.DNA sequence: TAG CAT TGG GCA TCA CGA• What is the complementary DNA sequence?• What is the complementary RNA sequence?
TTG ACT GAC TAA CGT ACG
UUG ACU GAC UAA CGU ACG
ATC GTA ACC CGT AGT GCT
AUC GUA ACC CGU AGU GCU
Determine the amino acids for this strand of mRNA:AUG GCA AGU UCU UGA
Practice
Met – Ala – Ser – Ser – STOP
Determine the amino acids for this strand of mRNA:UGU AGA GAU CUC UAA
Practice
Cys – Arg – Asp – Leu – STOP