Protein Synthesis. Codes! DNA contains codes –Codons 3 nucleotide bases = amino acid –Sequence...
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Transcript of Protein Synthesis. Codes! DNA contains codes –Codons 3 nucleotide bases = amino acid –Sequence...
Protein Synthesis
Codes!
• DNA contains codes– Codons
• 3 nucleotide bases = amino acid
– Sequence of amino acids = proteins
– DNA copied = mRNA (messenger RNA)
Transcription and Translation
• Transcription– Creation/synthesis of mRNA from a DNA
template strand
• Translation– Ribosomes make proteins using the mRNA
strand made by transcription
Transcription
• One strand of DNA is copied
• Creates mRNA– mRNA travels OUT of the nucleus to the
cytoplasm (where the ribosomes are)
mRNA
• Ribonucleic Acid
• Structurally similar to DNA– U instead of T– Single-stranded
• Used to create proteins
• AUGACGGUU
Vocab
• Codon– Basic unit of the genetic code– Sequence of 3 adjacent neucleotides in DNA
or mRNA
• Amino Acid– RNA codon
Translation3 Main Steps
1. Initiation
2. Elongation
3. Termination
Translation StepsInitiation
1. Ribosomes attach to an mRNA strand
Translation StepsElongation
2. Translation begins at the AUG codon
AUG means GO!
tRNA Molecules
tRNA
– Recognize both specific mRNA codons and the amino acids that match those codons
– Contains an “anti-codon” which attracts specific amino acids
• Similar to the complimentary base pairing rule
Translation StepsElongation
3. Transfer RNA (tRNA) molecules carry anti-codons
These anti-codons find complimentary codons and attach them to the ribosome and mRNA
Translation StepsElongation
4. The ribosome travels down the mRNA and reads the codons
Translation StepsElongation
5. The ribosome pauses at each codon and waits for the tRNA to bring the correct amino acid
6. Each amino acid is bound together by a Peptide Bond!
Translation StepsTermination
7. The process continues until the ribosome reaches a stop codon
Translation StepsTermination
8. Everything breaks apart!
Final peptide bonds are created, the ribosome breaks apart, and the polypeptide (protein) is released
Translation StepsTermination
9. The Protein (polypeptide) folds into its specific shape.
Shape determines function!
10.The Protein is ready tobe used by the body!
64 codons code for 20 different amino acids