amoeba sisters: why is rna just as cool as dna?
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Amoeba Sisters: Why is RNA just as Cool as DNA?. http:// www.youtube.com/watch?v=0Elo-zX1k8M. Protein Synthesis. Transcription and Translation. CENTRAL DOGMA OF BIOLOGY How is information passed? _____ → ______ → ________. DNA. RNA. PROTEIN. - PowerPoint PPT PresentationTRANSCRIPT
Amoeba Sisters: Why is RNA just as Cool as DNA?
• http://www.youtube.com/watch?v=0Elo-zX1k8M
Protein Synthesis
Transcription and Translation
CENTRAL DOGMA OF BIOLOGY How is information passed?_____ → ______ → ________DNA RNA PROTEIN
Then the protein “DOES SOMETHING”that shows up as a ________trait
The Genetic Code• The sequence of nitrogen
bases along a DNA strand that code for the synthesis of proteins.
• There are 20 different amino acids ( the building blocks of proteins.)
WHAT AREGENETIC TRAITS ?
The same 20 amino acids make up all proteins.
THE 20 AMINO ACIDS: A TYPICAL PROTEIN:
HOW CAN JUST 4 BASES GIVE DIRECTIONS TO MAKE 20 AMINO ACIDS?
Message is read in groups of 3 = _________
UCGCACGGU UCG-CAC-GGU
CODON
Codons represent different amino acids
Serine- Histidine- Glycine
ATG
GCA
DNA mRNAUAC
CGU
triplet codontriplet = 3 nucleotides on a DNA molecule
codon = 3 nucleotides on an mRNA molecule
DNA (triplets)mRNA (codons)
ATT CCT GAG TTCUAA GGA CUC AAG
Each codon codes for a specific amino acid. The sequence ofamino acids determines the type of protein to be made. Remember that amino acids are the monomers of proteins.
All organisms use the same genetic code for amino acids andassembling proteins. That is why the genetic code is said tobe universal.
REMEMBER DNA to RNA A=U !! There is NO THYMINE
Some rules of reading genetic code
The m-RNA CodeSection 12-3
64 possible codons
Some amino acidshave more than onecodon.
START= _______
3 codons for _____
AUG
STOP
Part I: Transcription
• occurs in the nucleustranscription = process where DNA is copied into mRNA
DNA cannot leave the nucleus but the message of DNA needsto get out of the nucleus
mRNA can take message of DNA out of the nucleus
What is the message of DNA?? the order of nucleotides that determine a specific protein
Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only
Steps of Transcription1. Helicase unzips DNA helix2. RNA polymerase assembles mRNA
nucleotides but base pairing rules changes slightlya. Thymine in DNA pairs with Adenineb. Adenine in DNA pairs with Uracilc. Cytosine still pairs with Guanine
T - -A - -C - -A - -A - -A - -C - -T - -T - - T - -G - - A - -
DNA
U A C A A A C U U U G A
mRNA
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- - A- - T- - G- - T- - T- - T- - G- - A- - A- - A- - C- - TW
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Step 1: Helicase enzyme “unzips”
double helix by weakening
H-bonds
Step 2: RNA polymerase
enzyme forms complementary mRNA strand
• Transcription is complete when the mRNA leaves the Nucleus and enters the Cytoplasm.
• The CODONS will then be translated at the ribosome.
The Genetic Code: CODONS code for amino acids
1. UUC
2. CCCProline
Phenylalanine
3. AGCSerine
4. UGAStop
Part II: Translation
• occurs in the ribosomes of the cytoplasm
translation = process where the cell uses information from mRNA to produce proteins
The language of DNA is translated into the language of amino acids
1. The mRNA strand attaches to a ribosome in the cytoplasm2. tRNAs carry specific amino acids to the ribosome3. The tRNA anticodon pairs with the correct mRNA codon4. The ribosome slides along the mRNA to the next codon
while the tRNAs bring more amino acids5. The amino acids are joined together by peptide bonds6. Continues until a STOP codon is reached
Steps of Translation:
Some rules of reading genetic code
mRNAAUG
CGU
codonU
AC
tRNA
Startcodon = 3 nucleotides on an mRNA molecule
anticodon = 3 nucleotides on a tRNA molecule
anticodon
tRNA is responsible for bringing amino acids to theribosome. tRNA has an anticodon, which is the opposite ofthe mRNA codon.It is important to remember that the mRNA codon determines the amino acid, NOT the tRNA anticodon.
mRNA:tRNA:aminoacid:
U U A C G A A G C U C GA A U G C U U C G A G C
Leucine - Arginine - Serine - Serine
Transcription vs. Translation Review
Transcription• Process by which genetic
information encoded in DNA is copied onto messenger RNA
• Occurs in the nucleus• DNA mRNA
Translation• Process by which
information encoded in mRNA is used to assemble a protein at a ribosome
• Occurs on a Ribosome• mRNA protein
DNA:
mRNA:
tRNA:
amino acids:
TAC AAG CTT GGG ATA CGC TAA ATT
UUC GAA CCC UAU GCG AUU UAA
AAG CUU GGG AUA CGC UAA AUU
Phenylalanine - Glutamic Acid - Proline - Tyrosine - Alanine - Isoleucine - Stop
**Remember – use the mRNA codons to determine the amino acids!! NOT the Anti codons
Complete the Following Chart:
AUG
UAC
Start -